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  »  New  A different breed of 6C33C amplifier...  6C33C mono block @ clipping...  Melquiades Amplifier  Forum     84  521946  09-06-2011
04-12-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 1
Post ID: 10215
Reply to: 10215
More 6E5P-6C33C amps.
fiogf49gjkf0d

I have no idea why this guy is and what he says, I even have no idea of what language it is but here it is: the 6E5P-6C33C amp in PP configuration.

http://drzlab.com/projekti/TPPP_6c33c.html

Interesting that he uses Russian military Teflon caps that I found to be very bad sounding but this guys open them up and do something with them. I have no idea what as I can’t read it.

http://www.moxtone.com/PTFE_COND.htm

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-12-2009 Post does not mapped to Knowledge Tree
jp
Posts 39
Joined on 02-25-2006

Post #: 2
Post ID: 10216
Reply to: 10215
Try this
fiogf49gjkf0d
Apparently, its Croatian

http://translate.google.com/translate?hl=en&sl=hr&u=http://drzlab.com/projekti/TPPP_6c33c.html&ei=if7hSafGPKftlQeon9zgDg&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3Dhttp://drzlab.com/projekti/TPPP_6c33c.html%26hl%3Den%26rlz%3D1G1GGLQ_ENUS322%26sa%3DG
04-12-2009 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,079
Joined on 10-12-2006

Post #: 3
Post ID: 10218
Reply to: 10215
Antenna?
fiogf49gjkf0d
It looks like he stripped off the outer jacket and the end caps and removed the pole posts, so he now has the cap equivalent of a "naked resistor", like the parts geeks drool over.

I dunno, but looking at the naked cap, I wonder how firmly and evenly it was wound to begin with.  It has always been my understanding that the winding itself is a big issue with caps.

My neighbor is Serbian; I'll see if he reads techno.

Seems like a good basic concept for a laconic PP amp, though...

Paul S
04-13-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 4
Post ID: 10222
Reply to: 10218
I do not like this basic concept of PP amp.
fiogf49gjkf0d

 Paul S wrote:
Seems like a good basic concept for a laconic PP amp, though...

The fix bias of  driver and out stages are fine. Why he need to have 1:8 input transformer. The driver stage does 32 time gain, the output stage does 3 time. Is it not enough?  Does he has his speakers with sensitively of 85dB and 2000 cub feet room? I think for the gain he made with 1:8 input transformers I think the amp will not have enough power. However, the biggest thing that I do not like in there is the PP concept itself. In this PP implementation the out tubes shall be match super prissily and it is imposable with 6C33C. Even if you do match them initially then the different 6C33C age with different tempo. The only way to use them in PP is to use automated base that make the 6C33C to sound like wet dog, courtesy to BAT and others. So, I am not so impressed with what this guy does. Still his use of 6E5P makes him deserved to be mentioned. I do not know what result he gets from this amp. Even if I was able to read his text then I would not believe that he say anything about sound. As I underrated he is from DiyAudio.com site and those people know only about soldering and measuring but they are clawless about Sound.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-13-2009 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,079
Joined on 10-12-2006

Post #: 5
Post ID: 10224
Reply to: 10222
Good Point
fiogf49gjkf0d
- and a very important point - about "matching" the 6C33C halves.  I never thought of that, which is funny since I use the 6C33Cs myself and can't find actual matches anywhere (except for a pound of flesh, from VL, of course).  And, as you note, the inevitable drift would make it a problem, sooner or later, even if the tubes were "matched" to begin with.

Still, I wonder if there is a better way to handle a sliding bias...

Best regards,
Paul S
07-27-2009 Post does not mapped to Knowledge Tree
vuki


zagreb, croatia
Posts 4
Joined on 05-04-2008

Post #: 6
Post ID: 11199
Reply to: 10222
Drz
fiogf49gjkf0d
Hi!

