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Mini Torii SE Amplifier (Read 34564 times)
Fireblade
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Re: Mini Torii SE Amplifier
Reply #150 - 04/07/12 at 21:42:10
 
I've been assuming all along that the volume sensitivity grows linearly with the analog input signal voltage (other things being equal), but it may well be an exponential function.  Meaning, anything beyond 2.0 V may increase loudness at ever increasing rates.  

If the original design is optimized for the [sub 1 V to 2 V max] target, we may be at  the steepest stage of that function after the 2 V threshold.  This may explain the inordinate sensitivity with sources even moderately higher than the 2 V mark.  If so, Radushka is in a greater predicament than I, just because of that 0.25 V difference.

This may also explain the apparent indifference of using driver tubes with different gains, so long as that source output does not go beyond the 2.0 V max.

If this reasoning is correct, I would expect those using 12aT7 and highly sensitive speakers and not experiencing such loudness sensitivity (an apparent paradox), most probably have sources strictly under, or at, the 2.0 V mark.

Anybody cares to comment?
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #151 - 04/07/12 at 21:47:57
 
wouldn't that be a function of the pot design too? Or predominantly? I emailed 'alpha inc.' a hi res photo of the pots and am waiting for them to send me a spec list.
We didn't go eat sushi after all, I am home obsessing about Dale Vishey 1% resistors and Goldpoint atts that will solve all my problems. ALL my problems Smiley
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Fireblade
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Re: Mini Torii SE Amplifier
Reply #152 - 04/07/12 at 21:51:56
 
Not if that same pot design is replicated in most M-T's around.  The paradox would not occur and everybody (not only the ones with highish DAC output voltage) would have experienced the same ultra sensitivity issues.

Don't get obsessed, just enjoy the challenge  ;)
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erik2a3
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Re: Mini Torii SE Amplifier
Reply #153 - 04/07/12 at 21:53:55
 
Sushi with girl friend is better thsn sny sttnuator you'll ever find.  I just tried an experiment: digital output from CDP into Lexicon DSP, and Lexicon into mini torii.  Mini torii volume control up about 3/4 way.  Using the Lexicon this way, which has it's own volume control in the preamp, works quite wondefully well.  Rmember, that if the MT were a power amp, it would used a fixed, 100k ohm resistor on the grid of the first half of the input stage to ground.  This equates to the volume controls being turned all the way up, which provides the greatest resistance relative to ground.

So, even if your source had a 5 volt output, if you have a transparent linestage, which the Lexicon very much is, ypu can adjust the gain between the volume control of the preamp and dual pots of the Mini Torii -- if you don't mind the extra electronics between the two.  I don't, it works extremely well.
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erik
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #154 - 04/07/12 at 21:58:12
 
that would mean that I replace the pots with high quality 100k resitors and use the mini t as a power amp? WHile adjusting the volume from the output of the DAC?

DO you think I could solve the issue by building my custom atts?
I am a little hypoglycemic, that is why my brain is a little slow on this issue.  I'll be in the kitchen helping my gf cook.
'helping'
hah
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #155 - 04/07/12 at 22:03:43
 
you may have noticed I am hell-bent on replacing the stock pots.
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erik2a3
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Re: Mini Torii SE Amplifier
Reply #156 - 04/07/12 at 22:04:52
 
My brain is a little slow, period!  I had sushi for lunch today -- I love it!!

Sure, I actully toyed with the idea of using it as a straight ahead power amp.  You take out the volume controls and replace them with a fixed resistor.  This may or may not solve the problem, though....

With a preamp in the mix (I know you don't like the idea), you can sort pf balance things out between both components.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #157 - 04/07/12 at 22:15:16
 
I like the idea, but I think good volume pots will work wonders in term of sound quality and I don't have any more money to invest in expensive parts (after I buy the atts and their resistors that is:-)) .
I still do not understand what determines an att's nominal resistance.  Erik said a ratio of 1 to 10 btw output Z and pot resistance was optimal. The dac's output z being 1.3, my att should be 20k let us say (13k sounds odd). How do I achieve that on a custom att??? I will look it up on the Goldpoint site, they have lists about just that.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #158 - 04/07/12 at 22:20:31
 
http://www.flickr.com/photos/71648043@N02/6908641606/

there is a 'resistor designator' bottom left, going to gnd, I suppose that one determines the resistance of the att when it is wide open? (maximum volume I presume)
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Fireblade
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Re: Mini Torii SE Amplifier
Reply #159 - 04/07/12 at 22:27:20
 
As I mentioned yesterday, a definite solution is to 'ride the gain' through the use of a second component, be it a preamp, a ZStage or an output controllable DAC.  Yet, it should not be the case, as the M-T design is supposed to be robust enough to handle the popular range of market sources' (CD players, DACs) output specs.  Besides, this would be against the 'purist' approach!

