Tube monoblock recommendations

[Big Dog RJ]

A power amp isn't that complicated a circuit, especially a tube one. You can get generic schematics from David Manley's book, I think it's called "The Vacuum Tube Logic Book" or something to that effect, if you can find a copy. If you wanted a soft start you could probably use the kit that Tubes4HiFi sells.

Personally, I wouldn't bother with the triode/pentode switch. When I tried the one on the M125's, ultralinear sounded way better than triode, and had more power to boot. I never thought about it again.

Very true!
Although this is more or less alongside personal preference... UL operation has the edge over triodes, especially when it comes to greater control. UL op has more of everything that triodes offer.

I think that triode option was initiated during the SET era, such that SET always sounded sweeter, and there was more of that mid-band bloom. So quite a number of tube gear were offering triodes as an option. However, in most cases, once UL configs were more enhanced in circuitry and design, nearly every owner preferred UL op. There are those who are totally committed to SET Class A but for that kind of amplification the speakers must be highly efficient with high sensitivity ratings. Definitely not suited for stats. It may play tunes but not optimally.

Cheers, RJ

 

[Lightloopy]

Very true!
Although this is more or less alongside personal preference... UL operation has the edge over triodes, especially when it comes to greater control. UL op has more of everything that triodes offer.

I think that triode option was initiated during the SET era, such that SET always sounded sweeter, and there was more of that mid-band bloom. So quite a number of tube gear were offering triodes as an option. However, in most cases, once UL configs were more enhanced in circuitry and design, nearly every owner preferred UL op. There are those who are totally committed to SET Class A but for that kind of amplification the speakers must be highly efficient with high sensitivity ratings. Definitely not suited for stats. It may play tunes but not optimally.

Cheers, RJ

Interesting, I listen to the VTL MB450's in triode most of the time with that lucious, organic midrange but when nobody's home watch out. Flip to tetrode, put on Charlie or Chilliwack and let them rock.

 

[Big Dog RJ]

Interesting, I listen to the VTL MB450's in triode most of the time with that lucious, organic midrange but when nobody's home watch out. Flip to tetrode, put on Charlie or Chilliwack and let them rock.

That's about right!

In Triode mode it's a glorious midrange, without a doubt! That's their signature attribute. Also listenable for endless hours... especially late night sessions. Then switch over to SET, and it gets even more seductive, draws you into the music. So again, a very highly personal preference to the music lover / audiophile.

The VTL MB450's have plenty of power on demand. They'll drive any load, no issues there whatsoever. The best thing about these high-powered tube amps is that even in Triode mode, it can still sound full of presence and detail, simply because there are a large bank of tubes. Then switch over to UL op, and look out charlie! The full presence factor, dynamic slam, drive and control takes on another dimension, it just shifts gears. That's a marvel to have this option based in one amplifier design. Many don't do this any longer because it's too costly, and only a handful offer fantastic UL or Triode Output operation. That's why I always say hold onto these precious tooob amps! They're certainly one of a kind.

Cheers, and enjoy those finest tooons!
Woof! RJ

 

[Robert D]

That's about right!

In Triode mode it's a glorious midrange, without a doubt! That's their signature attribute. Also listenable for endless hours... especially late night sessions. Then switch over to SET, and it gets even more seductive, draws you into the music. So again, a very highly personal preference to the music lover / audiophile.

The VTL MB450's have plenty of power on demand. They'll drive any load, no issues there whatsoever. The best thing about these high-powered tube amps is that even in Triode mode, it can still sound full of presence and detail, simply because there are a large bank of tubes. Then switch over to UL op, and look out charlie! The full presence factor, dynamic slam, drive and control takes on another dimension, it just shifts gears. That's a marvel to have this option based in one amplifier design. Many don't do this any longer because it's too costly, and only a handful offer fantastic UL or Triode Output operation. That's why I always say hold onto these precious tooob amps! They're certainly one of a kind.

Cheers, and enjoy those finest tooons!
Woof! RJ

Youre making me want one! I bet you were a very good salesman.

 

[Big Dog RJ]

Youre making me want one! I bet you were a very good salesman.