Sorry for not spotting this thread before.
I'm the member of this forum and I read it from time to time. I don't know what do you mean with "he is from diyaudio.com site"? I'm member of a few formums and newsgroups but I wouldn't say that I'm from any of them.
Regarding my amp; the input transformer is rewired to get 1:4 ratio, the driver stage has gain of <30, and output has about 3, which gives approx. 90x gain, than comes opt which cuts gain back with its transforming ratio. Gain of the complete amplifier is about 14. I use transformer attenuator passive preamp. My speakers are altec based 2way and Tannoy hpd385. You can see the speaker projects on my pages under "zvucnici". 
It does sound very good. As you can see I also have 300b SE amp. f2a PP amp, and some solid state designs. I regulary have opportunity to compare my projects with commercial and DIY stuff from my friends. For a few years I've also been (please restrain yourself from vomiting, Romy) chief editor of the croatian audio magazine "Hi-Fi", and I'm still using those "connections" to get new commercial equipment for home listening.
Anyway, my plan was to make powerful triode NFBless amplifier for relatively small money. I'm really satisfied with what I did. Maybe I should have done GM70 SE, but what would be my next project then?

Regards,
Vuki


  
07-27-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 7
Post ID: 11200
Reply to: 11199
Bang for back?
fiogf49gjkf0d
 vuki wrote:
Anyway, my plan was to make powerful triode NFBless amplifier for relatively small money. I'm really satisfied with what I did. Maybe I should have done GM70 SE, but what would be my next project then?
The GM70 is a bitch and I do not think you will be able to get away with her with relatively small money. It is not to mention that I never heard good amps on GM70. You have already the 6E5P input stage and it can with a single 6E5P stage to drive the GM70 to 36-40W. Juts power your GM70 with a lab PS and see how it goes. The question is why do you need more power – to driver bass section because you have a large room? Great! Go DSET! With DSET you will have relatively small money spent regardless what kind powerful tube you will be using. You can plug 211/845/GM70 or even GU48 with $200 worth output transformer and get a LOT of juice and 10Hz of full SET power. Still, if you are juts with two Altec-based drivers then they are not truly DSET required and probably to go ways with a single amps is would be better idea. I personally instead of making more powerful triode NFBless amplifier would rather add two more drivers to the Altec. It would give me more bang for back.

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
07-28-2009 Post does not mapped to Knowledge Tree
vuki


zagreb, croatia
Posts 4
Joined on 05-04-2008

Post #: 8
Post ID: 11205
Reply to: 11200
Tao
fiogf49gjkf0d
I completely agree with what you said. To tell you the truth I was already very satisfied with sound, but I just wanted to make that powerful triode amplifier - I really don't need it. But it's nice to have it. As you know in this hobby it's not so much about the end of the road but more about getting to it. So there is probably no audiophile who, from time to time, doesn't want to try something new. If audio electronics is your hobby then even more so. Audiophile who is completely satisfied with the sound of his system doesn't have the perfect system - he just gave up searching for it.  That is why I would probably also make GM70 SE amplifier. Just to enjoy making it and then tweaking it's sound.
Regarding your suggestion for additional drivers- that would be great only when they wouldn't need so huge enclosure volumes. But I already have a pair of 604-8k's ready for the next project. The problem is I'm running out of space for all those loudspeakers and my wife isn't so enthusiastic about them. Anyway, I bought them to hear how they sound because there are no many Altecs here in Croatia so buying them was my only option to hear them.

Best regards,
Vuki   
07-28-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 9
Post ID: 11207
Reply to: 11205
Not so much about the end of the road but more about…
fiogf49gjkf0d
 vuki wrote:
To tell you the truth I was already very satisfied with sound, but I just wanted to make that powerful triode amplifier - I really don't need it. But it's nice to have it. As you know in this hobby it's not so much about the end of the road but more about getting to it. So there is probably no audiophile who, from time to time, doesn't want to try something new. If audio electronics is your hobby then even more so. Audiophile who is completely satisfied with the sound of his system doesn't have the perfect system - he just gave up searching for it.  That is why I would probably also make GM70 SE amplifier. Just to enjoy making it and then tweaking it's sound.

