Hi,
One of the first who deisgned a SE amp with 6C33C was Mr Dakesue in Japan. I built a kit designed by him using the 6C33C. According to Mr Dakesue the 6C33C sounds best at relatively low anode voltage ~200V and 200mA current with 600 ohm load.
http://www2.gol.com/users/tube/se.html
If the dissipation in a 6C33C is kept below 40W or 2/3 of max the life time is very long.
I have had no problems with valve sockets in my SE amp, (>6 years) or my OTL, (> 4years).
BTW, Miller capacitance is not so high in these tubes as u is very low.
Regards Hans
One of the first who deisgned a SE amp with 6C33C was Mr Dakesue in Japan. I built a kit designed by him using the 6C33C. According to Mr Dakesue the 6C33C sounds best at relatively low anode voltage ~200V and 200mA current with 600 ohm load.
http://www2.gol.com/users/tube/se.html
If the dissipation in a 6C33C is kept below 40W or 2/3 of max the life time is very long.
I have had no problems with valve sockets in my SE amp, (>6 years) or my OTL, (> 4years).
BTW, Miller capacitance is not so high in these tubes as u is very low.
Regards Hans
I thought is was very good even compared to other SE amps using 300B and 2A3, also when comparing to quite high end solid state amps, (Electrocompaniet, Luxman, Sunfire and others) most people listening noticed that the sound was smoother and the SE amp didn't add any thing bad sounding to the music, especially compared to a high spec Luxman the sound was very smooth and nice and the problems with the Luxman especially really showed themselves, (the person owning the Luxman sold it shortly afterwards as he was so disappointed)
However, as all SE amps I have heard this amplifier also mask some details in the music, I believe this is due to high 2nd order distorsion and IM that is also quite high, at least much higher then in many other non SE amps...
After building my OTL amp I really heard what was missing with the SE amp and for me SE amps is a dead end, I have also compared my OTL with other SE amps of good reputation but the result is the same.
Maybe what I described above will invite a lot of bashing but I stand firm in my belief of OTL amp superiority over SE amps until someone convince me of the opposite.
Regards Hans
Konnichiwa,
No bashing or the like intended, but I would like to know a little more about the system context (especially speakers) and your seating preferences in the concert hall (I like "Mid-Hall" Center best), assuming you include classical music (fresh and converve) in you musical diet.
Would you mind telling? It might give a better context to place your comments in.
My experience with OTL's was not as favuorable as yours. The OTL's where Croft Monoblocks, 4 X EL509/519 Output Valves per channel. I have also had a chance to hear later Croft OTL's based on the 6AS7 and in both cases I noted a number of performance areas where the Transformer coupled SE and PP DHT Amplifiers at had where by far superior (especially low level detail retrieval).
Of course, it may very well be that Crofts are simply bad OTL's or simply that I enjoy a little 2nd Harmonics from an SE Amp (but why then do I like all transformer coupled PP DHT Amp's equally well?) or I just like having transformers in the signal path.
Sayonara
tubetvr said:
No bashing or the like intended, but I would like to know a little more about the system context (especially speakers) and your seating preferences in the concert hall (I like "Mid-Hall" Center best), assuming you include classical music (fresh and converve) in you musical diet.
Would you mind telling? It might give a better context to place your comments in.
My experience with OTL's was not as favuorable as yours. The OTL's where Croft Monoblocks, 4 X EL509/519 Output Valves per channel. I have also had a chance to hear later Croft OTL's based on the 6AS7 and in both cases I noted a number of performance areas where the Transformer coupled SE and PP DHT Amplifiers at had where by far superior (especially low level detail retrieval).
Of course, it may very well be that Crofts are simply bad OTL's or simply that I enjoy a little 2nd Harmonics from an SE Amp (but why then do I like all transformer coupled PP DHT Amp's equally well?) or I just like having transformers in the signal path.
Sayonara
Hi,
About the worst OTL Glenn ever did IMO but with some modification you could make it into a great little OTL.
Mine is the Series II which uses 10 //ed 6080s but I had trouble with the main PS for the tubes as he had put 100Vers in series to create 200V caps.
