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How come only 3 tubes on the "DIY" kit? (Read 5118 times)
TubeNut
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How come only 3 tubes on the "DIY" kit?
04/02/08 at 01:10:13
 
I must have missed something somewhere. It says that the DIY kit has the same circuitry as the original Zen SE84C but it only has 3 tubes instead of 4. If the circuitry was modified to accept only 3 tubes then it isn't the same circuitry as the original Zen SE84C. Stupid me, I was so excited about having one of these DIY kits that I forgot to count the tubes. I feel that an explanation is needed here. After thinking a bit more, maybe the "original" Zen was designed many years ago, and at THAT time it only had 3 tubes. But still, that's misleading because one would think that they would get the DIY kit designed just like the "Zen of Today" to get all that fine sound...I feel cheated and like a "Tube Slut"...I'm really disappointed, Steve.
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'65 Fisher FM-100C Tuner-Linn Sondek LP12 TT w/Origin Live Silver Tonearm & Ortofon X5-MC Cartridge-Decware Mini Torii II-Anti-Cable IC's & Speaker cables-VH Audio Flavor #2 Power Cord-1975 Altec-Lansing Model 874A Segovia speakers-1974 Marantz Imperial 6G speaker
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DaveCan
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Re: How come only 3 tubes on the "DIY" kit?
Reply #1 - 04/02/08 at 01:26:23
 
 It looks like it clearly shows 3 tubes to me on the info for it, plus it uses a circuit board that the other amps don't.. I'm not an electronics expert but I'd say it's only voiced to the original as stated, but not the same build as there is one less tube and the circuit board etc...  Looks to me to have SS rectification ? as thats the tube that seems to be missing, tube power and tube input.....    Dave Smiley
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« Last Edit: 04/02/08 at 01:33:01 by DaveCan »  
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TubeNut
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Re: How come only 3 tubes on the "DIY" kit?
Reply #2 - 04/02/08 at 02:07:52
 
Thanks Dave,
I didn't say in my first post that I'm no electronics expert...so let me say it now Smiley It just peeves me that the DIY kit isn't the same as the current SE84C(4 tubes) I believe that you're correct about the missing tube being the rectifier.
I suppose ss rectification is no big deal since you get the "tube sound" from the output transformers and tubes. Am I correct in assuming that? Still, you understand where I'm coming from, don't you. I didn't just jump over to Decware and buy the first amp I could find for a good price. I've been to at least 10 different sites selling kits and chose Decware because I really like Steve's philosophy and knowledge. I also read many reviews about his products and most were good. That's why I picked his kit. I just feel like I was misled into buying something. Like I said before..stupid me. I should have counted the tubes first. Thanks again.
John
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'65 Fisher FM-100C Tuner-Linn Sondek LP12 TT w/Origin Live Silver Tonearm & Ortofon X5-MC Cartridge-Decware Mini Torii II-Anti-Cable IC's & Speaker cables-VH Audio Flavor #2 Power Cord-1975 Altec-Lansing Model 874A Segovia speakers-1974 Marantz Imperial 6G speaker
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DaveCan
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Re: How come only 3 tubes on the "DIY" kit?
Reply #3 - 04/02/08 at 03:19:13
 
Hi John, The kit is quite new in this format, I think it only came online in the last few months.. I'm sure if you were to call Decware with your concerns all would work out ok in the end..  I would bet  this kit wouldn't be offered if it wasn't up to snuff with the Decware sound, and the price seems fair...  Hope all works out ok and if you build it, please let us all know your impressions of the build ,and most of all, the sound....             Dave Smiley
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« Last Edit: 04/02/08 at 03:20:19 by DaveCan »  
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Jason
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Re: How come only 3 tubes on the "DIY" kit?
Reply #4 - 04/02/08 at 15:30:32
 
I wouldn't worry about it too much.    Not all Decware amps have been tube rectified anyways.    Both the first version integrated and the first version Torii used SS rectifiers and they more than keep up with the rest of the lineup in performance.