You pretty much answered your own question you asked above about me characterizing your approach as “typical diyaudio.com”.  I do not find the “itchy soldering” and senseless “trying something new” as a stimulating activity for myself. You might as well buy a $20 Casio piano, attach it’s keys to a generator of random numbers and begin to “compose music”. Anyhow, I do not try to convince you in anything, you do whatever makes you happy.  I just saying that I have zero interest in what you recognize as your hobby and I presume that many design decisions you made while you designed your 6E5P-6C33C amp were upon fatly premises (from my point of view). It is very typical for most of the Audio DIYers,

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-25-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 10
Post ID: 14783
Reply to: 10215
The Greek’s Praxis double-stager.
fiogf49gjkf0d

It is nice to see the de-centresation of audio manufacturing. Formerly US, UK, Germany, France, a few Scandinavians and off the wall Japanese were making high-end audio.  Today the lead positions in interesting high-end audio have moved to Poland, Bulgaria, Korea, Greece, Lithuania and few other countries that 10 years ago were not big on the world hi-fi map. That is very good. I can talk a lot about the reasons but I am sure that not the last of the reasons that English-writing audio publications idiots who have been fucking up public audio intellect for years, did not yet learn nether Bulgaria nor Lithuanian…

Anyhow, here is another interesting product from Greece.  The company Cosmos audio Labs and they have 2-stage SET with “my” 6C33C.

http://www.cosmosaudiolabs.com/products.html

A pleasant design and a present implementation. I have no idea what another 6C33C does in the back of the amp – is it a regulator for PS or what? The description does not say anything about it. The driver is 7721. This is very good tube, I used it in output of my phonocorrector. I am not sure if I like it as a driver for two-stage amp. The 7721 has very little power but the 6C33C would like to be pushed very hard. If someone from Greece then pitch to the Cosmos people my 6E6P, it is the same pins, practically the same gain but it would run 8W as a driver. I think that 15W that they specify are mostly restricted by clipping of the driver stage – I am sure they might use more current on the driver.

Sure it turns me off that they provide Frequency Response not at full power – to me this is an indication of evil-minded stupidity. Still, I would like to hear the amp and to learn more about the design. If it will be distributed in US then let me know.

Romy The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-26-2010 Post does not mapped to Knowledge Tree
Cosmos
Posts 3
Joined on 10-26-2010

Post #: 11
Post ID: 14793
Reply to: 14783
Praxis SET
fiogf49gjkf0d

Dear Romy, thank you so very much for mentioning our amplifier to your excellent forum. Indeed, during the last 5-6 years there are a lot of manufacturers “from non traditional hi-fi manufacturing countries”. In particular, in poor old Greece we are more than 50-60 very small companies building some interesting audio products even with the extremely awkward local financial situation which is leading to extinction a lot of us.

Anyway, as the description on our site on second paragraph says, the third 6C33 located at the back, is used as the pass element of the regulator (controlled by solid state circuitry) providing 220V with 100uV of random noise & Hum at full load with very low and uniform, across the audio band, output impedance.

On the other hand, 7721 was chosen amongst many other driver tubes tested including 6E6P-DR and 6E5 too. To tell you the truth I really liked 6E6 but the gain was lower than needed and after 1 year on the test amp it started to degrade in sound and characteristics. Also 7721 (specified for 10000hours service life which is good for a commercial design) seem to my ears marginally more analytical than 6E6, though 6E6 had marginally better articulated bass. 7721 is not a small tube at all and at 170V(at anode) and 14mA (triode strapped) provides very low distortion even at full power. In any case the circuit can easily accommodate 6E6 with very minor internal adjustments (though no soldering is needed).