Ah! True.

In fact, I was to a certain extent. Many years ago in a galaxy far away... When I finished up my under-grad in Chicago (May of 98), I remember very clearly my Sales & Marketing research lecturer said one thing that was solid advice, "if you're planning on selling anything, just make sure that you would want to buy the item yourself!" The rest is very little effort if you sincerely believe in the item, it will sell. Quite simple really, if you don't believe in the item and it's pretty much a load of bollocks then it won't sell, and don't waste your time trying to sell it!

It's a funny ride indeed, from that year onwards after graduating, I worked in so many corporates as Sales & Marketing manager, some were great tenures and some were not so great. That statement he made is so damn true, and to come to think of it now, even with all the high-tech stuff, all the bells & whistles + gizmos, the bottom line is, if it really works it will sell! The rest is all fancy, take that to AI, it can't even figure out day between night!

Cheers matey, and enjoy those finest tooons
Woof! RJ

 

[Robert D]

Ah! True.

In fact, I was to a certain extent. Many years ago in a galaxy far away... When I finished up my under-grad in Chicago (May of 98), I remember very clearly my Sales & Marketing research lecturer said one thing that was solid advice, "if you're planning on selling anything, just make sure that you would want to buy the item yourself!" The rest is very little effort if you sincerely believe in the item, it will sell. Quite simple really, if you don't believe in the item and it's pretty much a load of bollocks then it won't sell, and don't waste your time trying to sell it!

It's a funny ride indeed, from that year onwards after graduating, I worked in so many corporates as Sales & Marketing manager, some were great tenures and some were not so great. That statement he made is so damn true, and to come to think of it now, even with all the high-tech stuff, all the bells & whistles + gizmos, the bottom line is, if it really works it will sell! The rest is all fancy, take that to AI, it can't even figure out day between night!

Cheers matey, and enjoy those finest tooons
Woof! RJ

Yes. That professor was right about if you believe in the product and would buy it for your own, it will sell. I sold cars for a short while and can totally understand that. We are buying a new Mazda car today, and the salesman is new there. He had been selling Subaru for many years successfully and said he left because he no longer believed that the cars were great.
I guess if you're a great actor you might pull it off, but I know I couldn't do that.
You're a young guy still. I graduated from college in 92!

 

[Steelhead]

Tubes Rule as our best ever tube girlfriend EveAnna Manley told me. Great outfit and you will hear from her personally when corresponding with the company

Yes listened to 9 watt SET monoblocks at a friends house with highly modified Altec VOT's and basshorns. Absolutely incredible.

Gotta have the juice though for Stats.

Having the ability to select high power push-pull or triode is a great feature. Even though I never switch them out of triode. Nice to know I can.

 

[Big Dog RJ]

Tubes Rule as our best ever tube girlfriend EveAnna Manley told me. Great outfit and you will hear from her personally when corresponding with the company

Yes listened to 9 watt SET monoblocks at a friends house with highly modified Altec VOT's and basshorns. Absolutely incredible.

Gotta have the juice though for Stats.

Having the ability to select high power push-pull or triode is a great feature. Even though I never switch them out of triode. Nice to know I can.

Stop the train!
Eve Anna Manley! The best of customer service! It doesn't get any better than her genuine correspondence directly with the customer. I'm not sure how she does it and how she manages the time... but her service and tech support is Outstanding! With a capital "O".

I owned their gear quite a while back... between 98 to about 2001/2. First started out with a vintage pair of VTL/ Manley REF350's. These were referred to as the Designer's Ref series, with David Manley's signature on the front panel. They were absolute power houses! From there onto the Neo 250's then the Neo 500's. This was just after VTL and Manley Labs split up and went their separate ways. Even during that time, I needed all sorts of parts, tubes, resistors, ceramic tube sockets, fuses, schematics, even trannies! Her service and tech support was first class! Even back then, I was still using conrad johnson gear, and their service was just as good. However, Eve Anne had that extra edge where she'd go the extra mile to get your gear upto spec. She believed in it!

