Many thanks Lon

Oh yes, I'm sold on my ZAMIGO set up so I have my PS Audio DSD, my Oppo UDP-205 and my Magnum Dynalab 90T SE tuner all connected via balanced cabling to the ZTPRE, the ZTPRE to the ZBIT (two stereo single-ended outputs on this one) and the ZBIT to the ZROCK2 with one output and now to the Taboo Mk IV for headphone use with the other, the ZROCK2 is connected to the Monoblocks.

I was able to run the amps from 3 til 8 and they kept opening up and sounding better. They are reminding me of the Torii Mk III in the sense of headroom they have (crazy, they seem louder and more powerful than the Taboo and they aren't!) and I think that's also in part because of the OA3 and OC2 tubes that they share with the Torii and also the treble cut circuit which allows me to get just the right treble I want as with the Toriis). And I can tell there is more tonal and dynamic detail, not highlighted detail, "enveloping" detail.

Sorry, I don't have a camera and don't do photos. I got my wife's camera out a bit ago to take photos of two components that I will soon put up for sale, and gosh, I'm no photographer.

The amps look exactly like those Juan (busterfree) posted and that are on the product page. . . except a little toggle and knob in a corner of each which is the treble cut circuit. Mine have the walnut bases. Love the elegant simplicity of the black top. . . The look is so close to the ZP3's but my ZP3 is a white top version.

Can't wait to do more listening today! And yes, I have to work on taxes this week as well. . . . .

I'm always confused by buying something and immediately changing everything about it.
In my mind, Steve voiced this amplifier over the last few months, taking his time in trying different things out, figuring out what he thought sounded right.
Does changing the tubes out really make it better, or just different?
Maybe I just don't have the "golden ears" or whatnot. I just trust Steve to sell me what I need.
I guess I'm funny that way.

Lon,

I couldn't be more pleased to hear your positive impressions of these new amps!  I didn't let them leave the building until they got me excited in my own listening room.  This is the fourth pair I think... and they are really consistent.  They have a certain "IT" that as soon as you hear it you know you are there.  So far each pair has sounded exactly the same and that's a really good thing because the sound is at the very top of the Zen Triode ladder, and the consistency gives me confidence.  Your impressions give me even more confidence as I've learned to trust your hearing over the years.

Also good to hear you feel the difference is justified even in a real world listening environment which the vast majority of audiophiles live in!

I admit I was worried. I tested them on the HR-1's for a day or so before they left and in my fairly dead room which is about -2dB from what it was before I put carpet in it, I felt somewhat robbed. I needed that 2dB. I knew it would fall right on the line at your place and I was uncertain as to which side of the wall Humpty would fall

You are right, they don't have more power than the Taboo. The reason they are creating more "usable power" can only be attributed to the speed. We have learned that density is a watt multiplier, and now we are learning that speed is also a watt multiplier.  Can you honestly imagine a 2 watt amplifier sound this complete...as if it were 10 or 20 watts?  It's crazy right?

God Bless you for choosing the Type 80 rectifier with adapter. If I could that would absolutely be my choice for the the stock rectifier for this amp. The 274B is still the best sounding in current production that's affordable. That said, a real type 80 globe rectifier is magical and highly recommended.

I have to almost laugh when I hear you describe the sound of the Taboo compared to your new un burned-in monos. The same thing happened to Joe and myself when after listening for several hours we put in the TORII JR and the sudden contrast created a comparator that suggested the same thing. It was the first time in Decware history I heard one of my own children sound a little off.

You and I both are in love with the Taboo MK4. It's so damn good. Even without lucid mode the pentode output stage and floating ground brings something to the table that is truly special. To make that sound, well, bad, is a real accomplishment don't you think?

Can't wait to see how these amps unravel your head in future posts to see if there are any parallels to my own euphoria!

Happy listening and God's speed.

Steve

One more add: I do really like the Type 80 rectifiers in these amps. . . not surprising as I have liked the 5Y3 types previously. I do have one "globe" Type 80, an Arcturus, but not a pair. I can't say I prefer the Arcturus to the RCA bottle-shaped. . . but I will target getting a pair of the "globe" type in the near future to give them a good comparison.