The quoted 15W of output power is restricted only by the distortion characteristics of 6C33, if you do not mind higher distortion (say 7-8%) the output power can reach easily 20 or more watts. Moreover, because of the adjustable regulator, someone may increase voltage, from 220VDC specified, to 230 or more and play with the operating point, but the sound is not that correct to my ears, I really prefer 220V @ 210-220mA but my taste is just my taste.

You are correct though that frequency response is not at full power and you can be assured that I am not at all evil minded as I am not stating that the response is at full power. The frequency response stated is measured at 8W@8Ohm done just for ease of measurement as the 8V mark on my millivoltmeter happens to be right above the 0db mark. For your information, I just measured the actual full power bandwidth at 15W and it is -3dB from 9Hz to 122KHz  which is not bad and not very much different from what it is stated at our site and very respectable for a zero feedback SET amplifier. This good bandwidth is the product of good old transformer calculation and construction execution using a total of 10 primaries and 5 secondaries carefully layered. The core is of type E120 with 8cm of laminations providing a total of 10H gapped for 250mA. 

On the other hand, we got no distributor in the US yet, as we launched our products in Munich Hi-End Show (together with Tune Audio Anima speakers) in May and had no contacts or interest from any US distributor.

Sorry for the long post,

Remaining at your disposal for any questions you may have

Sincerely,
Panos
10-26-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 12
Post ID: 14795
Reply to: 14793
To regulate or not regulate 6C33C
fiogf49gjkf0d
 Cosmos wrote:
Anyway, as the description on our site on second paragraph says, the third 6C33 located at the back, is used as the pass element of the regulator (controlled by solid state circuitry) providing 220V with 100uV of random noise & Hum at full load with very low and uniform, across the audio band, output impedance.
 
I see, you regulate outs tube. This is interesting. The best SET I heard with 6C33C (Lamm ML2.0) also use regulated output stage. There were a lot of debates on Russian forums about a need to regulate 6C33. I did not use 6C33 as regulator but I was trying to power 6C33 from a regulator on 3 paralleled 807 triodes along with a fast pentode areal amplifier. I experienced a slight improvement in low level details and more interesting lower end harmonics but I did lose a bit dynamics. At that time I was trying to improve over ML2.0 dynamics, so I figured the regulation is not my direction and went for choke regulation that I feel is faster. Can you express your view over regulated 6C33C vs. unregulated?
 Cosmos wrote:
On the other hand, 7721 was chosen amongst many other driver tubes tested including 6E6P-DR and 6E5 too. To tell you the truth I really liked 6E6 but the gain was lower than needed and after 1 year on the test amp it started to degrade in sound and characteristics. Also 7721 (specified for 10000hours service life which is good for a commercial design) seem to my ears marginally more analytical than 6E6, though 6E6 had marginally better articulated bass. 7721 is not a small tube at all and at 170V(at anode) and 14mA (triode strapped) provides very low distortion even at full power. In any case the circuit can easily accommodate 6E6 with very minor internal adjustments (though no soldering is needed).

The 7721/7788 are a wonderful tubes, my favorite high mu penthodes I use a single 6E6P to drive my tweeter (107dB sensitive ribbon via 1:175 transformers) and I did tried in there 7721.  It is 200V and 35mA. Do you feel that you do not need power in your driver? Gains is fine but gain without power is not good. Are you sure that your driver stage dose not clip. The reason I ask is because my 7721 had around 2.5V of bias with grounded cathode. This is very low bias as today DACs will out 5-6 V at 0dB. I would also disagree with your sentiments about the long service. Yes, the 7721 will live for very long time but they are long out of production and they are around $30. The 5E5P/6E6P are dirt cheap. Yes they will not last more than one year but frankly speaking so the 6C33C… Anyhow, I am not trying to convince you in anything o it is your amp. BTW, if you feel that 6E6 has more articulated bass then try Melquiades type of bias – what it make with bass will make you to lough…
 Cosmos wrote:
You are correct though that frequency response is not at full power and you can be assured that I am not at all evil minded as I am not stating that the response is at full power. The frequency response stated is measured at 8W@8Ohm done just for ease of measurement as the 8V mark on my millivoltmeter happens to be right above the 0db mark. For your information, I just measured the actual full power bandwidth at 15W and it is -3dB from 9Hz to 122KHz  which is not bad and not very much different from what it is stated at our site and very respectable for a zero feedback SET amplifier. This good bandwidth is the product of good old transformer calculation and construction execution using a total of 10 primaries and 5 secondaries carefully layered. The core is of type E120 with 8cm of laminations providing a total of 10H gapped for 250mA. 

