Tube monoblock recommendations

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

thomasmasi

Active member
Joined
Apr 15, 2023
Messages
40
Reaction score
17
Hello to all, I am looking for any opinions on what has worked well presently and in the past for you concerning monoblock tube amplifiers. I have a pair of Prodigy's with new panels that are broken in and driven by 2 Parasound A21 vertically biamped. The preamp is a Cambridge audio 851n that doubles as a preamp/dac. It sounds great but not were I would like it to be when I am watching television, the spoken voices are a little harse. The system is used for everything, music, television and movies. I have used the following monoblocks Primaluna, Cary, Antique sound labs and Music Reference RM9 mkii. I prefer monoblocks since I have one amplifier next to each speaker. My best sound came from a pair of Primaluna monoblocks running the panels and a pair of class d monoblocks driving the woofers. Has anyone tried specifically using VTL MB300 or MB450? I understand the age and difficulty of dealing with VTL. Also can anyone recommend a very qualified tube repair technician on the east coast preferably in florida. Lastly there is no room treatments and listening area is living room/ dining room 40 x 16 and speakers are in the 20 x 16 area corner. Thanks for any opinions Tom
 
I used Bob Latino M-125 mono tube amps for a couple years, but struggled with liking what they brought to the table vs a Krell solid state amp I was using prior to the tubes.

The M-125 amps had the best soundstage I ever witnessed! The absolute realism was astounding! But the frequency dropped off above 7-8kHz and was down by -4dB @ 10kHz from what it was at 7kHz.

I'm back to using a newer Krell and love it, but the soundstage is not like the tube monos. It's close, but I know the difference. But the Krell beats the tubes in the sparkle wars. By sparkle, I mean how lively the sound is in the upper ranges without any harshness, and the fact that I can actually hear those sounds vs the tube amps' diminishing output at those frequencies and masking those sounds.
 
Hello to all, I am looking for any opinions on what has worked well presently and in the past for you concerning monoblock tube amplifiers. I have a pair of Prodigy's with new panels that are broken in and driven by 2 Parasound A21 vertically biamped. The preamp is a Cambridge audio 851n that doubles as a preamp/dac. It sounds great but not were I would like it to be when I am watching television, the spoken voices are a little harse. The system is used for everything, music, television and movies. I have used the following monoblocks Primaluna, Cary, Antique sound labs and Music Reference RM9 mkii. I prefer monoblocks since I have one amplifier next to each speaker. My best sound came from a pair of Primaluna monoblocks running the panels and a pair of class d monoblocks driving the woofers. Has anyone tried specifically using VTL MB300 or MB450? I understand the age and difficulty of dealing with VTL. Also can anyone recommend a very qualified tube repair technician on the east coast preferably in florida. Lastly there is no room treatments and listening area is living room/ dining room 40 x 16 and speakers are in the 20 x 16 area corner. Thanks for any opinions Tom
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.
 
Just curious. Do you have a good center channel to match the Prodigys? 60% to 70% of the vocals and created center image is from the center channel for TV/video watching. Even though Prodigys are amazing speakers you would solve part of that with the center.

If you want better high end as you mentioned the way you want the tube amps plus my personal choice ARC would be some place to start.

Good luck, let us know how you progress in your search.

Brad
 
Just curious. Do you have a good center channel to match the Prodigys? 60% to 70% of the vocals and created center image is from the center channel for TV/video watching. Even though Prodigys are amazing speakers you would solve part of that with the center.

If you want better high end as you mentioned the way you want the tube amps plus my personal choice ARC would be some place to start.

Good luck, let us know how you progress in your search.

Brad
Exactly. I use a Focus center channel speaker and am very happy with it along with my Prodigies.
 
I used Bob Latino M-125 mono tube amps for a couple years, but struggled with liking what they brought to the table vs a Krell solid state amp I was using prior to the tubes.

The M-125 amps had the best soundstage I ever witnessed! The absolute realism was astounding! But the frequency dropped off above 7-8kHz and was down by -4dB @ 10kHz from what it was at 7kHz.

I'm back to using a newer Krell and love it, but the soundstage is not like the tube monos. It's close, but I know the difference. But the Krell beats the tubes in the sparkle wars. By sparkle, I mean how lively the sound is in the upper ranges without any harshness, and the fact that I can actually hear those sounds vs the tube amps' diminishing output at those frequencies and masking those sounds.
I used Bob Latino M-125 mono tube amps for a couple years, but struggled with liking what they brought to the table vs a Krell solid state amp I was using prior to the tubes.