I had them replaced with 250 V Mallorys of similar total value and haven't had problems since.
He also derives the bias for the output stage from the negative rails which is IMO cutting a corner whith a highish risk factor.
Sonically the Series II is very hard to beat but from reading you it may well be not your cupper.
Cheers,
About the worst OTL Glenn ever did IMO but with some modification you could make it into a great little OTL.
Mine is the Series II which uses 10 //ed 6080s but I had trouble with the main PS for the tubes as he had put 100Vers in series to create 200V caps.
I had them replaced with 250 V Mallorys of similar total value and haven't had problems since.
He also derives the bias for the output stage from the negative rails which is IMO cutting a corner whith a highish risk factor.
Sonically the Series II is very hard to beat but from reading you it may well be not your cupper.
Cheers,
Konnichiwa,
They where a friends, re-build powersupplies, rebuild signal circuit with some of Glens own mods from later series, Multicap for coupling and fancy resistors et al. So basic circuit was still Glenn, but a sligthly later generation, the rest re-build.
BTW, my friend still owns them but no longer uses them, he prefers 2A3 & 300B transformer and inductive/direct coupled Amplifiers he build from my designs.
The 6080/6AS7 ones I heard had only 4 valves per monoblock and where very recent, about a year back, maybe a little longer. They where some of the last ones with the ugly wooden frontpanels and bog standard stock.
Hmm, it seems the amp's you had where different from those I heard. Anyway, I'm just curious. I also heard the Atma Sphere Circlotorn Amp's and hear the same forced, uneasy quality and "in your face sound" I heard from the Crofts and which I would charaterise as "OTL" Sound, based on my experience so far.
I will admit that I rather like the idea of an OTL Amp, except I wish they could sound more to my taste than these I heard did. I have been thinking 6S33 SRPP with a Ongaku style driver and classic output coupling cap. In the end all the "OCL" OTL Amp's merely replace the coupling Cap with a pair of PSU Cap's and usually not very good ones. If I have to deal only with around 200V DC and a dozend volt AC I can make up a 2000uF Poly Cap in about the same size case as a nice OPT might fit in.... It'd probably cost more than a decent SE OPT too.
Or maybe an inverted Futterman based around the Ongaku frontend? A little NFB in either case, just enough to lower the Z-Out to a level comparable to my DHT SE & PP Amp's, this could be attached to the middle stage, rather than to the input stage and add to that another loop from the middle stage anode to the input stage cathode, rather than one "long" NFB loop....
Sayonara
fdegrove said:
They where a friends, re-build powersupplies, rebuild signal circuit with some of Glens own mods from later series, Multicap for coupling and fancy resistors et al. So basic circuit was still Glenn, but a sligthly later generation, the rest re-build.
BTW, my friend still owns them but no longer uses them, he prefers 2A3 & 300B transformer and inductive/direct coupled Amplifiers he build from my designs.
fdegrove said:
The 6080/6AS7 ones I heard had only 4 valves per monoblock and where very recent, about a year back, maybe a little longer. They where some of the last ones with the ugly wooden frontpanels and bog standard stock.
fdegrove said:
Hmm, it seems the amp's you had where different from those I heard. Anyway, I'm just curious. I also heard the Atma Sphere Circlotorn Amp's and hear the same forced, uneasy quality and "in your face sound" I heard from the Crofts and which I would charaterise as "OTL" Sound, based on my experience so far.
I will admit that I rather like the idea of an OTL Amp, except I wish they could sound more to my taste than these I heard did. I have been thinking 6S33 SRPP with a Ongaku style driver and classic output coupling cap. In the end all the "OCL" OTL Amp's merely replace the coupling Cap with a pair of PSU Cap's and usually not very good ones. If I have to deal only with around 200V DC and a dozend volt AC I can make up a 2000uF Poly Cap in about the same size case as a nice OPT might fit in.... It'd probably cost more than a decent SE OPT too.