Although I've been contemplating the addition of a ZStage to the M-T myself, just to be able to get the benefits or 'riding the gain' (better dynamics, for example), I had planned to wait until the gear is broken-in before making any additions or adjustments.

The other straightforward solution is to replace our DACs with something under the 2.0 V mark output.  But I would hate to do that just now.  I think I'll wait for my Mini Torii and DM945's to arrive and we'll see.  

In the case of Radushka, a fine, highly-stepped attenuator design may be just the ticket (i.e., an attenuator with double the number of ticks per arc-sweep).  Sonic degradation is the only possible risk here (not because of the concept, but in terms of design and build quality).  

Just my thoughts.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #160 - 04/07/12 at 22:32:00
 
the atts I am looking at are the series, not the ladder type, but they have a very good reputation, especially when paired with non-noisy resistors. I could make a non linear att, with the most used volume levels right after the zero position, so I can dial in directly :
1st click: day level volume,
2nd click : evening
3rd click: late night
linear from 4th click on
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erik2a3
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Re: Mini Torii SE Amplifier
Reply #161 - 04/07/12 at 22:33:19
 
I guess I think this isn't an attenuator issue.  I have used very expensive stepped attenuators years ago, and found the only real improvement had to do with the better channel to channel tracking in the stereo voume control.  Sound-wise it was perhaps marginally better than the cheap carbon comp control.  I've been using Alps blue volume controls almost exclusively, which are a good balance in terms of cost and performance.

I could be completely wrong.  Maybe a nice Goldpoint, which I think are very but also very expensive controls would make all thendifference in the world.....my gut feeling is that it won't change the sensitivity problem appreciably.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #162 - 04/07/12 at 22:33:53
 
Fireblade, do you think an att would degrade the sound more than a preamp? A preamp has its own volume pot. I am worried now, what do you mean by sonic degradation?
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #163 - 04/07/12 at 22:35:34
 
so Erik, from your experience you think a 200$ att will not bring about a marked improvement over the stock volume pots?
regardless of the input sensitivity issue. Just sound wise
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Fireblade
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Re: Mini Torii SE Amplifier
Reply #164 - 04/07/12 at 22:48:21
 
Not at all.  In both cases it's going to depend on the quality of their design, materials, build, etc.  Although, what Erik is pointing out may suggest the attenuator won't really solve the sensitivity issue.  

I'm not qualified to suggest anything other than trying the attenuator should at least allow you that in-between volume target you're missing now.  Assuming there's no sonic degradation and the cost is less than an additional component, you'll be better off in purists terms and presumably able to dial-in the optimum volume level.

If, on the other hand, you want to take advantage of the situation and tap the benefits of riding the gain, there's always the second-component alternative, if you care to invest in it.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #165 - 04/07/12 at 22:56:33
 
GOLDPOINT MONAURAL MINI-V STEPPED ATTENUATOR (2) 10K, 20K, 25K, 50K or 100K

I still do not understand which resistnce value works best in my set up. The dac puts out 2.5v, and output Z is 1.3K. How do I match up the dac with the mini t here? 20k to replace the stock 100k??
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erik2a3
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Re: Mini Torii SE Amplifier
Reply #166 - 04/07/12 at 23:04:54
 
Radu: I'm not really saying it wouldn't be worth it.  Like caps and other passive parts, the end result is probably kind of subjective.  Fireblade stated this as I also see it -- that the type of attenuator may not be the main culprit.  With two basic types of controls, those being log taper and linear, the really nice attenuators approximate the log or audio taper with values of resistance that match the way we perceive incremental changes in volume, which is how the cheap pots in the torii, mini, also do.  Fwiw: I am honestly not in the least inclined to change them.  But this just me, only becausenI have learned after truly ridiculous amounts of comparing caps, resistors, transformers, volume controls, etc., thatmthe best one in a particular circuit is quite truly not necessarily the most expensive one.  I have had $60 capacitor in one hand, and a $0.25 one in the other, and after comparing both both decided to use the cheaper. But the opposite has also been the case.  My point is that despite the lower costnof some of the parts on this amp, they work very well, and for that I am happy!  I think a really good sounding preamp is what would do the trick in your case...but I might be completely off base.  I say this because I just tried it and it can work as well or better than not having one in the signal chain.
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Fireblade
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Re: Mini Torii SE Amplifier
Reply #167 - 04/07/12 at 23:10:10
 