Jason
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veryoldcat
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Re: How come only 3 tubes on the "DIY" kit?
Reply #5 - 04/03/08 at 03:39:19
 
The answer regarding the missing rectifier tube is, of course, the cost saving. I think the soldering experience is also simplified, as it cuts down on the amount of jumper wires going to tube socket pins.  

It also means you can't brag about the almost unobtainable nos Mullard GZ32's or other such expensive critters that you can't help but want, cuz it's so easy to take one out and plug another in.

I agree with Jason. The best sounding vintage tube amp I've EVER had is *hands down* the McIntosh MC-225, which used solid state rectification. Modern diodes are very high performers, sonically, so not to worry.

Karl




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SE84CS (vcapped), CSP, zbox, Dec685, ZP 1.0, Sota tt/Well-Tempered Arm/V15XMR, Parker 98's, Parker Audio *Power Chords*, cat 6 wires, OSX; a garage sale of other stuff...
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TubeNut
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Re: How come only 3 tubes on the "DIY" kit?
Reply #6 - 04/03/08 at 06:27:39
 
Thanks Jason and Karl for your input. I really do appreciate your comments. I'm new to tube amps as you can probably tell Smiley Anyway, my first kit was the Velleman K4040. My second kit was the Velleman K8021 Control amp(preamp with phono stage input) Both work perfectly. I took my time, and the instructions were very detailed and easy to follow. I had no problems whatsoever. The only tricky part was measuring and bending/soldering all of the LED's for the preamp inputs. God I love the sound from the tube amp!!! When I was a kid(1960's) my dad was building Heathkits. He had a AM/FM stereo tuner that used the green "Magic Eye" tube for tuning in the stations. He also built our first color TV which was also a Heathkit. When I first got the tube bug I was looking for Heathkits but sadly they no longer produce kits. What a shame. Karl, if you are indeed "veryold" you'll also remember the Knight kits as well. My dad built a shortwave radio from a Knight Kit. He worked for Ohmite Mfg. in Skokie, IL. He used to bring home alot of variable transformers...you know, the ones with the adjusting knob on them. We used them for light dimmers for our table lamps. I've still got one from way back when.
Anyway, enough of that...back to Decware stuff.
I've been really interested in getting a Decware amp, but the cost is just a bit out of my current budget, so I opted for the kit, which is very reasonably priced. I haven't started on it yet, but I have been studying the PCB layout comparing it to The other SE84C with the P2P wiring. The Kit is indeed an exact clone of the P2P amp, minus the rectifier tube and bias switch..and power switch. I've been considering buying an enclosure and try to build it P2P. This would be a challenge for me, but also alot of work. I'd need to buy some additional parts, and depending on how much I'd have to spend, would it really be worth it?? It's just too easy to buy something and plug it in. I really enjoy building stuff. I used to build RC planes, and I just loved it. Crashing them isn't cool though, especially after investing $1000.00+ for everything. Now my new love is tube amps. (champagne taste/beer pocketbook is what I have) When I eventually get this kit finished, I'll let you know how it went. Thanks again for your comments, and I will check out the McIntosh MC-225 amp that you were talking about Smiley  John(TubeNut)
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'65 Fisher FM-100C Tuner-Linn Sondek LP12 TT w/Origin Live Silver Tonearm & Ortofon X5-MC Cartridge-Decware Mini Torii II-Anti-Cable IC's & Speaker cables-VH Audio Flavor #2 Power Cord-1975 Altec-Lansing Model 874A Segovia speakers-1974 Marantz Imperial 6G speaker
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chrisby
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Re: How come only 3 tubes on the "DIY" kit?
Reply #7 - 04/08/08 at 20:30:12
 
A few random thoughts on this kit:

First of all, kudos to Steve for the considering it all, and subjecting himself to the gentle abuse in offering any Decware product based on a PCB.  ::)


I guess you could consider that the actual cost of the PCB in the kit is a very small percentage of the total parts cost, and that this could be the cheapest way to accumulate the iron (most particularly custom OPT)  and small parts, etc.