Thanks!

Thanks! Everything's sounding mighty fine right now as i wrap up my federal taxes. On to State. . . or maybe tomorrow for the state taxes. . . .

No not terribly expensive. Yes, they'll work in the CSP preamps (I have one in a CSP2+ right now) as well as the ZP3 and the Zen Amps . . . I have a pair of Tung-Sol bottle-shaped in my Torii Mk III as well. As a rule of thumb they're electrically pretty identical if not identical to the 5Y3 tube that followed them historically so any of the components that  use this tube will use the 80.

They are not very expensive. The oldest is the "Globe" shape which I have seen dated into the 'twenties. I have one of these, an Arcturus and it sounds pretty nice but a pair of 'fifties bottle-shaped sound better to me. I also have a pair of straight short RCA tubes that look a lot like the basic 5Y3 that sound pretty good. The globe shape, which are also known as 280 and 380, are often the most expensive in unused matched pairs as . . . well they're old. But there's good priced examples of all the types out there.

The converters are easy to get too. I have a pair of bakelite ones and also three porcelain and brass ones that Steve also seems to use that may sound a bit better and are more expensive. They certainly look nice!

Hi Lon.

Congrats on your new amps. Been reading about the upgrade and I’m seriously considering to ship my ordinary mono amps for this upgrade. Curious to learn if anyone who have had them updated could give some impressions before and after. It’s a lot money, but also about the only thing I spend money on... so I guess I’m going to do it sooner or later.

I have to say the ones I got isn’t exactly slow and boring either,

Hi Lon,

Congrats on the Monos!

I know it is a bit early to make comments on this, but is it possible to make a preliminary comparison between the UFO versus the 25th Anniversary upgrades as of yet?  Among the three Decware amps I have (SE84UFO, SE34I.2+ and TABOO mkIII), the one with the UFO transformers surpass anything I have listened to from Decware (including a TORII mkII and the early versions of SE84s) not by a hair, but by a huge margin.  In other words, the UFO upgrade improved the whole sound so significantly that I cannot even conceive if the sound can be improved any further at all!

After hearing all the hype about the 25th Ann. upgrade, I might still consider selling my SE84UFO and invest in an SE84UFO25.  One thing that I am not fully comfortable with is the number of tubes on that amp though.  With 7 tubes instead of 4, there are a total of 5 tubes to roll which makes the itch more painful than fun!  :)  You know I really like simplicity in my signal chain, so apart from using a preamp (maybe), I stay away from other additional components.  So I am also questioning myself re: if an amp having only input, output and rectifier tubes is complex enough already...

Best,

Alper

Alper,
Based on what I have read from Steve's commentary along the way, I would guess that tube rolling is not necessary and that burden can be avoided altogether. If this amp turns out as good as what Steve proclaims, right out of the box, as-is, will be a transformational experience.  

As far as the number of tubes in the 25th, two of the seven are voltage regulators and are not in the signal path.  Much of the additional complexity of this amp is in the power supply chain, not the signal path.  So, I would not consider the switch from your SE84UFO to the 25th as adding anything that would degrade the sound purity or otherwise get in the way of the recording.  Based on the position of the RCA inputs, it may be that from point-to-point, there is less in the way with this 25th than the SE84UFO.

Quote:


My amps are still burning in after the modification. I am still running my original tubes. I do not get to listen as often as I want, but these amps make me want to listen more often. I can get lost in the music. I have toe tapping experiences. It is great. This is with the stock tubes. I plan to roll tubes at some point.

While the amps went back home for modification, I listened to my SE84UFO with a $200 rectifier and $200 input tube in the same system. I enjoyed it but not as much as my SE84UFO3 with 25th mod with stock tubes.

The Monoblocks have hit the 100 hour mark of music playing through them . . .and boy do they sound awesome. . . .