I would encourage you to ask Steve this question, directly.  That phone call is worth it, given all the uncertainties involved, and may shed some light on this issue, once and for all.  Sometimes, defining the right question is tantamount to solving the problem optimally, especially if you can talk to The Man.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #168 - 04/07/12 at 23:12:10
 
I am listening carefully Erik! I am still afraid that the Vcaps might have made it sound too forward compared to the original caps, so I can see in practice how expensive parts do not automatically improve things. At this point, even though a preamp might be the best solution, I don't want (can't rather, who doesn't want? Smiley)
to invest in a more than decent preamp. That is why I am focusing on the volume pots, not as much to solve the gain issue as to make sure such an important part as the volume pot gets a fair treatment.
Yeah, I should call Steve. I am just a bit intimidated...Plus I installed Vcaps in the man's amp. I am ashamed Smiley
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #169 - 04/07/12 at 23:20:35
 
I wrote to Steve. He usually answers. Otherwise I will call. I would still like to know what attenuator value I should be looking at.
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Fireblade
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Re: Mini Torii SE Amplifier
Reply #170 - 04/07/12 at 23:43:29
 
I wasn't aware you had VCaps (Teflon or Copper-Teflon?).  This may be the 'X' variable that may explain the odd behavior and the apparent paradox.  Which means the M-T design is robust, after all, in handling moderate deviations in DAC output voltages beyond the 2.0 V mark (with the original Caps in place).  So, Erik was right in discarding a possible volume pot issue.

You may still need that stepped attenuator now to compensate for the added VCap effect, and only Steve may give you the specs for it.  It's odd, but I thought Steve mentioned once that VCaps would not fit in the Mini-Torii (there are 4 Caps total), given their size.  He stated VCaps were not an option for the Mini Torii.

Anyway, good luck!
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #171 - 04/08/12 at 00:16:11
 
Fireblade,

the Vcaps did not add anything to the gain issue. Rivieraranch had warned me that they would add even more gain, however I haven't noticed an iota of difference. I had this issue even with my 2V cd player, with the stock volume pots of course.
I had read Steve's recent (feb 2012) post about Vcaps not fitting inside the MT. In light of my successfully installing 0.22 Vcaps in there, I do not fully understand. He also mentioned there are 4 caps to be replaced, which would make it expensive. That I can see immediately Smiley I do not know how big the 0.1 Vcaps are, maybe those would not fit indeed. Although where there's a will, there's a ... drill.  I still need to listen before I decide it was a good idea to replace the stock caps. I recently replaced a bad resistor and I believe it screwed up my soundstage focus. So far the Vcaps have brought about a vast change in musicality and detail (the kind of detail you would crave). Change is an euphemism, I dare not say improvement. For me and my ears. If anything though, the presentation may have become more forward, which I dislike. But like I said, it may be due to a few odd resistors I put in there, we'll see.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #172 - 04/08/12 at 00:22:42
 
Here is a schematic of how to add a resistor in series with the signal input before the att, which is what Erik suggested in the first place and which I now have come to consider the easiest way out, in case I still have issues with it after I install the att.



add usable steps to attenuator par raduschkamuschka, sur Flickr


resistor values par raduschkamuschka, sur Flickr
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Fireblade
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Re: Mini Torii SE Amplifier
Reply #173 - 04/08/12 at 01:52:28
 
Having a more 'in your face' or forward sound with the VCaps may contribute to the perception of inordinate loudness also.  

It's interesting from the schematics you upploaded to see how my earlier argument for a highly stepped attenuator, needing more clicks for the same arc sweep, is put into practice.  This is exactly what I think you need, although the reasons why you need it are vague.  Could be some of the resistors going bad you mentioned earlier.  I still wouldn't rule out the VCaps as a possible cause, though.

You need to discuss it with Steve, just to be sure. There must be a reason why he disaproves the VCaps in the Mini Torii.  Over and out! Smiley
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Les Lammers
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Re: Mini Torii SE Amplifier
Reply #174 - 04/08/12 at 02:12:48
 
It is not the V-caps. The info on the Goldpoint page is correct. High gain amp, hgh ivoltage source and efficient speakers with no xover
equals hair trigger volume control.

However, before I did anything I would wait for Steve's reply. I think he will have a solution.
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Fireblade
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Re: Mini Torii SE Amplifier
Reply #175 - 04/08/12 at 02:59:00
 
So how do you explain the paradox (most people under similar conditions without an unmanageable gain problem)?  Of course the Goldpoint page is correct.  The issue is why it happens so dramatically in Radushka's case, relative to the rest of M-T owners.
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Les Lammers
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Re: Mini Torii SE Amplifier
Reply #176 - 04/08/12 at 03:00:17
 
Floridaboy

What I mentioned about this are the most usual ways of dealing with excessive gain....which I have dealt with over twenty years and from designing and building some of my own amps.  But doubtless you are right that Decware knows more about there products than anyone!  We are  just sharing ideas, which in my view makes for beneficial discussion.