Luke Manley also stands by his gear, and the newer VTL amplifiers are truly tops! So overall, any of these top tier makes, VTL, Manley Labs, CJ and ARC are real VFM. You can't go wrong with any of their gear. Legendary sound quality with Legendary people to back it up, and they do it with a passion!

Cheers to the all time tube classics! And I agree, tooobs rule!
Woofty woof'n! RJ

 

[Leporello]

There are those who are totally committed to SET Class A but for that kind of amplification the speakers must be highly efficient with high sensitivity ratings. Definitely not suited for stats.

Except possibly, original Quads.

 

[Big Dog RJ]

Except possibly, original Quads.

Original Quad ESL's... as in the ESL 57 or 63?
I had both but they were quite finicky. Under powered amps, in terms of low current & inadequate stable voltages, wouldn't do it. Then again, the bigger amplifiers would over-drive it, causing them to arc! Not a pretty sight, and would cause holes in the mylar diaphragms. The more these ESL's arced the closer they got to compete panel failure.

Then came the newer versions (made in China) absolute useless. 988, 989, 2805, 2905, and 2912. The outer design was quite good! Much better bracing, more solid structure, more weight (around 42kg, added stability) but that was about it. The internals were really poorly done. That move to China was Quads disaster! Anyway, that's a whiole different topic. I owned all those series of Quad ESL's. Although the ESL 63's had better panel protection from arcing, similar to the later versions, it had so many other flaws.

ML stats are way above the Quad ESL's in every design aspect, and thank goodness they're made in Canada! After having spent over 20grand on my last pair of 2912's and having them repaired numerous times, it doesn't leave any great impression once you go through this. ML stats OTOH, a completely different level.

Getting back to driving Quads with SET amps, well it depends on which type and make of SET. Not all of them were made equally good. Too many variables in SET design. The really good ones cost top dollar and they're really tops!

Cheers, RJ

 

[lowheat]

I concur with ttocs regarding the Latino monoblocks driving my CLS II's, except I didn't hear anything special about the soundstage compared to a good SS design. I've never experienced VTL's personally except at shows, but have Manley's book, where he boasts about the quality of his bifilar-wound transformers (I believe the 300's are of that era. Once a Gordon Holt favorite, which he used with Sound Lab ESL's). Transformers are going to make all the difference as far as keeping the effective impedance low, which you need for ESL's--both by what they introduce in impedance and by allowing more nfb while remaining stable. Worth checking out.

Personally, the idea of using one step-down transformer on the amp cascaded with a step-up transformer on the speakers grates on my engineering sensibilities. Now, using one low ratio step-up between the tube plates and ESL stators makes a lot of sense to me, but nobody has tried that to my knowledge, at least not commercially. Maybe I will one day. For now, I am thrilled with my Parasound JC-1 monoblocks.

Maybe you just need an EQ or tone controls for TV. For me, music is the whole reason for high end audio, and movies and TV just go along for the ride.

Personally, the idea of using one step-down transformer on the amp cascaded with a step-up transformer on the speakers grates on my engineering sensibilities.
I understand. Acoustat used to have a tube mono amp (probably made for them by someone else) that drove the electrostatic elements directly. I used a pair to drive the old Acoustat 2+2. But the thing is, these would be very old now, don't know who would service them, and if like everything else in high-end audio over the past decade, would probably cost a bazillion dollars. Buyers should be aware that extremely high voltages are involved, IIRC. Roger Modjeski admired them.

 

[john65b]

All this talk of direct driving ESL panels...no step down to step up transformers...search Sanders (Innersound, not ML) White Paper on direct driving ESL from plates of a EL34 tube amp...I have it somewhere, I will post when I find it...

But I bought a kit from a company in Germany (Shackman) that has direct drive amp PCBs for mono amps (ESL panel driven directly from output tube plates). Each channel consist of a pair of 12AX7 driving a quad of EL84 direct to panel. Since they are high pass only - 300hz and up, (a good thing as few ESLs can do LP correctly, and simplifies the hardware needed) - the bias voltage is only 900 volts, compared to 3900 and 5000 volts from CLS and Acoustat interfaces...

