So I am embarking on my next project (won't actually start construction for a little while) and have decided on Poinz' Musical Machine.
I've got most of the basic parts but have a quick question before I finish buying everything. I've read lots of talk about two different tubes in the driver slot, a 5965 or a 6GK5. I've got both, but have no idea why I should go with one over the other.
More questions to come, but that's a start.
I've got most of the basic parts but have a quick question before I finish buying everything. I've read lots of talk about two different tubes in the driver slot, a 5965 or a 6GK5. I've got both, but have no idea why I should go with one over the other.
More questions to come, but that's a start.
The 6GK5 is much superior. 60% more gain, 15% lower Zout, more linear, and the predicament of finding a computer tube with 5% or better balance between the two devices in the bottle is neatly sidestepped.
Except for a couple pairs for my own clients, I gave my 5965s away.
Aloha,
Poinz
AudioTropic
Except for a couple pairs for my own clients, I gave my 5965s away.
Aloha,
Poinz
AudioTropic
Good choice, bigjppop.
You can't go wrong with a 6v6 PP triode amp. No 2a3 amp SE for me, I've tried those.
I started it with the Musical Machine, but nowadays I'm using a floating paraphase splitter stolen from a Leben integrated PP amp.
I agree with Poindexter, the 5965 triodes are rarely matched, but it is a good sounding tube. The LTP splitter needs another tube I guess, Poinz changed the tube, I kept the tube and changed the phase splitter.
Power supply and the output stage remain the same.
You can't go wrong with a 6v6 PP triode amp. No 2a3 amp SE for me, I've tried those.
I started it with the Musical Machine, but nowadays I'm using a floating paraphase splitter stolen from a Leben integrated PP amp.
I agree with Poindexter, the 5965 triodes are rarely matched, but it is a good sounding tube. The LTP splitter needs another tube I guess, Poinz changed the tube, I kept the tube and changed the phase splitter.
Power supply and the output stage remain the same.
Well I guess straight from the horse's mouth is about as good of an endorsement as you can get. Is there an updated schematic/parts list for the 6GK5 version?
Thanks for the schematic.
I'm not really sure what can be done "differently." I haven't seen much conversation around here of mods for this amp; it seems most are pretty happy with it just the way it is. I'll using the recommended Silk OPT's and (now) the 6GK5 tubes. Probably no input selector (I only use one source) and a somewhat decent volume pot (probably not the $200 flavor).
I'm definitely open to suggestions/ideas but it seems Poinz has worked this thing over pretty well over several years/iterations.
I'm not really sure what can be done "differently." I haven't seen much conversation around here of mods for this amp; it seems most are pretty happy with it just the way it is. I'll using the recommended Silk OPT's and (now) the 6GK5 tubes. Probably no input selector (I only use one source) and a somewhat decent volume pot (probably not the $200 flavor).
I'm definitely open to suggestions/ideas but it seems Poinz has worked this thing over pretty well over several years/iterations.
You are absolutely correct. I think that is about a perfect operating plan as you'll find.
That amp has fifteen years of development behind it, guys. The chance of improving it with a random mod is pretty small. I've tried bloody everything.
The outpput transformers and coupling caps are critical parts. Use 10K outputs, and not cheapo stuff. 8K sound a little creamy, tubey. Best caps I've tried are the Rel RT styrene/tin from Michael Percy, and they're reasonable in price, too. Big heavy buggers, though.
The driver plate load resistors and volume pot are important, too. I've been using Kiwames, but there may be other good stuff. Have plenty of rating there, you don't want heat induced distortion in that element. I use 2 2W in parallel. The volume pots, I tell you, any of the good ones sound almost the same to me. Alps black or blue, TKD, DACT all work fine. I use the DACT because my market presentation is hoity toit, and it takes John Chapman's outstanding remote volume (remote volume is very popular, and for good reason).
