Since "great sounding" is somewhat subjective, here's an oldie for your consideration. The output tranny is a Dynaco A450 and KT-88s could be substituted. There is an error omission in the power supply. There should be a connection from one 5U4 plate to the 6X4 cathode.
Attachments
The words, "great sounding" is kind of loaded... but check out Triode Guy's schematic. It has been in my bookmarks for the longest time, just never had the nerve to build something to this scale of complexity (I am still collecting parts for a KT88 SE amp as project one of three). How complex you ask? Well, not being the most knowledgeable of electrical types, the power source schematic made my jaw drop... the link to the PSU .pdf is on the webpage below.
KT88 PPP
Not sure if it sounds good as that is all subjective, but at 60 W a side with a stated bandwidth of 10 Hz to 50 kHz, there has to be some usable clean sound from it.
KT88 PPP
Not sure if it sounds good as that is all subjective, but at 60 W a side with a stated bandwidth of 10 Hz to 50 kHz, there has to be some usable clean sound from it.
Whoops, I just re-read your original post. I thought you were looking for a schematic of a 4 tube KT88 amp. If not, then if you are looking for a kit (not ready made), then you might want to check out Bob Latino's M125 monoblocks. They are rock solid from the stuff I have read on various forums and have a clean sound. The support that you get is second to none. I have emailed Mr. Latino and he was very approachable and answered all my questions regarding kit difficulty and "completedness" of the instructions.
tubes4hifi amplifier KITs page
Take this with a grain of salt as I might be biased since I an still considering getting the Latino ST-70 Dynaco amp (you will see on the same webpage) and running those with a low gain tube and 6550 or KT88 tubes. This is only if project one doesn't get off the ground....
tubes4hifi amplifier KITs page
Take this with a grain of salt as I might be biased since I an still considering getting the Latino ST-70 Dynaco amp (you will see on the same webpage) and running those with a low gain tube and 6550 or KT88 tubes. This is only if project one doesn't get off the ground....
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mr2racer (Kevin?)
An old thread, I think you may have seen it before.
http://www.diyaudio.com/forums/tubes-valves/54941-dynaco-120w-amp-dyna-451-a.html
Cheers,
Ian
An old thread, I think you may have seen it before.
http://www.diyaudio.com/forums/tubes-valves/54941-dynaco-120w-amp-dyna-451-a.html
Cheers,
Ian
Thanks All,
Maybe I should have been more specific when I started this thread. I was trying to find a design to rebuild my Dynaco Mark VI's. To go with an all triode front end would be wonderful but there isn't room in the chassis for all those octal sockets. And the A-451 amp in the Dynaco catalog would be easy but I'm not crazy about the pentode/triode 6An8 front end as I think the 7199 sounds better, from my research.
Kim recommended a 6414 or 12BH7 front end in a parallel setup. I'm assuming the parallel design is like the one HollowState posted above. It reminds me of some of the Audio Research schematics I've seen. The Music Angel uses a 12AX7/12AT7 front end in a long tail pair. This was SY's recommendation.
At this point I think the most logical thing to do is DESIGN a new front end. That would be new ground for me but it should be doable. Morgan Jones has a very complete explanation for designing an amplifier with a 12AX7. And Aiken Amps has a tutorial on building a phase splitter. So that's where I'll go next.
The purpose of this exercise is to get enough open loop gain that I can add enough feedback to make these amps sound good. I'll let you know how it comes out.
And, as always, thanks very much for your help! Kevin
Maybe I should have been more specific when I started this thread. I was trying to find a design to rebuild my Dynaco Mark VI's. To go with an all triode front end would be wonderful but there isn't room in the chassis for all those octal sockets. And the A-451 amp in the Dynaco catalog would be easy but I'm not crazy about the pentode/triode 6An8 front end as I think the 7199 sounds better, from my research.
Kim recommended a 6414 or 12BH7 front end in a parallel setup. I'm assuming the parallel design is like the one HollowState posted above. It reminds me of some of the Audio Research schematics I've seen. The Music Angel uses a 12AX7/12AT7 front end in a long tail pair. This was SY's recommendation.
At this point I think the most logical thing to do is DESIGN a new front end. That would be new ground for me but it should be doable. Morgan Jones has a very complete explanation for designing an amplifier with a 12AX7. And Aiken Amps has a tutorial on building a phase splitter. So that's where I'll go next.
The purpose of this exercise is to get enough open loop gain that I can add enough feedback to make these amps sound good. I'll let you know how it comes out.
And, as always, thanks very much for your help! Kevin
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There are a pair of Quicksilver 8417 mono block amps on ebay at the moment. They have a nice heavy transformers and with an hrs worth of work will sound very good with KT88's, 6550's, 6bg6ga's, and a few other tubes. As they come from the factory they are capable of running KT88's without paralleling up the VA and phase spitter tube sections like mentioned on the Triode page.
My current pair of them has individual output tube bias adjustment capabilities. They will outperform the Music Angels with ease.
My current pair of them has individual output tube bias adjustment capabilities. They will outperform the Music Angels with ease.
Yes, this is a nice example using symmetric input.... but IMHO, there are some errors within the amp input circuit using the (-) XLR connection and the SW 3 switch.
HpW
Not sure my opinion is worth anything, but, I am an owner of one of the Music Angel KT88 amps, the 808 model to be exact. Is it the best amp in the known world, I am sure it is far from it, is it the best 500ish dollar amp I have ever heard, it is actually, that includes solid state or tube. I havent even taken out the stock tubes that came with it yet, so that should make an even better sound. As far as the amp build, could be far better, but could be far worse, I highly doubt that this chasis could be built for the price of the whole amp, so if you want a decent amp that sounds good and is built failry well(weighs around 50 pounds), I couldnt tell you not to go ahead with a Music Angel, because I am actually enjoying mine. I will say that the 808 model is reputed to be basically a fixed version of the 800 model, which I guess had alot of issues, someone has even said that the 808 model was fixed using alot of the mods from the various forums. Crazy world we live in when factory's are using forum mods to build there amps, but hey if it makes them better Im all for it.
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