He could also even use a variable L pad on his driver, selected to match the impedance of the same... But yuk, it would be better to take care of it at the line level, if by no other way than by putting a preamp between DAC and amp.  
 

Erik, I understand the sharing of ideas and I don't have any audio ego.
I hope the solution is simple. Now I am curious about how the high gain is achieved in the amp.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #177 - 04/08/12 at 03:21:51
 
here is what the tech at Goldpoint told me (he seems to think the output impedance of the dac is overboard):

Raduschka,
Lower attenuator impedance is not directly related to better high frequency response necessarily.
In your case, however, it could be borderline. That's why we don't generally recommend stepped
attenuators above 100K for use with tube gear. But, you have an additional problem, and that is
the output impedance of your signal source is way too high, unfortunately. It should be below a
few 100 Ohms.

However, to start off with fixing up your system there, you either have to install preattenuation
(a 2-resistor voltage divider) or reduce the gain in your amplifier. In that way, the stepped attenuator
will be adjusted to work with your system. Instructions on how to do this are on the Goldpoint
web site. Find it on the DIY page. Handle this first. If you still have high frequency roll-off,
which you shouldn't, we can discuss alternatives at that point. But, it is unlikely that even with
1.3K signal source output impedance that you're getting high frequency roll-off.

Arn Roatcap
Goldpoint Level Controls
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #178 - 04/08/12 at 03:23:57
 
here is what i got from Eli Duttman od DIYaudio (I will need translation Smiley :

Applying the 1:10 rule of thumb to the DAC's O/P impedance of 1.3 KOhms tells us that 15 KOhms or a bit less will be adequate.  You really need to employ a padding resistor in series with each control to tame the "hair trigger" issue.  My seat of the pants guess is that a 4.7 KOhm metal film part in series with a 10 KOhm log. taper control will do the job.  You can always increase the padding value, if control is still "touchy".

No way do I spend big money on those Goldpoint attenuators.  Hot molded carbon controls made by PEC of Canada cost lots less and certainly have a "warmer" sonic signature.  PEC controls are milspec tough and also reasonably priced.  A pair of DigiKey stock # KA1031S28-ND is what I suggest you use.

BTW, hold the interconnect cable capacitance between DAC and amp down.
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Raduschka
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Re: Mini Torii SE Amplifier
Reply #179 - 04/08/12 at 03:39:54
 
I would guess Floridaboy and Goldpoint have a point: High gain amp, hgh ivoltage source and efficient speakers with no xover
equals hair trigger volume control. Plus the output Z seems to be high, not that I really understand , but....
Once again, I was warned about the Vcaps adding gain and I did not notice any subjective difference, if that matters to anyone. This si no way a new issue, brought about by the Vcaps. And I also do not know how 'extreme' it is. Maybe it 'appears' extreme.
I am torn between all the interesting reviews of expensive attenuators and the cold showers of  savy people who suggest cheap parts.
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erik2a3
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Re: Mini Torii SE Amplifier
Reply #180 - 04/08/12 at 16:08:59
 
Floridaboy: Noted, and I understand where you are coming from.

Raduscha: to explain the high frequency issue related to lower value potentiometers would take a long time.  I think, however, that you got sound (truly not an intended pun!) advice from Eli and elswhere.  The in-line attenuator I mentioned works very much the same.  And as I mentioned too, and of course just my opinion, that the output impedance of your DAC is just a wee bit high, but not at all unreasonably so.  Short ICs can be important in such cases, particulalrly in instances of higher output impedances in conjunction with passive volume controls, regardless of how much the cost or stepped or not.  This is because higher output Z has difficulty driving the capacitance associated with long lengths if cable.  So keeping them as ASAP (as short as possible  ::) is better than not.

The reason that your Vcaps might very mildly increased gain is because that type of cap, vs say an electrolytic (which, believe is or not, can be found in interstage coulping positions) is that they have rather low ESR (Equivalent Series Resistance).  Remeber awhile back or in an email I mentioned that even capacitors have elements of inductance and resistance? This is to what I was referring.

