This is my first post here in the forum so I would like to say "Hello" to everyone. I've arrived here because I offered to take on a project for a friend and build a tube amplifier for him to use in his stereo system, so I'm looking for some advice and guidance...
First some background, I have plenty of experience repairing electronics, and have built a few tube guitar amplifiers in the years past, so no need to go over the basics. Plenty of experience repairing CRT monitors has taught me to respect electricity and how to work on it safely. Building high gain tube guitar amps has taught me a few of the finer points, like star grounding, biasing circuit schemes, different methods to power heaters etc. However, I have never built a tube amp for Hi Fidelity audio reproduction, my work with guitar amps was quite the opposite in fact...
So let me lay out what I am trying to achieve here and I hope some of you can offer me some advice and perhaps point me in the right direction.
My friend is into high end audio, or at least to the extent he can afford. He has some nice stuff, Threshold, Hafler, McIntosh, Carver etc, kind of a bit old school but nice quality. Lately he's been eying high end tube amps but they are way out of his price range, so he called me asking about these cheap Chinese tube amps on Ebay. Quick research told me they are a crap shoot at best and I advised him to stay away, at which point I offered to try and build him something if I can find a good design that we can afford to build.
He has a component system with an active crossover, the low end is covered by a 15" JBL Pro bottom end cabinet driven by a big SS amp, he would like to build a tube amp to cover the top end. He's running a pair of Bose 901's on the top end, so he doesn't need a ton of power, 35-50 WPC would be good I'm guessing. When he moved to Hawaii he had to sacrifice some of the larger/heavier audio equipment, electricity in Hawaii is also very expensive, so I was thinking a more efficient Push-Pull design would be better for him than a Class A design. It doesn't matter much to me if we go with a stereo design or two mono-block amps.
With that in mind, I'm wondering if anyone has a suggestion for something I could build that would suit his needs? I think perhaps a P-P pair of EL34's or KT88's on each channel would do? I would want to use solid state power supply, I don't see a need to bother with a rectifier tube on a hi-fi amp? The amp will not be reproducing bass at all, so were looking for sweet balanced mids and highs with ultra low distortion and noise levels.
As long as I can source the iron I can work from just a schematic and fabricate the rest from there, but I wouldn't be opposed to following a completed and tested design, or even building a kit. I just want it to be nice quality. If anyone would be so kind as to suggest what they might do, or point me in the direction where I might find something that works for me I would appreciate it...
Sorry for being long winded...
First some background, I have plenty of experience repairing electronics, and have built a few tube guitar amplifiers in the years past, so no need to go over the basics. Plenty of experience repairing CRT monitors has taught me to respect electricity and how to work on it safely. Building high gain tube guitar amps has taught me a few of the finer points, like star grounding, biasing circuit schemes, different methods to power heaters etc. However, I have never built a tube amp for Hi Fidelity audio reproduction, my work with guitar amps was quite the opposite in fact...
So let me lay out what I am trying to achieve here and I hope some of you can offer me some advice and perhaps point me in the right direction.
My friend is into high end audio, or at least to the extent he can afford. He has some nice stuff, Threshold, Hafler, McIntosh, Carver etc, kind of a bit old school but nice quality. Lately he's been eying high end tube amps but they are way out of his price range, so he called me asking about these cheap Chinese tube amps on Ebay. Quick research told me they are a crap shoot at best and I advised him to stay away, at which point I offered to try and build him something if I can find a good design that we can afford to build.
He has a component system with an active crossover, the low end is covered by a 15" JBL Pro bottom end cabinet driven by a big SS amp, he would like to build a tube amp to cover the top end. He's running a pair of Bose 901's on the top end, so he doesn't need a ton of power, 35-50 WPC would be good I'm guessing. When he moved to Hawaii he had to sacrifice some of the larger/heavier audio equipment, electricity in Hawaii is also very expensive, so I was thinking a more efficient Push-Pull design would be better for him than a Class A design. It doesn't matter much to me if we go with a stereo design or two mono-block amps.