I did some tube-rolling today. For a spell I preferred my oldest pair of RCA 5V4G bottle-shaped rectifiers, but I went back to the Tung-Sol Type 80s as the RCAs were just a bit too "spacey." I unseated the 6N5P. . . it's a fantastic tube but it was just a bit TOO fast for my system these days. . . I put in a pair of GE 6DJ8 "Smokies" that add just a little bit of shadow and body. It's just right right now. . . SV83 output tubes and Westinghouse (probably made by RCA) OA3s complete the complement.

Today I have heard little peeks of info that I never heard before on some of the music I've listened to, and the sound of DVR shows has been spooky. These amps ARE a step beyond their predecessors. . . they have a "hugeness" to them that certainly belies their 2.7 watts per channel, and they project a distinct atmosphere to slip into. . . I told my wife they were "moody" and she said that would make them a perfect match for me (BURN!) . . . . She likes their sound too, she hears that they are different. She thinks I'm lying when I tell her how powerful they actually are.

A few days ago in trying to find a way to describe these I found myself feeling as if I were the microphone. In some cases it seems as your ears are a single stereo microphone that is picking up all the sound. In a way this feels right because you seem to have bypassed all the other stages of the music and be that closer to the performances.

I also feel these will season further and open up more. Which is almost a scary thought.

Hi Jeff,

I just re-read your message quoted below.

"As far as the number of tubes in the 25th, two of the seven are voltage regulators and are not in the signal path.  Much of the additional complexity of this amp is in the power supply chain, not the signal path."

Do you happen to know if the upgrade with respect to the power supply chain contributes to the cleanliness of DC or it improves the headroom, or both.  If it is about cleanliness, I have Stein Music's "Inline Power 2" and Blacknoise's power filters on both of my systems, which increase the speed a lot and provides me with a much darker background.

Maybe Steve can chime in here as well!  :)

Best,

Alper

I have about 150 hours on the Monoblocks so far and they are sounding very "alive," opened up more than the first week.

I've a pretty good handle on the "signature" now having gone through tubes and also different gain settings on the amps and ZTPRE and ZBIT and also different modes and voltage etc. on the PS Audio P10. It's very interesting I can get about the same sound with a 6N5P and an OB3 as I can with a GE 6dJ8 and an OA3 with adjustments. It's sort of maddening how many different flavors I can evoke with this set up.

As far as the P10 I have my output voltage at 121 and with the current complement (GE 6Dj8 "Smokies" and GE OA3 and Tung-Sol Type 80 bottle shape and Svetlana SV83s) I am using the "High Regulation" mode as opposed to the "Low Distortion."

It is a real pain to reconfigure my preamp and ZBIT and ZROCK2 configuration so I have not tested the Monoblocks straight from the PS Audio DirectStream DAC either single-ended or with the ZBIT balanced. . . . I know from all my experience with these components and I am going to prefer, nay NEED, the ZTPRE and ZBIT and ZROCK2 in front of the amps to get this sound that I am loving. . . so I'm just listening that way.

The Monoblocks have become the most detailed amps I have ever had, and unlike some system configurations I've had in the past, the detail is not a fatiguing and off-putting thing, the detail is presented seamlessly across the frequency spectrum and interwoven in the imaging and stage presentation. I'm getting a bigger sound both in apparent loudness and stage width and depth than ever before. This "detail" extends into the dynamic realm and the music breathes and moves in an improved manner. I honestly feel fulfilled with these amps driving the HR-1s and as Steve has warned I find it very hard to stop listening. I keep trying to get more time in and so far Lucy hasn't been TOO annoyed. She thinks the amps are very nice and though she doesn't like the full orange glow of the OA3 tubes I've decided to build a complement around them because when watching Blu-ray or DVD or the DVR I can actually SEE the OA3s flash which means the low frequency information is causing distortion. . . except when it is very distorted I don't even notice the distortion, it's characteristics are so full and enveloping. . . . With the OA3 I think I get a bit more distortion, but I can also visually insure that the gain is low enough to not cause distortion.

I have these amps in a living-room/dining-room area and not a treated room, nor are they as far out into the room as I'd like--a concession to Lucy and her highly visual taste in living decor and furniture placement. Still I find the three dimensionality involving and the imaging very accurate. Those who live for sound stages and images floating in the air in a dedicated, treated room will love these amps.

Hope you get a chance to order soon Joe!