The M-125 amps had the best soundstage I ever witnessed! The absolute realism was astounding! But the frequency dropped off above 7-8kHz and was down by -4dB @ 10kHz from what it was at 7kHz.

I'm back to using a newer Krell and love it, but the soundstage is not like the tube monos. It's close, but I know the difference. But the Krell beats the tubes in the sparkle wars. By sparkle, I mean how lively the sound is in the upper ranges without any harshness, and the fact that I can actually hear those sounds vs the tube amps' diminishing output at those frequencies and masking those sounds.
I might give the M-125's a shot and it might be fun doing the kit. I believe they have enough power to drive the panels. Since I already have a pair of D class amplifiers to drive the low end
I used Bob Latino M-125 mono tube amps for a couple years, but struggled with liking what they brought to the table vs a Krell solid state amp I was using prior to the tubes.

The M-125 amps had the best soundstage I ever witnessed! The absolute realism was astounding! But the frequency dropped off above 7-8kHz and was down by -4dB @ 10kHz from what it was at 7kHz.

I'm back to using a newer Krell and love it, but the soundstage is not like the tube monos. It's close, but I know the difference. But the Krell beats the tubes in the sparkle wars. By sparkle, I mean how lively the sound is in the upper ranges without any harshness, and the fact that I can actually hear those sounds vs the tube amps' diminishing output at those frequencies and masking those sounds.
I think I might give the M-125's a shot and it will be nice to do the kit if they are available and i have a bunch of tubes already. I probably will end up with monoblock tubes running the panels and my Audio Crafters Guild monos powering the woofers. I appreciate the feedback. Thanks Tom
 
Exactly. I use a Focus center channel speaker and am very happy with it along with my Prodigies.
Hello Robert, I am strictly running a 2 channel system. I am probably being a little too critical of the harshness because it is only on certain voices.
 
Just curious. Do you have a good center channel to match the Prodigys? 60% to 70% of the vocals and created center image is from the center channel for TV/video watching. Even though Prodigys are amazing speakers you would solve part of that with the center.

If you want better high end as you mentioned the way you want the tube amps plus my personal choice ARC would be some place to start.

Good luck, let us know how you progress in your search.

Brad
Hello Brad, no center channel just a 2 channel setup.
 
Hello Robert, I am strictly running a 2 channel system. I am probably being a little too critical of the harshness because it is only on certain voices.
ok.

I dont ever use mine in 2 channel except for music, so ive not noticed any harshness in voices on my Prodigy speakers.
 
I use two channel exclusively and no tv in my room (OK Boomer)

I use Manley 100/200's tube Monoblock's in triode to power my 15a's. Definitely no harshness with vocals at higher spl's. I sometimes go to 103-107db on rare occasions when trying to relive my youth and the Manley's just let it through and the logans sing. At more normal 80-90db levels just really really nice detail and soundstage.

Fell into tubes bliss a long time ago. Having the powered woofers is probably the reason for the ease of presentation.

The prodigy's would most likely need big tube Monoblock's to sing but in push-pull should be able to give you what you are chasing.

In any event, Happy Listening!
 
Roger that captain!

Yes, that's about right regarding the better tube gear designs but they're pricey. Those brands already trialed by Tom, some good and some not so good are based on a certain ordinary level of tube gear, with certain exceptions though as is the case with Prima Luna (real vfm!).

Take that a step further into higher grade designs of power supplies, higher current capacity and high voltage design, one that can control, drive and grip stats to their full potential, and we have; ARC, CJ, VTL, Manley Labs, Jadis, Ayon, of course the Classic Sonic Frontiers tube gear. These are not ordinary tube gear, they're very extraordinary and will effectively drive stats full range. I've owned, sold and demoed all of these makes, and have ended up with CJ. It's just my preference, that's all.

On another note: not all SS gear is designed the same either. There are many so called high powered amps that simply run out of steam, especially when driving stats. Stats possess a notorious impedence swing, this can range from 22 Ohms in the high range and as low as 0.7 Ohms, that's less than 1 Ohm! This happens in a blink of an eye... and this is what causes many SS designs to puff out (if poorly designed). Those that are well capable; Krell, Dan D's, Parasound, Bryston, Aragon, Michi, Jeff Rowland, Pass Labs, Classe, Vitus, Luxman, Accuphase and so on are really tops! Take this a level further and we have: Dartzeel, CH Precision, Solution, Aries Cerat, Lamm and so on... these are truly extraordinary and very pricey.

So it all depends on your finances and personal tastes, listening habits and most importantly how your speakers interact with your room. It's not all about just watts and power, it's high current and highly stable voltages that will get you across the line in driving stats efficiently.