With that in mind, I'm wondering if anyone has a suggestion for something I could build that would suit his needs? I think perhaps a P-P pair of EL34's or KT88's on each channel would do? I would want to use solid state power supply, I don't see a need to bother with a rectifier tube on a hi-fi amp? The amp will not be reproducing bass at all, so were looking for sweet balanced mids and highs with ultra low distortion and noise levels.
As long as I can source the iron I can work from just a schematic and fabricate the rest from there, but I wouldn't be opposed to following a completed and tested design, or even building a kit. I just want it to be nice quality. If anyone would be so kind as to suggest what they might do, or point me in the direction where I might find something that works for me I would appreciate it...
Sorry for being long winded...
+1
Plus there are some others that come to mind...
Peter Millett has a few boards out there, the "red" board has been discussed here quite a bit and he has a single ended board too.
There are some boards available at Shannon Parks site with the ST35 being a good starting point as well as some SE boards.
Another good resource just for research and inspiration is Tom McNally's Amps
Remember, tube "power output" is not apples to apples with modern solid state or chip gear. My Tubelab SSE only puts out like 7 or 8 watts but it makes plenty of music.
John Broskie's blog has a lot of data as well and I have built 2 power amps inspired by what I saw there. A PPEL34 which I did a DIY PCB for and a PPEL84 which I wired P2P.
I really like Edcor iron but you must understand that there is a typical 5 week leadtime.
Plus there are some others that come to mind...
Peter Millett has a few boards out there, the "red" board has been discussed here quite a bit and he has a single ended board too.
There are some boards available at Shannon Parks site with the ST35 being a good starting point as well as some SE boards.
Another good resource just for research and inspiration is Tom McNally's Amps
Remember, tube "power output" is not apples to apples with modern solid state or chip gear. My Tubelab SSE only puts out like 7 or 8 watts but it makes plenty of music.
John Broskie's blog has a lot of data as well and I have built 2 power amps inspired by what I saw there. A PPEL34 which I did a DIY PCB for and a PPEL84 which I wired P2P.
I really like Edcor iron but you must understand that there is a typical 5 week leadtime.
Thanks a bunch for the feedback. I just got done looking through the Tom McNally amp page, lotta amps there, plenty of food for thought...
It seems he is mainly into SE amps, which have a power range from a couple watts up to about 7W, which is a bit light on power IMHO even considering how much more sound per watt you get from tubes. To keep things in perspective, he has a 15" JBL pro sub in a folded horn driven by a Hafler XL-600 which puts out 900W when bridged to mono. I know tube watts put out more sound but paired with that 900W sub, it's gonna need some power! LOL
Ironically, the amps I was most interested on Tom's page were the P-P kits from Triode that he built (the rest seemed to be all SE lower wattage amps), I have purchased quite a bit of stuff from Triode in the past when I was building guitar amps, so I guess I should familiarize myself with my old friends over there...
That said, I had been thinking about more of a P2P design using some terminal strips or perhaps a small board with eyelets or turrets rather than an actual circuit board. A P-P EL34 design seems to be what it may be boiling down to...
I'm going to try and search out John Broskie's blog and other builders that were reference but not directly linked above and see what kinda builds they got out there.... Still open for suggestions...
Thanks again for your input, I appreciate it very much.
Last edited:
Its going to have to be PP to get the power you want here. Look at Allen Wrights Vacuum state PP1C for inspiration. This can be achieved on a modest budget if you don't go with the 300B version and will better almost any SE amp out there. Its mostly class A triode which in PP is a wonderful combination.
Start here http://www.diyaudio.com/forums/tubes-valves/180273-rundmaus-work-pp1c-without-sand.html
Shoog
Start here http://www.diyaudio.com/forums/tubes-valves/180273-rundmaus-work-pp1c-without-sand.html
Shoog
Last edited:
Thanks, looking that one up now...
One question though... You said it's Class A AND PP, which I was under the impression were pretty much mutually exclusive? Maybe I am confused about the classifications. For Class A I was assuming that all tubes must amplify the complete audio signal (both positive and negative side of the wave), and a Class A amp is also drawing full current always, even when the sound output is low or mute. Are these bad assumptions?