Here is something you can try: get a small box of some kind to use as a chassis.  Cheap plastic would be fine.  Drill four holes that are correctly sized for cheap RCA jacks.  Install the jacks.  Drill another hole to fit the shaft of a cheap potentiometer -- say 10k to start with, either linear or audio taper.  Install the volume control.  Do you know how to wire a pot as far as input, wiper (output) and ground?  One set of RCAs will be for the input.  The wiper, center lug on each section of a stereo control is the output in a standard configuration (there are different ways to wire a pot, including a shunt type of contro -- I'll talk about later, it's an idea that may help in ypur case, and have the added benefit of a potentially better sounding pot) will be connected to the output jacks.  Connect the grounds and potentiometer ground.  And run leads from the center of the input RCAs to the input lugs of the colume control.  And what you have just made is a very cheapmbut effective passive volume control.  Goldpointmsells these for a few hundred dollars.

Now plug your DAC into the input RCAs of the box, and the outputs of the box to the inputs of the mini torii.  What you end up with is what I suggested could be done using those two remaining holes in the mini torii, which is essentially a passive preamp built into the chassis. Trymit first the way I mentioned above.  Please, if I may say this, don't overly rebuild your amp right now.  Deal with the gain issues first, and then, perhaps do other modifications you might be interested in.  If too much is done too fast, you can end up feeling exasperated.  Ask me how I know! Undecided. What all of this is really sort of a variable rather than fixed voltage divider.  And apologies for spelling errors.  I have typed all of this very quickly.

Another note: the 6y6 may be my favorite tube with this amp.  It does run quite warm, but I knew that would be the case, as Florida boy also mentioned.  My dad, who is truly experienced in vacuum tube radio electronics often laughs at what I interpret as being hot as far as power supplly components go.  Moreover, I have a very good but low powered OTL amp that runs in single ended class A that will literally sizzle of I dampen my finger and touch the chassis.  Very heavy currents run through the chassis and the heatmis actually normal.  If you are not sure about anything I've written let me know and I'll explain it.
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Re: Mini Torii SE Amplifier
Reply #181 - 04/08/12 at 16:48:07
 
Erik and all,

This has been a good discussion for sure.  We all may have some small issues with this amp due to our associated components and it is impossible for Deware to make a 'one size fits all ' product. Since this amp is built to order it may be easy for Steve to reduce the gain a bit.

Fireblade,

I am not going to get worked up over this and neither should you. JMHO. Tubes, capacitors, resistors etc. are quite subjective. There is no best...only what sounds best to you. Me? I don't care for Teflon caps or Tantalum resistors...but you may. Hope this makes sense.

What I want from this amp is a good all 'round music machine, musicality before the ultimate in transparency. I have had rigs that were so revealing that I could only listen to a small percentage of my CD's and I do not want to go there again.
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Re: Mini Torii SE Amplifier
Reply #182 - 04/08/12 at 18:14:34
 
FB,

I agree.  I just want to rule out potential shortcomings and prepare myself with possible solutions.  I won't be doing anything mod-wise until I hear it, totally broken-in, but these discussions help me learn more about its intricacies.  I don't know about you (with experience in these topics), but I want to learn as much as I can.  It's all part of the fun. Have a good listening! Smiley
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Re: Mini Torii SE Amplifier
Reply #183 - 04/08/12 at 18:37:48
 
Let me also explain my intentions further.  I have two weaknesses in relation to music appreciation: Classic Bebop jazz and classical music.  From classical, I enjoy both orchestral works and smaller ensemble works.  These three different source types pose correspondingly different demands on the audio gear.  I envision eventually having sorted out two or three different setup configurations, aimed at each of these genres, as to tap the potential from the gear in each case.

One way to enable this adaptive process, other than blind trial-and-error, is to learn about the amp's inner workings, tube rolling and other tweaks that may help me identify possible setting tradeoffs for each particular type of music.

I prefer this approach than the one many people choose, namely, buying different amps/speakers for each particular application.  I think you end up really familiarizing with your particular gear and it may be a more practical (and economical) approach.  One can also learn a lot in the process.

So let the arguments begin ...  ;)
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Re: Mini Torii SE Amplifier
Reply #184 - 04/08/12 at 19:32:29
 
