Hi,
Nah, never happened so far.
Honestly, I really wouldn't know how to even make that happen.
OTL amps are mainly just PP amps with a SEPP output stage.
Everything in front of that is just the same stuff you'd find in any amp.
Fuse B+/B- and nothing bad can happen.
My OTLs run twenty powertriodes in parallel.
Any big poweramp with that many tubes will need the occasional servicing, whether the nameplate says ARC, Carver Silver Seven, CJ or any OTL.
Unreliable? No, not when designed properly they're not.
No, I think I was saying or at least I've stated it here somewhere, that you can hardly build a real world OTL without applying NFB to reduce Zout to interface an ordinary speaker.
The EMF from the speaker is included in the NFB loop but at least you don't have to deal with the OPT in the equation anymore.
As with all NFB, use it judiciously and you'll be fine, use it as a bandaid to straighten things out and expect trouble in paradise.
If you value music reproduction in the home you owe it to yourself to listen at least once in your life to a well designed OTL amp.
It is an ear opener...........
Cheers, 😉
Nah, never happened so far.
Honestly, I really wouldn't know how to even make that happen.
OTL amps are mainly just PP amps with a SEPP output stage.
Everything in front of that is just the same stuff you'd find in any amp.
Fuse B+/B- and nothing bad can happen.
My OTLs run twenty powertriodes in parallel.
Any big poweramp with that many tubes will need the occasional servicing, whether the nameplate says ARC, Carver Silver Seven, CJ or any OTL.
Unreliable? No, not when designed properly they're not.
No, I think I was saying or at least I've stated it here somewhere, that you can hardly build a real world OTL without applying NFB to reduce Zout to interface an ordinary speaker.
The EMF from the speaker is included in the NFB loop but at least you don't have to deal with the OPT in the equation anymore.
As with all NFB, use it judiciously and you'll be fine, use it as a bandaid to straighten things out and expect trouble in paradise.
If you value music reproduction in the home you owe it to yourself to listen at least once in your life to a well designed OTL amp.
It is an ear opener...........
Cheers, 😉
quite a few OTLs have parasitic oscillation issues.
The famous Futterman did, as did the NYAL versions of that basic circuit.
The apparent reason for that appears to be that the tubes had nothing to "slow them down", being good out to VHF frequencies... and prone to capacitive coupled signals...
That doesn't mean that the newer ones aren't stable... or not.
_-_-bear
The famous Futterman did, as did the NYAL versions of that basic circuit.
The apparent reason for that appears to be that the tubes had nothing to "slow them down", being good out to VHF frequencies... and prone to capacitive coupled signals...
That doesn't mean that the newer ones aren't stable... or not.
_-_-bear
Re: Confusion reigns!
Triodes may be somewhat easier to make a nice amp with (since they're intrinsically more linear), but condemning ALL pentodes and beam tetrodes as being unworthy is too much of a generalisation. The "sound" of an amp has much to do with the circuit topology, not just the devices used within it.
Maybe. But some might still sound like rubbish.
bear said:
Triodes may be somewhat easier to make a nice amp with (since they're intrinsically more linear), but condemning ALL pentodes and beam tetrodes as being unworthy is too much of a generalisation. The "sound" of an amp has much to do with the circuit topology, not just the devices used within it.
bear said:
Maybe. But some might still sound like rubbish.
Bear
I would go down the path of building a less expensive 300B from scratch, and learn most that way if hwas youngrert and nore time. But my primary interest is speakers; in amps I value expediency over learning. (re cake pans, I built a gainclone in a biscuit tin).
I can get Chinese Frontier 300Bs here in Oz for AU$315/pair (=USD 246) – but I suspect it’s not that cheap.
Maybe if I hear a decent, inexpensive amp from China, I may get one, but I have a Chinese Opera Audio 2*EL34 Electro Harmonix integrated, it’s good in some things (eg treble), not in others (bass). Maybe down the track I’ll cannibalise it. I also have a mid 60s Technics totally tube AM/ FM receiver that could be full of goodies(??).
I’ve read three reports at AA that Transcendent Stereo OTLs give almost no problems. 😎
My priorities in sound for this amp are 1 immediacy/ transient response, 2 midrange, 3 treble. Based on what I’ve read to date (mostly at AA), that fits best with OTLs, especially point 1. Any alternative views?
I would go down the path of building a less expensive 300B from scratch, and learn most that way if hwas youngrert and nore time. But my primary interest is speakers; in amps I value expediency over learning. (re cake pans, I built a gainclone in a biscuit tin).
I can get Chinese Frontier 300Bs here in Oz for AU$315/pair (=USD 246) – but I suspect it’s not that cheap.
Maybe if I hear a decent, inexpensive amp from China, I may get one, but I have a Chinese Opera Audio 2*EL34 Electro Harmonix integrated, it’s good in some things (eg treble), not in others (bass). Maybe down the track I’ll cannibalise it. I also have a mid 60s Technics totally tube AM/ FM receiver that could be full of goodies(??).