Since this amp will reside in Hawaii, where it is hot and the weather is generally tough on electronics, and electricity is very expensive... I was thinking I should stay away from Class A because of its constant current consumption, which will cost a lot for electricity and also make the amp run hot all the time and therefore more likely to fail sooner. I figured a Push Pull amp would give more power output with less current draw at idle and would therefore run cheaper and cooler than a Class A amplifier? Then you said "Class A Push Pull" and got me all confused! LOL
If I am way off base here please correct me, its been a few years since I dug into tube amp design and operation theory...
Hi, as suggested by others I think a good place to start would be millet's red board
DCPP Amp
I built one an it sounds terrific. Very balanced, detailed, plenty of power and since you know your way around a circuit you will be pleased to know Tubelab and others have modded the the h*** out of the board to produce in the excess of 125w of power.
The red board is very nice as basically every component is on the board itself (aside from transformers) so basically impervious to PTP induced hum etc.
Hope it helps.
DCPP Amp
I built one an it sounds terrific. Very balanced, detailed, plenty of power and since you know your way around a circuit you will be pleased to know Tubelab and others have modded the the h*** out of the board to produce in the excess of 125w of power.
The red board is very nice as basically every component is on the board itself (aside from transformers) so basically impervious to PTP induced hum etc.
Hope it helps.
Well, I kinda skimmed over that one for two reasons.
First I was kinda thinking big bottle tubes in sockets that are soldered to printed circuit boards and run in the tropics is not the best idea? Seems that board is gonna get hot, and the tube sockets etc might need soldering touch up after running a while and changing out tubes... He's going through problems right now similar to this with other equipment. Unfortunately I will not be there in Hawaii to help him maintain and/or repair this amp
, I was thinking an old school P2P layout would probably be more reliable for him?Second, I didn't like the fact that it was designed to run "cheap TV tubes".
That said, after doing some reading I gather the red board only has the smaller input tube sockets mounted on board, and it can run a variety of power tubes, so my issues are pretty much non issues.... I guess I should take another look at the red board and reconsider going that route. However, I still kinda wonder if a pcb should be needed to build a mid sized mono-block amplifier?
What's the budget? Do you have any particular output transformers in mind? Do you want global feedback or a no-feedback design?
I'd consider trioded KT88's; they'll do about 30W. In UL, they are good for a lot more than that.
Here are a few KT88 PP and a 6L6 PP design:
http://www.diyaudio.com/forums/tubes-valves/156699-mullard-5-20-kt88-pp-blocks.html
http://www.diyaudio.com/forums/tubes-valves/161702-opus-5-0-modern-mullard.html
http://www.diyaudio.com/forums/tubes-valves/133034-6l6gc-ab2-amp.html
Do a google search for Triode Dick's Mono Bill (or regular Bill) as well.... http://translate.google.com/translate?hl=en&sl=nl&u=http://www.triodedick.com/&prev=/search%3Fq%3Dtriode%2Bdick%26hl%3Den%26client%3Dfirefox-a%26hs%3DMhL%26rls%3Dorg.mozilla:en-US
fficial%26prmd%3Dimvnsfd&sa=X&ei=BdH4T5PcIKaC2wW9pNXEBg&ved=0CFcQ7gEwAA
The Opus and ChrisH's amp both use mosfet followers (aka Tubelab's "Powerdrive") The Tubemack amp is an updated Mullard 5-20 circuit and the Opus is the 5-20 with mosfet followers. IIRC, these all use CCS in the tails of the LTPs. I would use SS rectification with any of these designs. Chrish's amp was developed with lots of input from Tubelab George and uses two stages of LTPs for very low noise.
If the budget allows, consider James, Hashimoto, Tango, Electraprint, etc OT's. The Edcor offerings are a great value if the budget is too tight for the above.
I'd consider trioded KT88's; they'll do about 30W. In UL, they are good for a lot more than that.