I really enjoy the fact that all  of a sudden the forum topic lights up and draws so much attention and investment. It has been pretty dead for a while.
Myself I specialize in psychotherapy, but I keep wanting more from my sound system and feel claustrophobic when limited. I know some of you have been playing around with audio for decades and were able to come to conclusions, but I can only make my own mistakes and find my own taste. Right now I am amazed by transparency, and how new parts can reveal more of what is hidden on those cd's. So far the setup has remained very musical. Maybe if I overdo it I will know (from experience) what it means to have an overanalytical system.
Erik, I understand very well the idea of installing volume pots on the incoming signal, before the amp's atts. I know how to solder volume pots, although I don't know much in general. I work deductively in electronics, which oftentimes doesn't take me far and sometimes backfires. Literally Smiley
After all this discussion I must say that if a new attenuator offers me ONE single click that I can use I will be satisfied, as long as it sounds better than those I have now, which I do not trust particularly. The gain issue is secondary for me and now I know how to solve it, thanks to your collective efforts, thank you very much.
So for me the question still remains whether I should get an att of the same value as the one the MT comes with (100k) or lower (50k or even 25k), given my present setup.
As for the Vcaps, my observations so far are of the hesitant kind, which dwindle from day to day and I need more time to say for sure if the soundstage is really more fwd, or perhaps I need to reposition my speakers etc etc, or perhaps I hear more detail or who knows. One thing is clear though, the sound has changed and I hear strings, let us say, which really sound like strings, metallic or not, to a degree that gives me goose bumps. That is an uncontrovertible observation, compared to the ones I mentioned before.
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Re: Mini Torii SE Amplifier
Reply #185 - 04/08/12 at 20:17:16
 
soldered back in the 240k resistors (took out 2w kiwame) and voilà! The soundstage depth and focus are restored!!! Phew!
I had replaced the 2k7 resistors to the input tube (from vol.pot out) with 2w Shinkoh and there was a marked improvement in detail. May try a 0.5 watt shinkoh one day. Once again, no change in gain whatsoever, don't go thinking it appeared after my mods Smiley
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Re: Mini Torii SE Amplifier
Reply #186 - 04/08/12 at 20:39:16
 
Radu

I hope I didn't sound like I thought you didn't understand what to do.  I  just wanted to clarify what I might have written in the way of a lousy or poorly worded description.  And I of course I don't know your electronics ability.  Steve, by the way, has to be one of nicest guys in the business.  I have talked with many designers over the years, and Steve is down to earth and a gentleman.  I of course can't speak for him or anyone, but I think he would understand the urge to tweak and experiment.  That's how this amp came into being after all.

And good grief it makes sense to have only one system that does everything well, fireblade.  Very good sense, in fact.  I think of that sometimes when I look at the two pair of huge horns staring back at me from across the room.  I love what they both do very well but differently, though!

Anyway, all have a good Sunday with your firends and family.  You'll get this gain issue solved, Raduscha!
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Re: Mini Torii SE Amplifier
Reply #187 - 04/08/12 at 20:59:10
 
no  no Erik, where did you get that idea?? I just said that I knew how to solder volume pots, in direct response to your question: 'do you know how to solder volume pots?' Smiley  Imagine if I strated feeling offended everytime someone helping me out fails to guess what I can and cannot do.....
I do apprehend explaining to Steve how I improved his amp, hahahah  ...wait, I am really laughing...arf arf...
but I suppose he'll understand. Anyhow , I wrote to him and am waiting to see if he thinks it is a substantial email.
For now I am happy that the resistors I put back in are not the faulty ones and that my perfect holographic imaging is back!!!! I had definite treble rolloff with the 2watt Kiwame. Now I feel ready for good atts. Please Erik, tell me what value I should get, 50k or 100k?? Please please,
I am now going out to buy groceries. Just thaught you all needed to know that.
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Re: Mini Torii SE Amplifier
Reply #188 - 04/08/12 at 21:08:53
 
" but I can only make my own mistakes and find my own taste. Right now I am amazed by transparency, and how new parts can reveal more of what is hidden on those cd's. So far the setup has remained very musical. Maybe if I overdo it I will know (from experience) what it means to have an overanalytical system."

It is a journey and only you can decide when and where to stop.

Here is a tip: Go slow with changes and give each one a good listening to before moving forward.
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Re: Mini Torii SE Amplifier
Reply #189 - 04/08/12 at 21:40:10
 
Wait ....  What 240k resistors had you removed?  Did you replace them with like values of some other brand?

I just got back from buyong groceries, and at mymdear wife's request, some paper towels!  You can never have too many paper towels!
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Re: Mini Torii SE Amplifier
Reply #190 - 04/08/12 at 21:56:08
 
I had replaced the 240k resistor btw pins 1 and 6 with a 2watt kiwame. I had replaced 2 pairs of resistors at the same time and lost the highs but solved a nagging right channel crackle and hiss problem. I put back the original 240k and  got back my dignity. And realized at the same time that the bad resistor was one of the 47k!!

