Is single ended really worth it?
I'm getting ready to jump in that pool by building an 8-10 WPC single ended KT-88 integrated tube amp and still flummoxed at the idea of spending some not inconsiderable cash on Input transformers, output transformers, chokes, etc etc to get some unadulterated flea power.
Just tell me yes, so I won't think I'm chasing windmills. I've been a solid state guy for 30 years and a tube guy for 3 years so this is a big shift.
-Don Quixote
“Finally, from so little sleeping and so much reading, his brain dried up and he went completely out of his mind.”
― Miguel de Cervantes Saavedra, Don Quixote
I'm getting ready to jump in that pool by building an 8-10 WPC single ended KT-88 integrated tube amp and still flummoxed at the idea of spending some not inconsiderable cash on Input transformers, output transformers, chokes, etc etc to get some unadulterated flea power.
Just tell me yes, so I won't think I'm chasing windmills. I've been a solid state guy for 30 years and a tube guy for 3 years so this is a big shift.
-Don Quixote
“Finally, from so little sleeping and so much reading, his brain dried up and he went completely out of his mind.”
― Miguel de Cervantes Saavedra, Don Quixote
Personally I think not since I think a top flight PP amp designed with the same care and attention (and money) lavished on most SE amps will generally better any SE amp.
But thats just me.
Shoog
But thats just me.
Shoog
I love, love, love my 833C SET. The sound it produces from my relatively inefficient speakers is intoxicating to me. Clean, clear, warm, dimensional, transparent, I'm running out of adjectives...Does it measure perfectly? No, but the sound is what counts for me.
It sounds better to me than anything else I've heard. YMMV, of course. The system as whole and how it works together is what makes or breaks it, IMO.
It sounds better to me than anything else I've heard. YMMV, of course. The system as whole and how it works together is what makes or breaks it, IMO.
You could try and have it both ways. Do a KT-88 P-P class A amp and configure one side as triode or UL, and the other side as pentode. Make the grid drive to the pentode side switchable too, between P-P drive or AC ground for that side. With drive on both sides, you may get 2X SE power.
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Yeah, that is sorta what I am going to do, it will be triode then a switch will put it in pentode mode doubling the output from 8 watts to a whopping space warping 16 watts.
😛
I am trying to keep things an simple as humanly possible with as few parts as possible.
I guess we will see. 😀
Magz, did you try a smaller SET amp before your monster?
Based purely on the contents of your post, the responsible answer to your question is, "No, don't do it."
Nope, went straight for the gusto. I had heard smaller SETs on friends' systems, though, and liked them, which is why I was inspired to build mine - with the speakers I have, a flea-watter was not an option.
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GO FOR IT !
I've spend hundreds of hours simulating/designing, laying out pcbs, refining parts choices, building, debugging and testing SS amps. I've enjoyed every minute. My 'best' amp is a SS amp.
What am I listening to everyday ? - the very first SET amp I ever built. It's not expensive, simple 6AS7 single ended, 6SN7 driver, Hammond budget output transformer. It's not perfect by any means, but still sounds sooooooo good 😀
I've spend hundreds of hours simulating/designing, laying out pcbs, refining parts choices, building, debugging and testing SS amps. I've enjoyed every minute. My 'best' amp is a SS amp.
What am I listening to everyday ? - the very first SET amp I ever built. It's not expensive, simple 6AS7 single ended, 6SN7 driver, Hammond budget output transformer. It's not perfect by any means, but still sounds sooooooo good 😀
SE Worth it...?
I think this is one of those questions where if you ask 10 people, you could get 10 different answers.
My take on this... I am a slow builder. I collect way more bits for projects than I have time to complete. So I plan to build three valve amplifiers in my lifetime. If I build more, that's a bonus, but right now I have a push-pull, completed about 20 years ago. I am half way through my parallel single-ended, and and the end of the line there is my OTL circlotron monster. They are all worth it to me.
The reward is in the doing as much as in the end result. It keeps me happy, and that's what counts.
I think this is one of those questions where if you ask 10 people, you could get 10 different answers.
My take on this... I am a slow builder. I collect way more bits for projects than I have time to complete. So I plan to build three valve amplifiers in my lifetime. If I build more, that's a bonus, but right now I have a push-pull, completed about 20 years ago. I am half way through my parallel single-ended, and and the end of the line there is my OTL circlotron monster. They are all worth it to me.
The reward is in the doing as much as in the end result. It keeps me happy, and that's what counts.
Why input transformers?
Build a small SE and make it switchable triode UL possibly RH and play with the feedback..
I have built loud PPP amps loved them...but I could not understand what all the fuss was about SE..it makes no sense..until you build one.
BUT and its a big BUT..you have to try different feedback options and wait for the FLAMES components..however you don't have to spend a fortune.
The power ...hum... why don't I miss it????