Panos, to specify frequency response of 15W amp and to use 8W as referent is as use as measure sensitivity of loudspeaker but use an arbitrary distance for microphone. It must not be doe under any circumstances and I wish you manufactures get it. Do you know that my car get 150 miles per gallon. Oh, I forgot the say that my mile is 3 inch and my gallon is 54 litters… How is it useful? Also, with all due respect I do not believe that you have -3dB from 9Hz to 122KHz  at full power. Absolutely imposable!!! The best you can get is juts under 20Hz and somewhere around 20kHz -22kHz. If you deny it then you do not measure properly.

Rgs, Romy the caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-27-2010 Post does not mapped to Knowledge Tree
Cosmos
Posts 3
Joined on 10-26-2010

Post #: 13
Post ID: 14797
Reply to: 14795
Regulator?
fiogf49gjkf0d
My Dear friend Romy,

Indeed it took me a very long time to decide upon regulate or not. I ended up with regulation option to save some chassis space and weight, otherwise I would need at least 10 kilos more and 30% bigger space that would make the whole amp impossible to move and redicoulously big for a 15 watter. On the other hand regulation is good for a commercial machine since its easier to live with less adjustments for the final user, moreover the sound of the regulator is very similar with slightly better detail and bass, however chokes provide slightly easier and softer sound to my ears, but there are times you got to make some choices and regulator was mine.

I really like your prototype approach on biasing your driver but have not test it, so I cannot comment but I will take your words that it is excellent, however this is your patent and I would never mess with somebody elses mental property, though I will test it at some point and let you know my views.

You are absolutely right on frequency response method of testing and I will correct my site asap, however that was not at all intentionally as expalined in my previous post. On the other hand my measurements are correct and really do not understand why you do not believe these, just for your information my equipment is recently calibrated and are the following, tektronix SG502 signal generator, HP3478A, Fluke 8840A, Fluke 8060A, HP400H, tektronix D15 and 561A, these are used for measurement of frequency and Vrms and also EMU0202 as spectrum analyzer. Note also that the load used for these measurements is a 50W 8ohm power resistor. If you would like me to measure something else please be my guest. I really do not get why you are saying that the response you are getting is only 20-22KHz, maybe your output transformers are not up to the task? Maybe I can help you on that.

Thanks again, my best regards,

Panos
10-27-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 14
Post ID: 14799
Reply to: 14797
If not then all bets are off
fiogf49gjkf0d
 Cosmos wrote:
Indeed it took me a very long time to decide upon regulate or not. I ended up with regulation option to save some chassis space and weight, otherwise I would need at least 10 kilos more and 30% bigger space that would make the whole amp impossible to move and redicoulously big for a 15 watter. On the other hand regulation is good for a commercial machine since its easier to live with less adjustments for the final user, moreover the sound of the regulator is very similar with slightly better detail and bass, however chokes provide slightly easier and softer sound to my ears, but there are times you got to make some choices and regulator was mine.

Yes, chokes would make the amp bigger and they toss a lot of shaking inductivity around that stress chassis a lot. The choke regulating is most likely goes with two chassis configuration that automatically trigger much higher price for a commercial product. Still, leaving the economy aspect aside, I heard that the supporters of regulation feel that there is some not economic but sonic advantage to have 6C33C regulated. Well, I guess we can learn the final judgment about it in our next lives…. BTW, if you have a regulation on board then it would be very easy for you to implement a switch for one heater operation for 6C33C…
 Cosmos wrote:
You are absolutely right on frequency response method of testing and I will correct my site asap, however that was not at all intentionally as expalined in my previous post.