The 47 k I have installed now are 2 watt audionotes. The 2 watt is overkill and possibly a wrong decision, will have to swap with 0.5 watters. But as is it sounds great too.
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Re: Mini Torii SE Amplifier
Reply #191 - 04/08/12 at 21:57:45
 
I love my girlfriend too Erik. She confirmed that the sound got back on track. I always ask her to listen to the same song, 'some days are better than others' on zooropa. The only U2 album I like.
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Re: Mini Torii SE Amplifier
Reply #192 - 04/08/12 at 22:00:45
 
Fireblade wrote on 04/08/12 at 18:37:48:
Let me also explain my intentions further.  I have two weaknesses in relation to music appreciation: Classic Bebop jazz and classical music.  From classical, I enjoy both orchestral works and smaller ensemble works.  These three different source types pose correspondingly different demands on the audio gear.  I envision eventually having sorted out two or three different setup configurations, aimed at each of these genres, as to tap the potential from the gear in each case.

One way to enable this adaptive process, other than blind trial-and-error, is to learn about the amp's inner workings, tube rolling and other tweaks that may help me identify possible setting tradeoffs for each particular type of music.

I prefer this approach than the one many people choose, namely, buying different amps/speakers for each particular application.  I think you end up really familiarizing with your particular gear and it may be a more practical (and economical) approach.  One can also learn a lot in the process.

So let the arguments begin ...  ;)


FB, I always chuckle when you say "classic bebop" because on jazz boards there are all kinds of arguments of nomenclature. "Classic jazz" is the New Orleans tradition and the 40's revival and the "Chicago Sound." "Bebop" is "modern jazz", and to call it "classic" can only make sense in this classificational world of jazz bulletin boards in referring to the very first years of modern jazz and its originators, that is "classic bebop" would just be the jam sessions at Minton's (some recordings) and so many other places that weren't recorded because of the "recording ban," and could maybe be stretched to include the first groups of Charlie Parker, Dizzy Gillespie, the Coleman Hawkins group with boppers, the short-lived Eckstine big band, etc.

Anyway, "classic bebop" is close to nonsense in that world! Gives me big chuckles to read. Thanks.

My real post is to say I commend your intentions. I hope you have on order the amp that will be THE amp for YOUR speakers and you can start right in on tuning the sound. My observation: I think you may discover as I have that there's ONE assemblage of tubes that is right for BOTH your jazz and classical recordings. One group that makes the amp sing it's unique song with the source material. I've found one that I can just pop in and spin rock, jazz, classical, Brazilian, blues, what's in my voluminous shelving. That's my prediction: you'll find one group of tubes that sets the amp free to show you what's on all the discs.
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Re: Mini Torii SE Amplifier
Reply #193 - 04/08/12 at 22:21:28
 
For the first time we are now testing with 15 ohm silver coil Lowther PM2As.  Tube compliment for the mini torii are 12at7 and 6y6.  This combination is just amazing....
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Re: Mini Torii SE Amplifier
Reply #194 - 04/08/12 at 23:32:44
 
Erik, I tested 6L6 tubes in my MT and did not like the presentation one bit. Things were pretty much out of focus, although the bass was great and everything sounded somewhat fuzzy. Someone on the forum told me that it sounded pretty much like what I could expect from 6l6's. Could you please resume in a nutshell what is specific to the 6y6 in the MT, as compared to the 6v6?
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Re: Mini Torii SE Amplifier
Reply #195 - 04/09/12 at 00:31:40
 
Lon,

As you should know, defining Bebop is already a very difficult task.  The only sure characteristic is the free improvisation license to all  musicians.  Within this very obscure and vague definition, there are myriads of styles possible.  I call classic Bebop, just as an example, the earlier works by Miles Davis, not the middle or final ones from his prolific and varied career.

I call Classic Bebop everything that encompasses music from Charlie Parker all the way up to earlier Hard Bop. Period.  So there you have my own definition of Classic Bebop.  It usually consists of music from the 50's and 60's, but extends up to the 70's in some traditional musicians (it's a style, not a chronological issue).  Also, the blues are very much imbedded in this style.

It is a particular style ideal for trios, quartets, quintets and even sextets, and usually combines solos from wind instruments (trumpet and sax, for example) or striing instruments (guitar) or vibraphone, in most cases interacting with piano.  Piano trios are the most basic ensembles for this particular style.  Although bass and drums are permanent side instruments in these arrangements, the Classic Bebop structure implies sections of the song including bass and drum solos, respectively, usually interacting with wind or piano leads.

Being very independent in my way of thinking and perceiving life, I could not care less about how other people 'classify' my description of this sub-component of jazz.  What is important for me to enjoy is the virtuosistic improvisation playing around a simple melody, that is used only as a vague reference throughout the session.  I admire musicianship at this level, and I'm also very taken by the simple yet moving effect of the bass rhythm throughout this musical structure.