Also keep in mind, the higher powered tube amps will obviously utilise more Output tubes because that's the way Class A circuits are designed. There are very high powered tube amps from both VTL and ARC, that use an array of tubes. This is costly! CJ also has similar configs in their previous tube gear, where each monoblock typically has at least 8 Output tubes in Ultra-linear config per channel. However, of lately CJ has put out their new ART series amplifiers. The ART300's use just 4 KT150's but are capable of 300w. This sort of high power you'll never use but the ART300's are an awe-inspiring experience when driving stats full range. CJ also has the ART108A's (160w Class A) but those have 8 KT88 tubes per channel. I had the chance to audition these fine monoblocks in July driving CLX's, it was beyond superb!!! Price tag also superb.
This is what I refer to as extraordinary.

Anyway, it all depends on your preferences, and budget, hope that helps.
Cheers, RJ
 
I use two channel exclusively and no tv in my room (OK Boomer)

I use Manley 100/200's tube Monoblock's in triode to power my 15a's. Definitely no harshness with vocals at higher spl's. I sometimes go to 103-107db on rare occasions when trying to relive my youth and the Manley's just let it through and the logans sing. At more normal 80-90db levels just really really nice detail and soundstage.

Fell into tubes bliss a long time ago. Having the powered woofers is probably the reason for the ease of presentation.

The prodigy's would most likely need big tube Monoblock's to sing but in push-pull should be able to give you what you are chasing.

In any event, Happy Listening!
I totally agree, I probably will end up with MB300 delux to run the panels. The only thing stopping me is finding a local repair shop or if I can get a schematic i would do the upgrades myself. I am a sucker for seeing that glow, this is why I am hell bent on the MB300's or maybe cary slam 100 or the Primaluna hp Monoblock's. Both the Cary's and the Primalunas I have owned and sold.
 
I use two channel exclusively and no tv in my room (OK Boomer)

I use Manley 100/200's tube Monoblock's in triode to power my 15a's. Definitely no harshness with vocals at higher spl's. I sometimes go to 103-107db on rare occasions when trying to relive my youth and the Manley's just let it through and the logans sing. At more normal 80-90db levels just really really nice detail and soundstage.

Fell into tubes bliss a long time ago. Having the powered woofers is probably the reason for the ease of presentation.

The prodigy's would most likely need big tube Monoblock's to sing but in push-pull should be able to give you what you are chasing.

In any event, Happy Listening!
I totally agree, I probably will end up with MB300 delux to run the panels. The only thing stopping me is finding a local repair shop or if I can get a schematic i would do the upgrades myself. I am a sucker for seeing that glow, this is why I am hell bent on the MB300's or maybe cary slam 100 or the Primaluna hp Monoblock's. Both the Cary's and the Primalunas I have owned and sold
 
M125 monoblocks from Tubes4HiFi are likely the most cost effective solution if you're looking for any decent power levels. I have a set myself that I used on my Aerius speakers.
 
I used VTL MB 250's Signature Triodes w/ SL3's for many years till the amps started having fits. I ended up with 11 A's and a Mcintosh MC1502 which has been great. I still missed the special sauce of the VTL's and got an early series VTL MB 450 and they are just amazing.
My buddy was able to tame the VTL 250's and has my SL3's. Always puts a smile on his face!
CJ also highly respected w/ ESL's Good luck
 
I am looking at 2 pairs of MB300's, both have had some upgrades. One has the soft start done and the other has the triode tetode switch. I am leaning towards the one with the soft start since that upgrade is more expensive. Neither has the b+ fuse upgrade. The switch and the b+ is something I believe I can do if I can get a hold of a schematic which is must before I consider purchasing a 35 plus year old amplifiers. Thank you you're response because it was very insightful. Thanks again
 
M125 monoblocks from Tubes4HiFi are likely the most cost effective solution if you're looking for any decent power levels. I have a set myself that I used on my Aerius speakers.
Hey Brandon, thanks for the response. The more I thought about it the M125 look great but I am leaning towards the MB300. Don't laugh but hopefully the VTL's will be my last amplifiers. Going on 42 years of this audio quest!
 
if I can get a schematic i would do the upgrades myself.
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.
 
I totally agree with you concerning ultralinear. I would A/B the two settings when I had a set of Primaluna HP monoblocks with both kt88 and kt150 tubes. I will get the mb300. I have read that review and a few others. Thanks for your input. Much appreciated and I'll keep you posted
 

Latest posts

Back
Top