Just remember the PSU is more important in SE..boy does it let hum through..so strangle the amp with regulation..er perhaps you are on the edge of something..
Oh dear you use speakers don't you..😀
You can make a SE that sounds like a SS amp or you can make one that sounds all warm like an old radio or you can make one that you can hear people breath..however YMMV.<<you are the cause not the SE..Oh its all warm ...wrong..oh its like a SS amp..wrong...😀
Remember to wait for the moon to be full and run your hand over the components and think whatever I use will not be in for long..😀
perhaps better leave it alone..stick to the safe side of the street.
Regards
M. Gregg
Build a small SE and make it switchable triode UL possibly RH and play with the feedback..
I have built loud PPP amps loved them...but I could not understand what all the fuss was about SE..it makes no sense..until you build one.
BUT and its a big BUT..you have to try different feedback options and wait for the FLAMES components..however you don't have to spend a fortune.
The power ...hum... why don't I miss it????
Just remember the PSU is more important in SE..boy does it let hum through..so strangle the amp with regulation..er perhaps you are on the edge of something..
Oh dear you use speakers don't you..😀
You can make a SE that sounds like a SS amp or you can make one that sounds all warm like an old radio or you can make one that you can hear people breath..however YMMV.<<you are the cause not the SE..Oh its all warm ...wrong..oh its like a SS amp..wrong...😀
Remember to wait for the moon to be full and run your hand over the components and think whatever I use will not be in for long..😀
perhaps better leave it alone..stick to the safe side of the street.
Regards
M. Gregg
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I think "intoxicating" sums it up perfectly. There is something that draws me to listen to my single ended amp.... almost every day..
Some days I want it loud, and blast my PPP amp in my basement, but usually it's the SET.
I have to say though.. There is really not that much difference between my no feedback set, and my high feedback parallel push pull amps.
Both have good components, attention to detail, weren't rushed, and were tested and adjusted.
Maybe single ended is easier to get right, too.. I've built a few and like them all.
I have a bunch of push pull amps I don't like at all.. (but as I said above, and others have said, PP can be very good, too).
it depends entirely on what you are trying to achieve and with what speakers.
Without further information a sensible answer is impossible.
Why one side triode/UL and the other side pentode?😕 I thought making both triode or UL, then just switch AC ground one side to get SE. Then you have DC current induced flux cancelled.
The pentode has a high Rp, like a CCS, so it will not load down the SE signal generated by the other side.
Driving the pentode as well would then give twice the output besides, although it will not be pure SE effects then.
So AC ground the pentode input (becoming a CCS) for real SE effects from the triode side, or drive the pentode too for a 1/2 SE effect with twice the power out.
(the driven pentode will still need its grid drive reduced from the ordinary matched P-P case, since the triode wired side will not have the same effective gm due to the triode Rp feedback. So one will need to measure avg DC on each side at maybe normal listening level, and adjust the pentode drive level. 2nd harmonic generation is causing the DC effects.)
Driving the pentode as well would then give twice the output besides, although it will not be pure SE effects then.
So AC ground the pentode input (becoming a CCS) for real SE effects from the triode side, or drive the pentode too for a 1/2 SE effect with twice the power out.
(the driven pentode will still need its grid drive reduced from the ordinary matched P-P case, since the triode wired side will not have the same effective gm due to the triode Rp feedback. So one will need to measure avg DC on each side at maybe normal listening level, and adjust the pentode drive level. 2nd harmonic generation is causing the DC effects.)
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How about keeping UL or triode on both side, use multiple pole switch to switch one side to pentode and AC ground the input for SE. Then you have balance UL/triode, but going to SE/ground pentode with a switch? That would be very interesting to try if it can work.
Well, you need to keep the DC balanced in all cases for the OT. (one is just AC grounding the pentode input, DC bias still there) One might still need a DC servo to auto -balance, since a plate/screen voltage shift will change the operating point. Depends on the DC level the screen gets switched to also.
Push-pull would seem the natural choice where balance can be attained. Freedom from some power supply concerns for example. Distortion reduction as well.
If a PP amp has imbalance it may interact with the supply the same as a single ended stage will. The single ended version will include its impression of the fundamental including stage distortion on the supply, whereas the push pull version will only impress the distortion, who's character may also be different than the single ended stage.
I think some single ended designers prefer to deal with the supply differently. Push pull also responds to a good and appropriate supply.
The no signal quiescent current is DC current. At no signal, an ultra linear draw the same current as pentode as the screen is at the same voltage as anode. So if you switch to pentode and ground the grid, you should get the same quiescent current. Right?
So don't do triode, just UL.
Also, from my understanding, OPT with air gap is more linear. Get one with air gap and it can stand imbalance current. From what I've read, Lundahl make transformers that can be used for PP and SE. get one of those and do the best to switch the tube.
I am quite interested in this, I don't want to commit to SE, but I am interested in at least trying.
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