I have both PCBs populated and just need to find the power transformers (0-640v and 0-6.3v) and chassis, and hook it all up to my CLS panels.

The project has sat for years as I have been happy listening to my Quad ESL-2805 and Quicksilver 8417 monos (now in backroom / for sale, being replaced with Eminent Technolgy LFT-VI and Hypex NCore monos). Maybe I will finish this project...

 

[Big Dog RJ]

All this talk of direct driving ESL panels...no step down to step up transformers...search Sanders (Innersound, not ML) White Paper on direct driving ESL from plates of a EL34 tube amp...I have it somewhere, I will post when I find it...

But I bought a kit from a company in Germany (Shackman) that has direct drive amp PCBs for mono amps (ESL panel driven directly from output tube plates). Each channel consist of a pair of 12AX7 driving a quad of EL84 direct to panel. Since they are high pass only - 300hz and up, (a good thing as few ESLs can do LP correctly, and simplifies the hardware needed) - the bias voltage is only 900 volts, compared to 3900 and 5000 volts from CLS and Acoustat interfaces...

I have both PCBs populated and just need to find the power transformers (0-640v and 0-6.3v) and chassis, and hook it all up to my CLS panels.

The project has sat for years as I have been happy listening to my Quad ESL-2805 and Quicksilver 8417 monos (now in backroom / for sale, being replaced with Eminent Technolgy LFT-VI and Hypex NCore monos). Maybe I will finish this project...

Nice one on the ESL 2805's. If you can play these well without any hiccups... they're beautiful stats, full range. I had the 2805, 2905's, and 2912's, I guess for my bad luck either the QC chic or QC supervisor were on a smoke break, because none of those ESL's lasted the warranty. Multiple panel failures plus tranny failures on the 2905's. Now I use the CLX Art's, these are my final stats.

Certainly looks like the QC crew in China factory were closely monitoring your batch of Quads! Good on them
Cheers mate, do enjoy those finest tunes!
Woof! RJ

 

[lowheat]

All this talk of direct driving ESL panels...no step down to step up transformers...search Sanders (Innersound, not ML) White Paper on direct driving ESL from plates of a EL34 tube amp...I have it somewhere, I will post when I find it...

But I bought a kit from a company in Germany (Shackman) that has direct drive amp PCBs for mono amps (ESL panel driven directly from output tube plates). Each channel consist of a pair of 12AX7 driving a quad of EL84 direct to panel. Since they are high pass only - 300hz and up, (a good thing as few ESLs can do LP correctly, and simplifies the hardware needed) - the bias voltage is only 900 volts, compared to 3900 and 5000 volts from CLS and Acoustat interfaces...

I have both PCBs populated and just need to find the power transformers (0-640v and 0-6.3v) and chassis, and hook it all up to my CLS panels.

The project has sat for years as I have been happy listening to my Quad ESL-2805 and Quicksilver 8417 monos (now in backroom / for sale, being replaced with Eminent Technolgy LFT-VI and Hypex NCore monos). Maybe I will finish this project...

Where do you find tubes for the Quicksilver 8417? I am under the impression that the output tubes (GE 8417?) were discontinued ages ago.

 

[john65b]

Lowheat - I find 8417 tubes from friends at DIYAudio or Reverb. Every now and then from ebay. I stay with the more rare / reliable / better Sylvania (and Bogen labled) 8417... I always have the stipulation with seller that when received, I test on my tester....if not OK, I reserve the right to return them...Only really had to return one pair that failed the tester...I had about 16 of them years ago...down to about 8 - 10 now... As far as I am concerned, they are the best sounding and easiest to drive output tubes of that family of tubes (6L6 / KT88 / 6550 / EL34 etc), but like Quads, they are very delicate and cannot be abused... I admit, I get a bit nervous when I leave the room with them powered up as they can runaway quickly...no such concerns with other tubes or the SS amps...

As far as Quads, its simple. If you like to listen loud, the Quads are not for you. All you have to do is just drive them hard once, and you have the propensity of lifelong issues. It does not take much to break the stator away from matrix support (its an epoxy glued connection) on a large volume spike, which then allows the stator to encroach the diaphragm, arcing the panel, and leading to more issues. If Quad could ever better connect the matrix supports to stators so they can never come loose, they would be just as reliable as the ML or Acoustats, and be able to be driven harder...