Wow, today I rolled in a pair of "super-cryo'd" 6N1P and the dynamics and sound staging have never been better. They're sticking in for a spell. . . .

This afternoon I removed the six 6N5P that I have in the ZTPRE and replaced them with six of the 6N1P that I got with the ZTPRE, red-tipped from Steve, and put a pair of supposedly '79 6N5P from ebay (matched pair far more expensive than the others I've bought, I burned them in about 100 hours in one of my CSP2+) in the Monoblocks. Wow. This is the warmest (without being muddy) and most dynamic (they're breaking the speed limit) combos yet! I have an Amperex 12AU7 in the ZROCK2. Note to self: don't change anything for a while!

JD,

Lucy and I are living in a paradise with a huge state wildlife preserve literally across the street from us and we see so many wonderful birds. An eagle dropped onto the frozen lake to eat a fish less than forty feet from us when we got married by the lake two years three months ago, that was something! And this year it's these two owls. We've seen one owl the last three years or so but this year two, and they've been around near every day since early last month.

So life is good for me, here with nature all around and with this amazing system to listen to. And with a loving wife and a good dog and my family not too far away.

Have a great weekend JD!

Well, poor Lucy was sick all weekend and Monday and Tuesday and was finally able to go to work this morning, so today the Monoblocks are on again. I believe they have reached that point of hours and use that they are going to change subtly over time but no more big changes, just seasoning.

And I'm very happy with the way they sound. I've driven myself a bit crazy the last week with tube rolling but I've found some great complements and have pretty much settled on a set with one possible substitution: a pair of 6N5P in the inputs, a pair of SV83 in the outputs, a pair of Tung-Sol Type 80 rectifiers and either my trusty old pair of Arcturus bottle-shaped OB3 in the regulation spot or a newly-arrived pair of RCA short straight OB3 rectifiers. There's a clarity that the RCA offer that is quite nice, and they are fully glowing tubes so that distortion can be visible if I reach the limits, but the Arcturus have a warm mellowness that suits most of the music I listen to to a T. So the Arcturus may win out.

I'm back to running 6NP5 in the ZTPRE and loving that "signature"--and six 6N5P tubes I ordered from Decware should be arriving in a few days so I'll swap those in and the ebay bargain tubes out when the Decware tubes arrive.

These Monoblocks are continuing to knock my socks off and cause me to bemoan the limitations of my listening opportunities and the length of sessions. Amazing sound and I've never heard more detail more pleasantly and properly presented. I'll enjoy these as much as I can until the next adventure arrives, the 25th Anniversary version of the CSP3.

You're probably right about the DNA2. But. . . barring unforeseen circumstances. . . that would be a long way off as financially my next focus will be on a new kitchen and a garage with storage area. Going to be a while to swing that. In the meantime I have the amazing HR-1s and I love the heck out of them.

Hans, it's pretty much the same mods as I understand it, though done before the glass resistor was implemented. As there is only one output tube per chassis rather than the OD3 regulator tube to regulate both output tubes in the SE84UFO2-25, the Monoblocks each have one OC2 regulator tube to regulate its power tube, and this is located in a socket placed inside the chassis. Otherwise as I understand it the bypass capacitors for the various stages are very similar if not identical. Steve notes that the end results were very similar with a slight power difference in favor of the Monoblocks; he referred to the Monoblocks as slightly masculine, the single-chassis amp as slightly female in comparison.

I’m sorry if this has been covered.  What is the cost of the 25th anniversary mononlocks?

The cost is the standard cost of a pair plus $1360.

So, will you have a dedicated audio room when Lucinda retires? Or, does she not like your music playing due to her current illness?
I had to have a dedicated room. My wife does not like to listen to most of what I play and after a few hours she used to ask I turn it off and give her a break. And, this was before I retired!

I've gotten to spend more time today with the Monoblocks than I have been able to for a week. The Sophia Electric Aqua 274B are coming along nicely and I've forgotten about tube-rolling rectifiers in the Monoblocks and am rolling rectifiers in the Taboos instead, different Type 80s, an Arcturus globe in the IV and a Tung-Sol bottle type in the III.