Here are a few KT88 PP and a 6L6 PP design:
http://www.diyaudio.com/forums/tubes-valves/156699-mullard-5-20-kt88-pp-blocks.html
http://www.diyaudio.com/forums/tubes-valves/161702-opus-5-0-modern-mullard.html
http://www.diyaudio.com/forums/tubes-valves/133034-6l6gc-ab2-amp.html
Do a google search for Triode Dick's Mono Bill (or regular Bill) as well.... http://translate.google.com/translate?hl=en&sl=nl&u=http://www.triodedick.com/&prev=/search%3Fq%3Dtriode%2Bdick%26hl%3Den%26client%3Dfirefox-a%26hs%3DMhL%26rls%3Dorg.mozilla:en-US
fficial%26prmd%3Dimvnsfd&sa=X&ei=BdH4T5PcIKaC2wW9pNXEBg&ved=0CFcQ7gEwAAThe Opus and ChrisH's amp both use mosfet followers (aka Tubelab's "Powerdrive") The Tubemack amp is an updated Mullard 5-20 circuit and the Opus is the 5-20 with mosfet followers. IIRC, these all use CCS in the tails of the LTPs. I would use SS rectification with any of these designs. Chrish's amp was developed with lots of input from Tubelab George and uses two stages of LTPs for very low noise.
If the budget allows, consider James, Hashimoto, Tango, Electraprint, etc OT's. The Edcor offerings are a great value if the budget is too tight for the above.
Last edited:
Pete Millet actually has now about 3 different red boards for PP amps.
First was the transformer input one with the latest version on a red circuit board.
The second was the TV tube one with all tubes on it called the "Engineer's Amp"
The latest are mono driver boards with the output tubes outboard & you have to supply your own PS.
You can also pick a favorite out of the many Dynaco driver boards out there for 35-60 W/CH . Many of the aftermarket ST-70 ones will even drive KT-88 to KT-120's
Also look at Mark III & IV boards too.
Many of the LTP or Mullard style of Dynaco circuit boards out there now have CCS on the tail if you want that.
If you don't want any SS except the PS Diodes it looks like Triode's Boards still are all non SS
assistance.
If you don't want any SS and prefer P2P or even terminal boards, Eico's HF-50/60 look like a well liked design. There is even a mod by Dave Gillespie discussed on AK(Audiokarma) and on the Eico tube Form to change the input tube from EF86 to a 6CG7. Shannon Parks even has Mono boards for the same circuit Eico HF-87/89 which used different tubes. He calls them Eiclones. They have everything on the boards for easy foolproof wiring. I just thought I should mention the boards as they are a well liked design.
Another amp that used the Mullard was the Harman Kardon Citation V , and there are mods mentioned on the forms to sub the no longer in production 12BY7A.
Hope that helps!
Randy
First was the transformer input one with the latest version on a red circuit board.
The second was the TV tube one with all tubes on it called the "Engineer's Amp"
The latest are mono driver boards with the output tubes outboard & you have to supply your own PS.
You can also pick a favorite out of the many Dynaco driver boards out there for 35-60 W/CH . Many of the aftermarket ST-70 ones will even drive KT-88 to KT-120's
Also look at Mark III & IV boards too.
Many of the LTP or Mullard style of Dynaco circuit boards out there now have CCS on the tail if you want that.
If you don't want any SS except the PS Diodes it looks like Triode's Boards still are all non SS
assistance.
If you don't want any SS and prefer P2P or even terminal boards, Eico's HF-50/60 look like a well liked design. There is even a mod by Dave Gillespie discussed on AK(Audiokarma) and on the Eico tube Form to change the input tube from EF86 to a 6CG7. Shannon Parks even has Mono boards for the same circuit Eico HF-87/89 which used different tubes. He calls them Eiclones. They have everything on the boards for easy foolproof wiring. I just thought I should mention the boards as they are a well liked design.
Another amp that used the Mullard was the Harman Kardon Citation V , and there are mods mentioned on the forms to sub the no longer in production 12BY7A.
Hope that helps!
Randy
Last edited:
The Hammond 1650R & RA is also like by some for this type of application & the late Allen Wright liked the Lundahl C core output transformers using the LL1663 in his last PP amp.