However, if trying to convert to tube rectification, or more importantly to a  P-t-P build, remember that the cost of new tube sockets (the supplied parts will be for PCB mount), terminal strips, wire, etc, etc. could  easily add another $50, not to mention the chassis.  It appears that the mains transformer is the same as used in the production amps, so no additional filament transformer would be required if considering the addition of tube rectifier - just the mechanical & safety logistics.  

As anyone who has attempted a clone of the Zen C amp (thanks to the very detailed schematics and build information contained on the site) will attest (you know who you are  :-X ) - the costs can certainly add up on a one-off build, not to mention escalate when you start tweaking with boutique parts.  

In an amplifier with a power supply as simple as the Zen (only 1 stage of RC filtering prior to the OPT tap), it's very hard to disguise the nature and flavor of the rectification.  There are numerous accounts of tuning the Zen C and Select's character by rolling the "big glass".

Intrepid DIYers who have experimented with SS rectification in their tube projects ( aloha, all y'all Bottleheads) will know that not all "Sand sounds the same", and that swapping diode types from the basic 1N4007 can elicit some interesting changes.    

Steve or others, - please feel free to correct me on the following:


Having been under the hood of a couple of Select amps in the past, my only concern with the current version of the kit is the substantial heat generated by the shared cathode bias resistor  (and the 1K in power supply)  .  It would appear it ships with a 5W "sandstone" component for the first, and Mills W/W for the second, and while these may be adequate for the attendant current draws, I can remember the aluminum heat sink version the Select getting more than warm enough to melt the glue attaching the cathode resistor to the underside of the painted chassis.  If not thermally sunk to a metal chassis component, I'd like to see these parts stood well above the PCB, well away from any heat sensitive materials (i.e. not at all near the "breadboard").

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« Last Edit: 04/08/08 at 20:51:47 by chrisby »  

you don't really believe everything you think, do ya?
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TubeNut
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Re: How come only 3 tubes on the "DIY" kit?
Reply #8 - 05/07/13 at 18:16:24
 
Undecided I guess I deserve a good bitch-slapping from the "Zen Master"...
All of my whining about the missing rectifier tube was unfounded, and at the time of that writing I was very green. A public apology to Steve is in order here. That little 2 watt ZKIT ROCKS! I prefer it over the Velleman K4040 PP kit that I also have...it has 8 EL34 tubes and it sounds good, but not as good as the little unassuming ZKIT amp! I'm playing LPs on a Linn LP12 with an Origin Live Silver tonearm, fitted with an Ortofon X5-MC(moving coil) cartridge. That feeds into the phono input of my Velleman K8021 Preamp, then to the ZKIT. My speakers are vintage Marantz Imperial 6-G's rated at 93% efficiency. I get PLENTY of volume from this setup. I'm using Anti-Cables for interconnects and speaker hookup. I'm thrilled with the sound! Simply amazing! Grin
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'65 Fisher FM-100C Tuner-Linn Sondek LP12 TT w/Origin Live Silver Tonearm & Ortofon X5-MC Cartridge-Decware Mini Torii II-Anti-Cable IC's & Speaker cables-VH Audio Flavor #2 Power Cord-1975 Altec-Lansing Model 874A Segovia speakers-1974 Marantz Imperial 6G speaker
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dank
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Re: How come only 3 tubes on the "DIY" kit?
Reply #9 - 05/07/13 at 22:20:19
 
By using 2 silicon diodes instead of a tube rectifier you eliminate probably the most failure prone component in the amp (the tube rectifier) and you gain about 30 to 50 volts in the power supply output (depending on which tube rectifier you are comparing to).  This translates into more power output from the Zkit1 and better reliability than the SE84.


Dan
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