The sound of the Monoblocks still thrill me every time they warm up and bloom. With my P10 and ZROCK2 I can get all the body and heft that I got from the Torii Mk III which really surprises me each time. And also the big open sound is similar to the Torii but having that "wholesome" quality that SET delivers. And the detail in the sound. . . I can't say I'm hearing things I haven't before in familiar material, but I am hearing them differently, more "in context" I would say, more naturally as part of the that "wholeness" rather than a transient zooming out or an isolated pull on your attention.

I made one tube change today and it's been positive. I had been using my Arcturus OB3 and I really am convinced the OB3 is better than the OA3 for my system. The Arcturus are bottle shaped, and I have a pair of Sylvania that are bottle shaped as well, and I prefer the Arcturus by a few hairs.  I ordered a pair of small straight OB3s from Raytheon to try out and I'm using these today. I must say they added a bit more warmth and body and are perfect for the piano trio music I'm listening to. I'll keep playing with them. The only drawback: I thought they would glow violet . . . but they glow orange just like an OA3. Which is okay, I just had to look at them several times to verify they were marked OB3 . . . they're marked OB3a.

One change yesterday: I received in a pair of short straight OA3 labeled "CEI" which means they were built by someone else. Looking at them they could be GE, not sure. Anyway, installing them and letting them settle in. . .a little treble glare has dissipated and wow, there's another level of dynamics that none of the other OA3s have yet provided. I'm enjoying the pump and push when the music requests it.

There are so many subtle bits and pieces that a listener discovers with these Monoblocks. I know that as they season I'll have a wonderful audio journey.

You're probably right Joe. . . we'll see in a few weeks or so!

I'll keep posting impressions as they seem significant Randy. These Monoblocks really surprise me at how much they sound like the Toriis in important ways, though I know that the voltage regulation being so similar and the fact that I have a P10, ZBIT, ZTPRE and ZROCK2 in the system have a lot to do with that too. In a few weeks my CSP3-25 should be ready to ship too most likely and then we'll see what adding that to the chain will do. I have a feeling it will at the very least add 25th anniversary voodoo to my headphone listening!

I hope you can get focused on audio again soon and yes, think about these 25th Anniversary new-comers, I think they're game changers. . .

Hey Lon,

I'm not surprised that the 6085s gave you a more robust sound. My 10W 330B amp benefitted greatly when I plugged in the 6085s that you loaned me in place of the stock 12AU7s. Thank you for continuing to experiment and to take us all along with you. I'm really enjoying following Steve and your threads regarding this combination of amps and preamps. Somewhere down the line, I'll be wanting to experiment with them myself.

Randy

Isn’t a 6085 12 volts? How does a 12 volt tube work in a 6 volt circuit?

These 6085 work and present a very different perspective than the 6922/6N1P varieties. The sound is warmer and more compact, and sounds more like what I think of as "classic" vinyl sound, sound of 'seventies and 'eighties turntable/phono preamp combos I've lived with and heard. I really do enjoy those tubes in the complement for hi-res material. But I suspect that what ensues is hardly fully linear and the tube does not get really hot. A fun substitute to play with and hasn't harmed anything.

But the 6N5P are giving the best sound overall for transparency and openness with Redbook material. I'm back to using a pair of these, older and slightly different than others I've used, and they need more break in but sound very "lively," open and dynamic and detailed. I want more bass, and most likely more will fill in with a bit more time and some adjustments--in the meantime I've rolled in a pair of 'fifties RCA 5V4G rectifiers which to bring a bit more heft to the sound. Palomino and I have both been using another 6N5P pair that are excellent in our amps. I may end up going back to those. It's great to have options. . . and definitely great to have backup complements.

After a three day weekend (my wife stayed home "sick" Friday) of headphones I'm listening to the Monoblocks again and really enjoying the sound!

Oh boy these OD3 are really giving me a sonic shot in the arm that is a great pick me up. It's as if the low bass is untouched but any congestion or looseness in the mid and upper bass is removed, thus opening up further the midrange and giving a clear bell-like treble. Or more probably this is all just a further lowering of the noise floor. It sounds similar to the progressive upgrades of the PS Audio DirectStream DAC which are all about diminishing noise and are all audible and have similar effects.