Transcendar & Onetrics are two other West Coast manufacturers of OPT's mentioned by the diyer's as also liked on the forms too.
Randy
Transcendar & Onetrics are two other West Coast manufacturers of OPT's mentioned by the diyer's as also liked on the forms too.
Randy
Thanks a bunch for all the suggestions guys... I had been looking around at the various designs and the Dynaco ST-70 and ST-120 kinda jumped out at me. I'm gonna run those by my friend and see what he has to say, he's already a Hafler fan, having an XL-600. so he just might be into building one of those.
I wonder if the smaller one would be good to drive a set of Bose 901's, specially since he has a massive sub setup on the side already? 35 tube WPC seems pretty good to me for driving mids and highs through efficient 901's, 70 WPC seems might be even a bit excessive? What do you think?
I wonder if the smaller one would be good to drive a set of Bose 901's, specially since he has a massive sub setup on the side already? 35 tube WPC seems pretty good to me for driving mids and highs through efficient 901's, 70 WPC seems might be even a bit excessive? What do you think?
I've read they're (Bose 901) are power hungry, in fact the maker of the kit ST-120 amp recently, now makes a mono block with 125W/CH using 4 output tubes per channel. Called the M-125.
tubes4hifi amplifier KITs page
This may even more appropriate for those speakers as they need power to sound good!
If you ask, as somebody did I believe on his Form bought just the Output Transformers from him if you want to build to your own design. You can also take out 2 output tubes per channel and run it that way if you wish when you don't need the power.
As you may know to run 4 output tubes/CH you need a transformer with half the primary impedance & more importantly the power handling ability.
Hammond also makes a suitable transformer, and I see Transcendar has 200W rated one on their web site that they custom build to whatever primary impedance you want. A higher primary than std. can give you lower distortion and other better benefits at the cost of a bit of loss of power.
The Heathkit W-5M amp benefited in the sonics dept. greatly as it had 9K & higher primary output transformers.
As you may know the original Dynaco ST-120 was SS. You can't really call any of these clones of Dynacos any more except in looks, because of the totally different Mullard circuits used by most.
Randy
tubes4hifi amplifier KITs page
This may even more appropriate for those speakers as they need power to sound good!
If you ask, as somebody did I believe on his Form bought just the Output Transformers from him if you want to build to your own design. You can also take out 2 output tubes per channel and run it that way if you wish when you don't need the power.
As you may know to run 4 output tubes/CH you need a transformer with half the primary impedance & more importantly the power handling ability.
Hammond also makes a suitable transformer, and I see Transcendar has 200W rated one on their web site that they custom build to whatever primary impedance you want. A higher primary than std. can give you lower distortion and other better benefits at the cost of a bit of loss of power.
The Heathkit W-5M amp benefited in the sonics dept. greatly as it had 9K & higher primary output transformers.
As you may know the original Dynaco ST-120 was SS. You can't really call any of these clones of Dynacos any more except in looks, because of the totally different Mullard circuits used by most.
Randy
Last edited:
The design concept behing the Dynaco VTA ST-70 and VTA ST-120 was to make the amps LOOK LIKE an original Dynaco amp, yet be updated with a larger power transformer, triode/ultralinear switches, better driver circuitry etc. so that the amps would SOUND LIKE a modern tube amp. Both amps are VTA's VERSIONS of the older Dynaco amps.
True - There never was an original TUBE "Dynaco ST-120". The original Dynaco Stereo 120 was a solid state amp. Why not call the VTA ST-120 amp then an ST-125, ST-130, ST-135 etc? To do so, would go against the conservative power rating system found on all VTA amps. The VTA ST-70 is actually a 45 WPC amp (VTA ST-70 test) and the VTA ST-120 is really a 65 - 70 WPC amp.
The VTA M-125 monoblocks are not like any original Dynaco tube amp although Dynaco did have Mark VI monoblocks rated at 120 watts per monoblock. Unlike the VTA ST-70 and ST-120, the M-125 monoblocks have IEC AC connectors, a front power switch and rear RCA inputs like a modern tube power amp.