Be very careful with that. Since you are a manufacturer then your job is not to demonstrate sanity but to compete with idiots who claim that their 6C33C amp can run a video signal. They just forgot to mention that it will do it at .00000001W…
 Cosmos wrote:

On the other hand my measurements are correct and really do not understand why you do not believe these, just for your information my equipment is recently calibrated and are the following, tektronix SG502 signal generator, HP3478A, Fluke 8840A, Fluke 8060A, HP400H, tektronix D15 and 561A, these are used for measurement of frequency and Vrms and also EMU0202 as spectrum analyzer. Note also that the load used for these measurements is a 50W 8ohm power resistor. If you would like me to measure something else please be my guest. I really do not get why you are saying that the response you are getting is only 20-22KHz, maybe your output transformers are not up to the task? Maybe I can help you on that.  

Might be I do need a help what I witnessed is what I report upon and what I believe to. The 20-22KHz response is incredibly good response at full power for full-range 6C33C SET amp. Most of the SET amps do not go even close to it. This conflict between inductance and capacitance in SET transformer is the bitch for SET design and this is why I went DSET. Frequency response of SET amp I mostly restricted by OPT and the only know to me objective way to measure the frequency response of a transform is a full power. I uselessly set my SET into symmetric clipping at 1000Hz (by current and voltage) and then drive input signal to the level just below the clipping. This I consider a full power and ALL measurements of frequency response I do ONLY at this level. Then I roll the generator down until I get a 0.1-0.2 dB less. This is the beginning of the LF roll off.  Then I roll the generator down more until I hit -3dB. This is the LF cut off frequency. Then I do the very same foe HF and the only things change is the timing in my scope. I have seen very few SET amps that do 20-20K at full power. The 9Hz to 122KHz is absolutely imposable bandwidth in my view. I have in my LF channel run to 7.5Hz but it uses a transformer with very high inductance, mass and size, much- much higher than your 10H. The  transformer is7.5Hz-800Hz and this is DSET transformer, it has no sections on secondary and case less about capacitance as it works only on LF. I did not see any transformer that has all provisions for maintaining HF and minimum HF phase shift and at the same time to be able to get down to 9Hz.   I my only presumption is that you are the amp full power. Again, I do not care how many watts it is – it MUST be juts under the clipping. If not then all bets are off. This is how I see the things.

Rgs, Romy the Cat




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-28-2010 Post does not mapped to Knowledge Tree
Bud
upper left crust united snakes
Posts 87
Joined on 07-07-2005

Post #: 15
Post ID: 14806
Reply to: 14799
Actual SE OPT prformance limits
fiogf49gjkf0d
Hi Panos,

Romy asked me for a sanity check on your stated performance limits for your SE OPT's. It is good to see someone paying some attention to what is in the Radiotron Designers Handbook for high performance coils. What you are doing, winding five coils and stacking them up the central core shaft of core is not done very often outside of radio frequency transformers, in this "modern" age. Are you using a tape wound cut core or E/I laminations, or perhaps L core? If you are using commercial grade E/I core I can suggest a distributed gap, utilizing three gap sectors. For lowest distortion above 250 Hz any core form that shoves the gaps out beyond the coil winding limits is a plus. This can be done with tape wound cores, but it is a pain, becomming either a J core or, in your case, having 3 coils on one side and 2 on the other of a central cut gap, with about 3mm of distance from the coil winding edge to the gap. Stick winding all five coils is also a possibility, though nearly a lost art now days.