Thanks again Juan. A new exciting element.

Right now I have an Amperex 6085 in the ZROCK2 and a pair in the Monoblocks. Really contributing to dynamics and clarity, which are both also accepting contributions from the Aqua 274B. Note to self: don't mess with things for a while and don't disregard this note as you usually do. . . . .

I'm eager to hear this and see how it works in my system as well. I have high hopes. . . and my high hopes have been justified the last few years. I'm eager to hear how it may improve my headphone listening almost as much as how it may influence the Monoblocks. I'll keep you posted.

Just my 2 cents from balancing with my "stepped" outputs on my CSP3 (they have ten steps but aren't true stepped attenuators).  I have to balance between steps since even steps don't give enough or give too much adjustment.  The stepped attenuators would seem like a good idea if everything (tubes, room, etc) are in balance but they might make perfect balance more difficult if you don't land on a step.  If that makes sense.

Thanks Archie and Lon for the input. I've never had much interest in stepped attenuators until now, considering the mono blocks. Gad to hear they are stock. Thinking it's time to pull the trigger on these amps

I posted this in the Review forum and an the Facebook page:

https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1529248494/0#0

Putting a 25th Anniversary Edition CSP3 in front of the Monoblocks has made a sit-up-and-notice-over-and-over-again improvement. And that may be the only exercise you'll engage in for some time, you'll be glued to your seat.

I managed to tear myself away to do a voltage regulation "shoot-off" yesterday and today. The Arcturus OB3 that I have won. At least for now. They are like holographic projectors in these Monoblocks with the CSP3.

I keep thinking "this disc is a real monster of a recording." And then I spin the next one and it draws me right in as well. I know why Steve is spending so much time listening and listening. His new theme song should be "It Could Happen to You." He wasn't entirely joking about the "you should get this setup when you retire" statement. You'll want to retire if you aren't. . . .

I'm using both. The signal path is DAC or Oppo UDP-205 or Magnum Dynalab 90T SE into the ZTPRE via balanced input to the ZBIT to the ZROCK2 to the new CSP3, then to the Monoblocks.

If I weren't using three balanced sources I am pretty sure I would be getting excellent sound from the new CSP3 alone. But the ZTPRE makes everything better, i already know that, and is adding to the total "magic." I'm sure a 25th anniversary mod to the ZTPRE would be excellent, but it's an amazing preamp as it is and I really am not sure I'd mess with it for my needs.

I've got a lot of components in the signal chain and in the way that I thought last century this would have given me the willies. Instead I am having the deep jollies. . . And the ZTPRE may be why I am enjoying a noise-free hum-free experience with all those components in line. . . .

I finally ordered 25th Anniversary SE84UFO3 Monoblocks with glass resistors, real walnut bases, and walnut knobs. Can't wait!!!

Well, since I last posted on this thread the Monoblocks have been seasoning and sounding better all the time. I wen from using both the CSP3-25 and the ZTPRE to just using the CSP3-25 and now just using the ZTPRE, which gives me full balanced input and output to my ZBIT for my three sources and great sound. And I have learned more fully how to adjust the gain on the entire system and maximize my headroom and get the frequency balance and dynamics I crave.

I've been rolling tubes and really find that the Amperex 7308 are not going anywhere, and neither are the Sophia Electric Aqua 274B. Lots of other complements possible, but I like those. And I've rolled output voltage regulation and these REALLY change the amp. I have fallen for the sound from 0D3W regulation tubes, and I have four "varieties" now: Tung-Sol, Raytheon, Sylvania and Chatham, and I prefer them in that order, though any and all work very well, with subtle, and not-so-subtle frequency balance changes the main differences.

These amps are amazing. I no longer have a Torii Mk III, sold them both, and don't miss them. These and my Taboo Mk III and Mk IV are the only ones I have left now, the Torii Mk II is also gone. Those Toriis are great amps, BUT I have fallen in love with the smaller output tubes and SET/SEP sound. (And even with my HR-1s I don't need more power at all). Just so immediate and also so immersive and involving.  I have my Taboo Mk IV at Decware now for 25th Anniversary upgrades. I have a feeling when it comes back I'll send in my Taboo Mk III for the same! These mods RULE.