I’ve read three reports at AA that Transcendent Stereo OTLs give almost no problems. 😎
My priorities in sound for this amp are 1 immediacy/ transient response, 2 midrange, 3 treble. Based on what I’ve read to date (mostly at AA), that fits best with OTLs, especially point 1. Any alternative views?
To Bear : Maybe is it subconscious feeling and we have it in gens - looking to hot coal by the fire and phalic shape of tubes ( people like big ones 😉 ), warmth by class A etc. Here can't any bloody transistor compete ... 😎
...sorry Upupa, not so simple! In some applications toobes be better. In some applications soylent state is more gud. There is no hard and fast rule or perfect amp for every case.
I have both, thank you. 😀
Rick57, go the way you wish... OTLs are fun.
OTLs will be sensitive to impedance, inverted as compared to a solid state amp, and again different than a tube amp... something to consider. Probably no "faster" than a solid state amp - especially if your source is a CD? That's the bandwidth limiting factor, eh? You can't get rise time faster than the sources'...
subjectively OTLs do "sound open" usually. Perhaps it is due to a reduction in bass? Perhaps not. Perhaps it is a distinctive harmonic structure.
You can't get everything.
One has to pick and chose your compromises - every speaker and every system has them. It is a matter of which ones bother you the most and which ones make you happiest.
Audiomouse - No way any pentode/tetrode will sound like a triode amp... they just don't. Not that I've ever heard in far too many years to mention. As far as getting one that sounds like dogpoop, see below...
So, if you can get a pair of those chinese amps that inexpensively, I'd give them a shot - maybe you can find a used pair in Oz? Need more extension? Put a high quality output transformer on it... modify the input... depends on what you want?
Do you want to build an amp or buy an amp?
Or are you simply trying to save money by building an amp kit??
If that's all, you might find that buying a used OTL is cheaper than a new OTL kit??
Ymmv.
_-_-bear
PS... re-read ur post Rick57... that's too expensive for chinese 300Bs, I thought you meant the whole amp! You can buy EH 300Bs new and import them for less... I see them on the ebay too.
PPS. take the cathode resistor out of ur EL-34s (assuming fixed bias) and set the bias by another means (or put in 0.1ohm resistors), strap them for triode increase the filter cap size going to the plate by 2-5x, and tell me how it sounds...
I have both, thank you. 😀
Rick57, go the way you wish... OTLs are fun.
OTLs will be sensitive to impedance, inverted as compared to a solid state amp, and again different than a tube amp... something to consider. Probably no "faster" than a solid state amp - especially if your source is a CD? That's the bandwidth limiting factor, eh? You can't get rise time faster than the sources'...
subjectively OTLs do "sound open" usually. Perhaps it is due to a reduction in bass? Perhaps not. Perhaps it is a distinctive harmonic structure.
You can't get everything.
One has to pick and chose your compromises - every speaker and every system has them. It is a matter of which ones bother you the most and which ones make you happiest.
Audiomouse - No way any pentode/tetrode will sound like a triode amp... they just don't. Not that I've ever heard in far too many years to mention. As far as getting one that sounds like dogpoop, see below...
So, if you can get a pair of those chinese amps that inexpensively, I'd give them a shot - maybe you can find a used pair in Oz? Need more extension? Put a high quality output transformer on it... modify the input... depends on what you want?
Do you want to build an amp or buy an amp?
Or are you simply trying to save money by building an amp kit??
If that's all, you might find that buying a used OTL is cheaper than a new OTL kit??
Ymmv.
_-_-bear
PS... re-read ur post Rick57... that's too expensive for chinese 300Bs, I thought you meant the whole amp! You can buy EH 300Bs new and import them for less... I see them on the ebay too.
PPS. take the cathode resistor out of ur EL-34s (assuming fixed bias) and set the bias by another means (or put in 0.1ohm resistors), strap them for triode increase the filter cap size going to the plate by 2-5x, and tell me how it sounds...
Hi there.
Bedtime reading.....thers' a OTL schematic on triode electronics site.. Go online schematics box and scroll down to RCA OTL and there it is.....worht an examination.
6082 tubes gathering rare dust.....
richj
Bedtime reading.....thers' a OTL schematic on triode electronics site.. Go online schematics box and scroll down to RCA OTL and there it is.....worht an examination.
6082 tubes gathering rare dust.....
richj
Hi,
More OTLs to be had here:
Claudio Bonavolta's Collection
http://www.bonavolta.ch/hobby/en/audio/audioel.htm#Amps
Cheers, 😉
More OTLs to be had here:
Claudio Bonavolta's Collection
http://www.bonavolta.ch/hobby/en/audio/audioel.htm#Amps
Cheers, 😉
Is commonly known, that sound results of quasicomplementary SS amps are worse than complimentary SS ones. Can somebody claim, that quasicomplimentary TUBE ones, so called OTL, haven't these disadvantages ? Plus many other disadvantages, like high inner resistance etc. Or do you like all " stone axe " ? 😀
Hi,
I see...Bad at first, even worse still after....