Rest of the resistors are nice quiet 1% BC metal films with plenty of rating, the power supply caps are Panasonic TSHA, TSHB, TSED, unbypassed. I find these superior to the old Cerafines, indistinguishable from Black Gates.
Pad the heater line down a little below rating (6.2V) with fractional-ohm Ohmite wirewounds, and put a 10μF NP Muse across this line on the transformer side of these to keep the HF rubbish out of the heaters. My tubes last 30 - 40,000 hours because of this. Don't let your heaters stay at 6.5V.
Aloha,
Poinz
AudioTropic
The outpput transformers and coupling caps are critical parts. Use 10K outputs, and not cheapo stuff. 8K sound a little creamy, tubey. Best caps I've tried are the Rel RT styrene/tin from Michael Percy, and they're reasonable in price, too. Big heavy buggers, though.
The driver plate load resistors and volume pot are important, too. I've been using Kiwames, but there may be other good stuff. Have plenty of rating there, you don't want heat induced distortion in that element. I use 2 2W in parallel. The volume pots, I tell you, any of the good ones sound almost the same to me. Alps black or blue, TKD, DACT all work fine. I use the DACT because my market presentation is hoity toit, and it takes John Chapman's outstanding remote volume (remote volume is very popular, and for good reason).
Rest of the resistors are nice quiet 1% BC metal films with plenty of rating, the power supply caps are Panasonic TSHA, TSHB, TSED, unbypassed. I find these superior to the old Cerafines, indistinguishable from Black Gates.
Pad the heater line down a little below rating (6.2V) with fractional-ohm Ohmite wirewounds, and put a 10μF NP Muse across this line on the transformer side of these to keep the HF rubbish out of the heaters. My tubes last 30 - 40,000 hours because of this. Don't let your heaters stay at 6.5V.
Aloha,
Poinz
AudioTropic
Poinz:
Thanks for the detailed spec rec's; I'm after good quality stuff, without breaking the bank (aren't we all!).
Question on the PS caps, I'm curious as to the suitability of one of those giant 600 uf/500V polypropylene caps. I've got the room in my chassis and when it comes right down to it... doesn't everyone want at least one giant cap in their amp somewhere
Thanks for the detailed spec rec's; I'm after good quality stuff, without breaking the bank (aren't we all!).
Question on the PS caps, I'm curious as to the suitability of one of those giant 600 uf/500V polypropylene caps. I've got the room in my chassis and when it comes right down to it... doesn't everyone want at least one giant cap in their amp somewhere
600μF is way too much capacitance for this circuit. I use whatever it takes to hit my DC voltage target before the choke, a bigazz choke, 120μF in the 'power' position, and 56μF in the driver supply. Use of huge value capacitors even if they're nice will slow down the amp. All capacitors have some sound, some deviation from perfect, and this deviation increases as the value. I use 450V TSHB in the first and second positions, 400V TSHA in the third. If you have some of those nice film caps in values more like this, I'm sure they'll sound great. The third, driver cap is the most critical.
Aloha
Poinz
AudioTropic
Aloha
Poinz
AudioTropic
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What about Solen poly caps? (same size as specced)
You mean value and rating (microfarads and volts). I'm sure they'll work fine. I personally don't think they'll sound noticeably better, but certainly just as good.
Listening to Hilary and Rachel play the Bach two fiddles on the proto product amp right now. WooHoo!!
The 5AR4 doesn't have quite the 'pop' of the sand rectifiers, but the timbres are just delicious.
Aloha,
Poinz
AudioTropic
You mean value and rating (microfarads and volts). I'm sure they'll work fine. I personally don't think they'll sound noticeably better, but certainly just as good.
Listening to Hilary and Rachel play the Bach two fiddles on the proto product amp right now. WooHoo!!
The 5AR4 doesn't have quite the 'pop' of the sand rectifiers, but the timbres are just delicious.
Aloha,
Poinz
AudioTropic
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