Bob Latino
True - There never was an original TUBE "Dynaco ST-120". The original Dynaco Stereo 120 was a solid state amp. Why not call the VTA ST-120 amp then an ST-125, ST-130, ST-135 etc? To do so, would go against the conservative power rating system found on all VTA amps. The VTA ST-70 is actually a 45 WPC amp (VTA ST-70 test) and the VTA ST-120 is really a 65 - 70 WPC amp.
The VTA M-125 monoblocks are not like any original Dynaco tube amp although Dynaco did have Mark VI monoblocks rated at 120 watts per monoblock. Unlike the VTA ST-70 and ST-120, the M-125 monoblocks have IEC AC connectors, a front power switch and rear RCA inputs like a modern tube power amp.
Bob Latino
Hmm, OK, I read the wiki about Dynaco and it said they followed up the ST-70 with the ST-120 but it wasn't as popular due to component failures. I assumed it was also a tube amp because I read somewhere else one of the major flaws in the ST-120 was the rail voltage was set higher than the voltage rating on the capacitors, which set the amp on a coarse toward failure as soon as she powered up... I had assumed the redesigned ST-120 had beefed up the cap voltage and other parts that were common points of failure, but from what you are telling me the ST-120 never originally existed as a tube amp I guess?
Back to the Bose 901's... I have completely the opposite impression about the 901's, they seem to be extremely efficient speakers to me? Compared to my Dahlquist DQ-10's they're easy to drive, but I think in general they are an efficient main speaker because they have no large woofer, I don't even think they have any passive crossover components in them,they only have the 9 smaller speakers in them? (It seems with 9 identical full range drivers inside they probably don't even have any passive crossover components in them to soak power?) If anyone else has experience with Bose 901's and would like to weigh in their opinion on how efficient they are, and how much tube power I need to drive them (with the bass stripped out by an electronic crossover and sent to the sub)?
At any rate, the ST-70 is climbing toward the top of my list, and I may consider the ST-120 if we decide that we do need the extra power, but I am still open for suggestions....
Thanks again for all your feedback...
PS I realize these are not "Dynaco" amps, as they were done long ago, and David Hafler went on to design SS amps and start up the Hafler company etc etc. I do believe the original Dynaco amps were offered in built or kit form, much like the early Hafler amps such as the DH-500?
Back to the Bose 901's... I have completely the opposite impression about the 901's, they seem to be extremely efficient speakers to me? Compared to my Dahlquist DQ-10's they're easy to drive, but I think in general they are an efficient main speaker because they have no large woofer, I don't even think they have any passive crossover components in them,they only have the 9 smaller speakers in them? (It seems with 9 identical full range drivers inside they probably don't even have any passive crossover components in them to soak power?) If anyone else has experience with Bose 901's and would like to weigh in their opinion on how efficient they are, and how much tube power I need to drive them (with the bass stripped out by an electronic crossover and sent to the sub)?
At any rate, the ST-70 is climbing toward the top of my list, and I may consider the ST-120 if we decide that we do need the extra power, but I am still open for suggestions....
Thanks again for all your feedback...
PS I realize these are not "Dynaco" amps, as they were done long ago, and David Hafler went on to design SS amps and start up the Hafler company etc etc. I do believe the original Dynaco amps were offered in built or kit form, much like the early Hafler amps such as the DH-500?
Last edited:
More power is an issue when:
1) power consumption related costs weigh on the design
2) reliability is compromised
3) durability is dimished
4) listening space cannot tollerate the heat (and right now I have 750w of filaments running 1m from my laptop. Not very entertaining in this time of year with the air con not functioning properly)
I would like to advise you to trace an idle power consumption line based on tube type, topology, filament power. At least you'll now the minimum amount of both energy and heat coming from the amp. With that in mind choose the design you feel is more appropriate for your friend's needs
P.s. don't underestimate heat from a stereo set and an inefficient (albeit HIFI) topology. Heat and the cost of electricity will soon take their toll and the user may be less and less inclined to switch the amp on.