Or maybe an inverted Futterman based around the Ongaku frontend? A little NFB in either case, just enough to lower the Z-Out to a level comparable to my DHT SE & PP Amp's, this could be attached to the middle stage, rather than to the input stage and add to that another loop from the middle stage anode to the input stage cathode, rather than one "long" NFB loop....
Sayonara
Hi,
Surely you don't want me to tell you what's in the signal path of an SE amp?
Either way, what's important is the endresult and I never had the impression I was listening to 2 pairs of 4000µF electrolytics....Let's not forget either that this is a PP amp.
Since Nicos was asking me somewhat the same I did a little write up on life with OTL amps here:
CROFT SERIES II OTL.
Maybe I shoul also put that sticker up my bumper stating:
"My other amp is a 2A3 PP"
Which just so happens to be the absolute truth...
Cheers,
Surely you don't want me to tell you what's in the signal path of an SE amp?
Either way, what's important is the endresult and I never had the impression I was listening to 2 pairs of 4000µF electrolytics....Let's not forget either that this is a PP amp.
Since Nicos was asking me somewhat the same I did a little write up on life with OTL amps here:
CROFT SERIES II OTL.
Maybe I shoul also put that sticker up my bumper stating:
"My other amp is a 2A3 PP"
Which just so happens to be the absolute truth...
Cheers,
Konnichiwa,
No, I happen to know. For the output stage one transformer (hopefully a good quality one - in which case it presents no material sonic problems), one Valve and one PSU decoupling or WE connection capacitor closing the output signal current loop. if you have any more there you simply show how it should not be done.
Mine is a 45 PP, at the moment, but I can make it 2A3 PP or 300B PP, as I please... ;-)
Sayonara
fdegrove said:
No, I happen to know. For the output stage one transformer (hopefully a good quality one - in which case it presents no material sonic problems), one Valve and one PSU decoupling or WE connection capacitor closing the output signal current loop. if you have any more there you simply show how it should not be done.
fdegrove said:
Mine is a 45 PP, at the moment, but I can make it 2A3 PP or 300B PP, as I please... ;-)
Sayonara
At home I use Lowther Fidelio and as you I like mid-hall center best when listening to live classical music. I have a relatively wide taste of music, including classic music, (especially piano music) jazz, classic soul and classic pop.
I also used other speakers at when comparing amplifiers including some larger Audiovector model, (that I borrowed from a friend) and Quad ESL63. Regardless of speaker, I can quite easily here details in some recordings using my OTL amp that is masked by the SE amps I have compared to, I have also been running around in the high end shops in Akihabara and elsewhere here in Tokyo and been listening to many SE amps with different speakers, by using the same CD's I am used to listening to at home I have come to the same result, i.e that SE amps hide details in some music.
I am quite surprised about the result myself as many people rave about SE amps but probably that is becaused SE amps make almost all recordings sound good, with an OTL amp you get to hear everything including bad recordings.
Regards Hans
Hi,
Well if you jump to the conclusion that the PSU is in the direct signal path of the OTL circuit then it's just as easily said that the PS is in the signal path of a SE amp...
After all, DC has to be stopped somewhere and with most OTL/OCLs I know of it's the opposing +/- rails that allow the extraction of the AC signal without DC riding along with it.
BTW, I may have said this before, a very close friend of mine owns a set of AN Baransus and Lowthers.
They sound fine even though I hear them humming on quiet passages but I'd never dream of using them in my system as they really don't offer anything the OTL can't do better.
This, regardless of cost which let's face it, skirts the absolutely ridiculous.
Cheers,
Well if you jump to the conclusion that the PSU is in the direct signal path of the OTL circuit then it's just as easily said that the PS is in the signal path of a SE amp...
After all, DC has to be stopped somewhere and with most OTL/OCLs I know of it's the opposing +/- rails that allow the extraction of the AC signal without DC riding along with it.
BTW, I may have said this before, a very close friend of mine owns a set of AN Baransus and Lowthers.
They sound fine even though I hear them humming on quiet passages but I'd never dream of using them in my system as they really don't offer anything the OTL can't do better.
This, regardless of cost which let's face it, skirts the absolutely ridiculous.
Cheers,
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