Good news!

I don't set up to favor sound staging but yes those aspects are improved with the 25th Anniversary Monoblocks. Sound that draws you in would be how I would best describe the effect they produce. Especially with vinyl I've never heard more realistic playback. . . sound just seems natural and "solid" while still being fleet and dynamic.

Steve is rightfully proud of these milestone 25th Anniversary amps.

Excellent. I will soon almost have an all Anniversary mod signal path for digital when my modded ZROCK2 arrives tomorrow--only the ZTPRE will not have available mods, and eventually I think it will. (I'm no longer using a ZP3 for my vinyl playback, at the moment I'm using a PS Audio NuWave Phono Converter, which sounds amazing paired with the ZTPRE).

The listening life is so good, which makes the rest of life automatically better.

I'm loving these amps. As they season in, and as I learn more how to feed them best, I am getting amazing sound with many tube complements. It's like owning a closet full of amps in important ways.

Lately I have been using a particular pair of military 6N6P that I thought I might well have paid too much for at first. They were too thin and vague sounding for my first experience in the mono block but after a few weeks of more than satisfactory use in the Taboo Mk IV-25 and CSP3-25 in the second system, they really opened up.

In my main system now they are creating quite an experience. The OB3 is the best voltage regulator for the output tubes for them, and a particular old pair of RCA the best of those on hand (I tried OA3, OD3, OD3W and OC3W as well, the OB3 has the best overall sound and texture). I could still use a bit more bass, and will tailor the system to that end in the next few days. In comparison to the 6N5Ps from Steve that I am using in the ZTPRE and was using in the mono blocks these 6N6P have the focus that the Amperex 7308 bring to the table, but not the slight veil of warmth, and they have the spacious dynamics that the 5814A that I use in the ZROCK2s has in comparison to other 12AU7s. A win win for excellent recordings, and working well for the mediocre and below recordings that serve as the bulk of my collection.

I'm glad I tried them, originally prompted by an email from Johnny Slate who posts here. I'm leaving them in for a while. . . .

All is well here Johnny. . . Those Valvos are very good. I have three of them in my CSP2+ with the 25th Anniversary mods and they work so well there I just leave them alone.

Well, as Jeff and Scott have noted elsewhere on the forum it's hard to let sleeping dogs lie, and it never ends. . . .

In consolidating space (Lucy: "Do you really need all these tubes down here in this cabinet?" Me: "Yes, but they can be stored elsewhere.") I went through all my voltage regulation tubes and realized I had three pairs of OA3 tubes (some funky old RCA, a Westinghouse, and a GE) and as old RCAs have been working so well in the system lately I popped in the pair of RCA for the RCA OB3.

There was the last ounce of bass I was missing with a dribble of more treble grit than I wanted, so playing with the gain between source, preamp, ZBIT and amps. . . wow! Just great dynamic and clear sound with the frequency balance I was craving.

So I discovered yet another "amplifier" in my Monoblocks and will be enjoying this one I think for a while. (Let sleeping dogs lie Lon, let them lie! As I write this Fiona the dachshund is asleep next to me.)

I have two great systems right now, and the 25th Anniversary mods are making them be all they can be.

The CSP3 can add a LOT of gain so source hum could be amplified.  Check out post #12 in this thread:  https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1557427190/0#12  It gives voltages versus knob settings.  Also, Steve mentions input voltage limitations for the CSP3.

I've always prefered what the CSP3 brings but I'm currently bypassing my ZROCK2 more and more -- something I didn't think I'd ever do.

archie: Thanks for pointing me to the post. I knew i had read about this somewhere and havent found it back. I live in a 240v area, will this change anything?

I wrote about a hum, but by all means its not like a problem-problem, and I should say that its not caused by my source. It seems to come from the pre-amp itself.