In my personal appreciation, usually older or more modern attempts or interpretations are seldom to my liking, simply because they lack this acquired cultural ability to demostrate full command of their instruments around a simple melodic line, with great good taste and never boringly.  It is virtuosism, not showmanship.  For example, Charlie Parker was sometimes contaminated by this interest of showing off those wonderfull skills, sometimes to the detriment of the melodic structure.  Mostly, though, the man was unbelievable!

In my appreciation, the best exponents of what I call Classic Bebop are (in no particular order): Chet Baker, Art Pepper, Ben Webster, Charlie Parker, Miles Davis, Stan Getz, art Farmer, Coleman Hawkins, Gene Ammons, Gerry Mulligan, Duke Jordan, the great Bill Evans, Jim Hall, Jimmy Cobb, Lester Young, Roy Hargrove (modern old-style), Lionel Hampton, Cannonball Adderley, Arturo Sandoval, Benny Carter, Brad Mehldau (modern-old style), Bud Powell, Keith Jarret, Dave Brubeck, the great Oscar Peterson, Paul Desmond (by himself), Sonny Stitt, Sonny Rollins, Sonny Clark, Phil Woods, Duke Ellington, Freddy Hubbard, Dizzy Gillespie, Grant Green, Kenny Burrell, Johnny Hodges ... and countless others I can't remember just now.

So, there! You can chuckle all you want, Lon, this is my own definition of the best jazz style I've come to appreciate, and which has offered me innumerable hours of sheer listening pleasure.

Have a nice listening session ...
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Re: Mini Torii SE Amplifier
Reply #196 - 04/09/12 at 00:54:32
 
Lon,

Regarding your prediction about a fixed set of tubes handling all music genres, I hope you got that one right.  It would be much easier to have a fixed set and know that the sound is relatively the best possible for the particular setting ...  Let's keep our fingers crossed, we'll see.
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Re: Mini Torii SE Amplifier
Reply #197 - 04/09/12 at 00:55:54
 
FB, I love that stuff too, and the swing that came before it and the classic jazz that came before that and much that came beyond.

Sometimes when you talk to others about your interests you have to concede to nomenclature to avoid confusion. On my own I can call almost anything whatever I want to. But when I communicate with others there are some common touchstones I have to reference.

Most of what you are calling "classic bebop" I'd simply call "bebop" and would be called that on the boards.  Some of it more like swing, hard bop or perhaps even "modal jazz." Realistically, it could all be called "modern jazz."

It doesn't matter unless you're conversing in a community, which you aren't. Whatever it's called we love the music. I wasn't chuckling at you. I was chuckling at the attitudes of some of the posters I know well at your definition were you to proffer it in their little kingdoms. They don't matter, but they can be entertaining to me. I'm sort of a closet nihilist.

Have a fun evening. I'm hitting a few backroads.
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Re: Mini Torii SE Amplifier
Reply #198 - 04/09/12 at 01:05:41
 
Regarding the tubes: I use as a major reference to the basic sound for my systems recordings that I made in my then garage apartment of bands I rehearsed with and performed with and recorded rehearsals and demo tracks for. I used the same microphones, the same tape deck, and the same space for four different groups of musicians that included acoustic and electronic percussion over several groups, electric and acoustic guitars and basses and keyboards over several groups, vocalists and reed players and one crazy trumpeter over several groups. I know these recordings pretty darned well and the room and people and I myself participate in the music-making. It gives me a good reference. In all my tube systems I've been able to find a tube set that will represent realistically what I feel is on both the electric instrument material, the acoustic instrument material, and the material with a mix of both acoustic and instrumental material. When I get this set established, I can feel confident that my purchased recordings will be represented pretty realistically.

I therefore really believe it's possible, and will be interested to see if you discover this too in time.
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Re: Mini Torii SE Amplifier
Reply #199 - 04/09/12 at 03:10:19
 
Lon,

I did not think you were laughing at me.  And, to some extent, I agree we all need some conventionalisms.  But, I would argue that concept does not apply to this particular topic, as it is very subjective and full of inconsistencies.  I do agree the general term should be Bebop, but I'm always afraid of conveying a too open compass by that definition, as I don't really like a good portion of the music that may be included under this more general term.

Regarding the fine-tunning, I will also select specific reference material I'm quite familiar with, in comparing settings when the time comes.

I haven't been riding much lately, as weather here has changed already into frequent, randomly distributed heavy raining.  I usually can predict a few hours of dry weather very early in the morning, but not after that.  I think I need to change my schedules very soon!  8-)

Take care now ...
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