1) power consumption related costs weigh on the design
2) reliability is compromised
3) durability is dimished
4) listening space cannot tollerate the heat (and right now I have 750w of filaments running 1m from my laptop. Not very entertaining in this time of year with the air con not functioning properly)
I would like to advise you to trace an idle power consumption line based on tube type, topology, filament power. At least you'll now the minimum amount of both energy and heat coming from the amp. With that in mind choose the design you feel is more appropriate for your friend's needs
P.s. don't underestimate heat from a stereo set and an inefficient (albeit HIFI) topology. Heat and the cost of electricity will soon take their toll and the user may be less and less inclined to switch the amp on.
More power is an issue when:
1) power consumption related costs weigh on the design
2) reliability is compromised
3) durability is dimished
4) listening space cannot tollerate the heat (and right now I have 750w of filaments running 1m from my laptop. Not very entertaining in this time of year with the air con not functioning properly)
I would like to advise you to trace an idle power consumption line based on tube type, topology, filament power. At least you'll now the minimum amount of both energy and heat coming from the amp. With that in mind choose the design you feel is more appropriate for your friend's needs
P.s. don't underestimate heat from a stereo set and an inefficient (albeit HIFI) topology. Heat and the cost of electricity will soon take their toll and the user may be less and less inclined to switch the amp on.
You are right on target man, exactly the same stuff I told him when he called me asking about tube amps. He has a boatload of audio equipment, at least 2 spare SS amps along side the SS stuff he is driving his speakers with now. When I mentioned the tubes will draw lots more power and make lots of heat he said "I wont use it all the time, I'll hook it up when I want to listen to it, and leave the SS amp in place for day to day use". So he is already aware of that.
My advice to him was to save up a few bucks and buy an old school SS McIntosh power amp instead. Before we shipped all his audio equipment to Hawaii we had an amplifier throwdown. After listening to his Hafler XL-600, his Threshold Stasis (can't remember if it's a 2 or 3), his Dennon amp, and an Ashley, Peavy and Sound Craftsman just for grins he had to admit that my McIntosh MC-2205 sounded the best out of all of them. It was the only amp in the bunch that utilized output transformers (even though it is a SS amp). So logic dictates if that amp pleased his ear the most he should seek out something along that line. Unfortunately he's not as logical of an individual as me, he follows his gut more and his gut is telling him (right now) he needs to listen to tubes! LOL So I just try to offer him the best advice I can and help him out in whatever direction he seems to be going. In the end I think it's gonna require a trip to Hawaii to work it out....
I really appreciate you guys taking the time to pass on all this good advice, thank you very much...
Talked to my Friend about the tube amp project today. I pointed him toward the Dynaco clones to have him check them out, he pointed me toward an amp he found made by some guy in Greece. (you guessed it, my friend is Greek and proud! LOL)
The amps we both came up with were pretty similar actually, the Greek amp might even be a Dynaco clone, I haven't had a chance to dig in and compare yet. The guy designed a second amp that has 4 EL34's per channel that can push 70W, which seems like a more reasonable proposition than trying to squeeze 70W out of a pair of KT88's?
Here are the links to those amps, kinda limited info, but maybe someone here knows more and would chime in on the subject? (unfortunately the guys website is in Greek! The first two links are in english...)
EL34 audio power amp | Tube Amps DIY
EL34 push pull DIY project | Tube Amps DIY
????????? TV - ????????????? Hi Fi ???????? ????????? - ??????? ???????????
PS all the ????? are because of the greek text I guess....
The amps we both came up with were pretty similar actually, the Greek amp might even be a Dynaco clone, I haven't had a chance to dig in and compare yet. The guy designed a second amp that has 4 EL34's per channel that can push 70W, which seems like a more reasonable proposition than trying to squeeze 70W out of a pair of KT88's?
Here are the links to those amps, kinda limited info, but maybe someone here knows more and would chime in on the subject? (unfortunately the guys website is in Greek! The first two links are in english...)
EL34 audio power amp | Tube Amps DIY
EL34 push pull DIY project | Tube Amps DIY
????????? TV - ????????????? Hi Fi ???????? ????????? - ??????? ???????????
PS all the ????? are because of the greek text I guess....
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.