About gain setting:
When I dont use the pre, max volume I can use on the monos are 1 or 2 oclock position, so I sort of landed on that as a "fixed" setting when adding pre to the chain, should this rather be set to max? Should I set the gainlevel so that i can turn to max on the mastervolume control?


Im more "concerned" that the pre-amp is a "vial" for the detail and transparency im getting without the pre. And i wanted to express that the upgrade really is a difference, and more so than i realised using the pre-amp.

I use a ZP3 and a Auralic Vega dac as source

I hope you can resolve the hum. The two times I have had hum with my CSP3 in the system the problem was not the CSP3. One time it was the fact that I had my cable tv DVR connected to the system. The hum was coming in on the coaxial cable itself. I put a filter in line and the hum went away. (Later when Time Warner was sold to Spectrum and Spectrum changed over the cable tech frowned on it and told me to take it out I did so. . . the hum had gone away). The second time it was a cable placement issue. I am not sure which power cable was next to an interconnect that caused the problem but I think that was the issue. I ended up dismantling my whole cable loom and re-routing things to more effectively isolate power and signal cables and the hum went away.

Though expensive, the 25th Anniversary mod to the CSP3 is transformative. It's good pre-mods, it's really great after.

I play around with the gain between my DAC, ZTPRE, ZROCK2 and CSP3 and input gain on my Monoblocks. I have the Monoblocks at about 3/4 volume, the ZROCK2 pretty pumped up, the CSP3 outputs about 60 percent, and the ZTPRE about 70 percent. Usually my DAC is at 100 but I sometimes knock it back 5 or 10 percent. I control master volume via the ZTPRE. I can get incredible sound playing about with these gain values.

Great Geno. Lots to be discovered with the CSP3 and its gain and the gain of other components.

There are lots of alternatives on eBay, here's one:

https://www.ebay.com/itm/Amptata-5Z3-274A-80-To-5U4G-GZ34-274B-5Y3-5AR4-Tube-Ada...

Another:
https://www.ebay.com/itm/1pc-Gold-WE274A-5Z3-80-TO-WE274B-5U4G-GZ34-5AR4-Tube-co...

Almost all I have seen are from China or Hong Kong, and you have a 14 to 20 day wait or so. I used to have an American source but I think they have dried up.

As for the input tubes . . . I hestitate to make specific recommendations because I have found that even the ROOM makes a difference--tubes I didn't prefer in my living room I prefer upstairs with the same system, and vice versa. You can use so many different types! I really like the Russian NOS tubes from Steve--if you are going to use 6N1P or 6N6P get them from Steve--it's a crapshoot otherwise out on the internet. Steve tests and matches his meticulously. You can use 6922, 7DJ8, so many more. This page I find to be a useful guide:

http://www.audiotubes.com/6dj8.htm

I've gone beyond the pale perhaps. I use 6N5P, 6N6P, 6SN7 with converters, 6085 with converters, tend to rotate these as the fancy strikes me. Lately the 6SN7 and 6085 have stuck.

Hi Lon, great read.  Sweet monoblocks for sure.  

May I ask, what input jacks are mounted on the chasis, and how many?

I'm curious if I can get 25th anniv monoblocks, each with an XLR input.  I prefer to avoid a ZBit or XLR-RCA adapter cables as described in "bridging into mono" in the owner's manual.

I have really been enjoying these amps over the years. Can't believe how much time has gone by.

I think I'm now ready to try out fuses. I've looked at the manual but still a bit unsure which replacement sizes I should get. 5x20mm 3 amp. 250v, 500v? slo blo, fast blo? I'm thinking I'll start with the purple quantum. Any advice on which size to order or other fuses I should consider?

Thank you, Lon! Just the information I was looking for.

It is astonishing really the great, full sound I get from these Monoblocks. The HR-1 are not the most efficient, but relatively efficient speakers, and the density that the preamps and the ZROCK2 give me are also an important factor.

I have occasionally thought about other amps, but I haven't the dollars to experiment, and I really just am so happy with the sound I have and love settling back into the music and the musical presentation.

Keep in mind Synergistic Research has buy 2 get one free offers for fuses through their dealer network a couple times each year. The Cable Company and VH Audio are both solid sellers.

HK