Good first, even better still....
Looks like it....Stone axe sounds better than metal axe.
Cheers, 😉
I see...Bad at first, even worse still after....
Good first, even better still....
Looks like it....Stone axe sounds better than metal axe.
Cheers, 😉
Bear
> Probably no "faster" than a solid state amp - especially if your source is a CD?
My source is mostly CD, some tuner. So an OTL is roughly equal: I thought SS varied somewhat in speed.
If you are right there, there’s little advantage in going OTL; but you also said OTLs are fun – what sonic qualities were you referring to?
Interesting to decipher how OTLs "sound open".
** Frank? Mohan??
A used OTL would be best value, finding one may take a while, but I’d be happy to build a goodun
Cheers
> Probably no "faster" than a solid state amp - especially if your source is a CD?
My source is mostly CD, some tuner. So an OTL is roughly equal: I thought SS varied somewhat in speed.
If you are right there, there’s little advantage in going OTL; but you also said OTLs are fun – what sonic qualities were you referring to?
Interesting to decipher how OTLs "sound open".
** Frank? Mohan??
A used OTL would be best value, finding one may take a while, but I’d be happy to build a goodun
Cheers
To Frank : Yes, it is not about objectivism, it is about faith, blind faith 😎 . In every time, when I see these graphs in magazines, which certify me, that my ears are OK and I read there, how is this thing amazing, I'm asking, who is mad. 😉
Upupa Epops said:
Upupa
"Beauty is in the eye of the beholder" Paraprhase this to ears and auditory....
Frank,
you’ve said “For anything called OTL the trick is to get the PS right . .” in the middle of this forum’s best OTL thread:
http://www.diyaudio.com/forums/showthread.php?s=&postid=354940&highlight=#post354940
What do you think are the best things to do to improve an OTL PS – improve regulation (per Futterman, Rozenberg & Croft); anything else? ie what to aim for in a PS, or maximise?
Any thoughts on how much a kit (eg Transcendent Sounds) OTL PS might benefit from such 'tweaking'?
Thanks
you’ve said “For anything called OTL the trick is to get the PS right . .” in the middle of this forum’s best OTL thread:
http://www.diyaudio.com/forums/showthread.php?s=&postid=354940&highlight=#post354940
What do you think are the best things to do to improve an OTL PS – improve regulation (per Futterman, Rozenberg & Croft); anything else? ie what to aim for in a PS, or maximise?
Any thoughts on how much a kit (eg Transcendent Sounds) OTL PS might benefit from such 'tweaking'?
Thanks
What ....... me off is a one mans thesis on the story of HiFi and how it should sound like.........there's too much wasteless holler like this about....GreggeryPeccary said:
richj
Hi,
Most of what needed to be said with regard to OTL amps is already been said in the thread you mentioned.
OTLs aren't all that different from ordinary PP amps, just look at them as if they were ordinary tube amps but with much higher current capability and running the output stage from a bipolar rail.
You'll always be limited on what you can tweak with a kit, space limitations and pcbs aren't really tweak friendly.
OTOH, should you decide for a kit and you'd like advise from me on what parts to upgrade then that's fine by me, just send me a copy of the schematic and I'll look into it for you.
Just keep in mind that I'll have to work from experience, I can't possibly predict all tweak results without ever even listening to the amplifier.
Cheers, 😉
Most of what needed to be said with regard to OTL amps is already been said in the thread you mentioned.
OTLs aren't all that different from ordinary PP amps, just look at them as if they were ordinary tube amps but with much higher current capability and running the output stage from a bipolar rail.
You'll always be limited on what you can tweak with a kit, space limitations and pcbs aren't really tweak friendly.
OTOH, should you decide for a kit and you'd like advise from me on what parts to upgrade then that's fine by me, just send me a copy of the schematic and I'll look into it for you.
Just keep in mind that I'll have to work from experience, I can't possibly predict all tweak results without ever even listening to the amplifier.
Cheers, 😉
Thanks, Frank!
You are a gentleman and a scholar. With a sense of humour to boot!
BTW, who is that gentleman in your avatar?
I considered using Otto von Bismarck, but I’m not sure that his talents overlapped with audio. In a way what I now have as avatar is the Otto of the dog world. 😉
Cheers
You are a gentleman and a scholar. With a sense of humour to boot!
BTW, who is that gentleman in your avatar?
I considered using Otto von Bismarck, but I’m not sure that his talents overlapped with audio. In a way what I now have as avatar is the Otto of the dog world. 😉
Cheers
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