I have had a few Quad ESLs... the 63, 988 and now the 2805...never had anything but panel issues (loose stators). I consider the interfaces to be very reliable...its just the panels...

 

[lowheat]

Lowheat - I find 8417 tubes from friends at DIYAudio or Reverb. Every now and then from ebay. I stay with the more rare / reliable / better Sylvania (and Bogen labled) 8417... I always have the stipulation with seller that when received, I test on my tester....if not OK, I reserve the right to return them...Only really had to return one pair that failed the tester...I had about 16 of them years ago...down to about 8 - 10 now... As far as I am concerned, they are the best sounding and easiest to drive output tubes of that family of tubes (6L6 / KT88 / 6550 / EL34 etc), but like Quads, they are very delicate and cannot be abused... I admit, I get a bit nervous when I leave the room with them powered up as they can runaway quickly...no such concerns with other tubes or the SS amps...

As far as Quads, its simple. If you like to listen loud, the Quads are not for you. All you have to do is just drive them hard once, and you have the propensity of lifelong issues. It does not take much to break the stator away from matrix support (its an epoxy glued connection) on a large volume spike, which then allows the stator to encroach the diaphragm, arcing the panel, and leading to more issues. If Quad could ever better connect the matrix supports to stators so they can never come loose, they would be just as reliable as the ML or Acoustats, and be able to be driven harder...

I have had a few Quad ESLs... the 63, 988 and now the 2805...never had anything but panel issues (loose stators). I consider the interfaces to be very reliable...its just the panels...

Thanks for the information re 8417.
As for Quads, it sounds like we have had very similar experiences. I started with 63s, had a few pairs, then went to 989s. Yes, I have had panel failures. Electrostatic Solutions has been a reliable and reasonable maintenance shop. But $$ are involved. I have lived with and loved Quads and also hated them for their fragility. But oh, the ESL 63--the first time I heard them, I almost fainted.

 

[Leporello]

Buyers should be aware that extremely high voltages are involved, IIRC. Roger Modjeski admired them.

Absolutely! for full range stats--still my favorites--you need kilovolts on the stators , hence on the tube plates . With ML stators all you've got between you and lethal voltage/current capacity is the coating on the stators. I'm not concerned about that with the CLS's as the bias supply is unlikely to be lethal, only like the annoying shock that you get when walking on a rug then touching a doorknob in winter (I'm still careful, though, when working inside the transformer/bias supply boxes). The plate supply of a transmitting tube can very definitely kill you.

With Acoustat, you had insulated wires inside Teflon grids (may have been fluorescent light diffusers, anyway DIHY versions used those), covered in clothe. A lot more between you and electrocution. Still, I would have been wary. Acoustat's amps used some kind of transmitting tubes driven by high voltage op amps (I have a service manual and schematic I will post if I find it). Joe Curcio, a frequent Audio Amateur/Glass Audio contributor (now all folded into AudioXpress) offered a mod he would do, which was probably more tube-o-phile friendly.

I still think the best compromise between an engineering nonsensical cascaded step down/step up would be one well designed transformer between the tube plates and stators. Someone would have to design and build them for me as I don't have the expertise for either.

 

[Leporello]

All this talk of direct driving ESL panels...no step down to step up transformers...search Sanders (Innersound, not ML) White Paper on direct driving ESL from plates of a EL34 tube amp...I have it somewhere, I will post when I find it...

Please do!

Speaking of Eminent Technology and unfinished projects, I have an ET-2 linear tracking air bearing tonearm I got on eBay years ago. Bought a new mounting board for it from SOTA. I trashed my last Sumiko Blue Point Special playing with it, bough a new one for my main setup and a cheap cartridge for tweaking with. Other events like eye problems (detached retina) intervened. One of these days. I guess one of my fears is I will get it set up and hate cueing records on it.

 

[john65b]

Leporello - Found it - from Audio Amateur 1976...if you choose to try - use discretion as very dangerous.