Were it me , I would find a way to mold a CE 6500 style shrouded bobbin. One for each Primary, Secondary, Primary coil set, and make use of the inherent safety agency delight and greatly enhanced control over the E Field moments provided by a complete dielectric enclosure. If you have access to vacuum polyester resin impregnation you can then construct a dielectric circuit to better focus the E Field across the dielectric barriers. This will roughly triple your coherent information transform and provide you with a startlingly dense signal retention. Will also allow the plates to work more efficiently.

So, yes Romy, it is quite likely that Panos is actually building OPT's that will allow his tubes to remain stable enough to provide the frequency response he is claiming. The only down side I see is the fiendishly complicated interconnect between the coils and then making that entire event something that the EU safety agencies will allow him to sell commercially, in the EU community. Not beyond possibility, but only commercially viable where labor costs are quite low.

Bud
10-28-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 16
Post ID: 14807
Reply to: 14806
Sorry, I do not believe in it.
fiogf49gjkf0d
I do not know Bud. I report only what I see and I believe in what I experience. Almond all SETs that I personally have heard the Lamm ML2.0 had the widest subjective frequency range.  I did measured how ML2.0 clip and it was at 18Hz at the bottom and a bit under 21Hz at the top (and it is WITH use of feedback!!!).  I personally never saw wider bandwidth transformer for SET.  Have hear many people made claims that this transformers run wider band but as soon I went deeper with them I always learned that they did not mean full range.  In my book if a person uses frequency response not at full range then it is absolutely meaningless.   A SET transformer has a few defining characteristic and -0.1dB frequency response at max symmetric power, combined with the gap size are pretty much encompass all of them. It is possible that you and Panos do use some kinky forgotten techniques and are informed about the way how to make a SET transformer to be 10Hz-100,00kHz at full power but I did not see it and do not believe in it. Sorry. Point it a manufacture whose SET does have those characteristics and I willing to bet money that it will be another “oops, it was at 25% of power…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-14-2010 Post does not mapped to Knowledge Tree
Cosmos
Posts 3
Joined on 10-26-2010

Post #: 17
Post ID: 14943
Reply to: 14807
Transformers
fiogf49gjkf0d

Dear Romy,

Obviously it is impossible to convince you upon the frequency response of our transformers and in any case that is fine with me since everybody is entitled to its own assumptions and opinions and this is not bad at all, on the contrary, I love different opinions.

However, let me illustrate some very-very basic and obvious knowledge-strategies that we used for these transformers, not at all kinky but sometimes forgotten (some times intentionally).

In low rp tubes and especially as low as 6C33 which is sub 100Ohms, our design is intentionally targeting on decreasing leakage inductance in expense of increased inter-winding capacitance.

Specifically, our output transformers may well have several nano-farads of inter-winding capacitance but the leakage inductance is only 1,5mH.

The above, in conjunction with ultra low 6C33(sub 100ohm) plate resistance, allows a transformer construction with -3db at more than 100KHz. Thing which is completely impossible to accomplish with almost any other tube, even with 300B (with a lowish 800ohm rp), no matter how well the transformer is calculated and executed.

The only viable possibility to construct a transformer for 300B with 100KHz + response is to make the transformer so small that the bass will be almost absent.

Of course your ideal implementation of DSET is capable of producing even more impressive results, but unfortunately this is not a design to be used for general commercial use.

My Best Regards,
Panos
11-15-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 18
Post ID: 14949
Reply to: 14943
A TV single in SET amplifier.
fiogf49gjkf0d
Panos,
 
it is not about convincing me. My standing is absolutely irrelevant in this subject – I do not sell audio and do not making living by evaluation of SET amplifiers.  I report what I have witnessed, nothing more. Sure, it is very possible that you use the winding technique that took the 6C33 transformer response to be able to transmit TV single and this is fine. I did not see and I do have some suspicions (circumstantial suspicions I have to admit) that response of your amp is not as wide as you described. For instance any person who does measure the FULL power response would not care about -3db but would care where the transformer only begin to roll off, sort of proverbial 0.1dB. Anyhow, your transformer does whatever it does, so good for him, but I think I am within my constitutionals rights to have my suspicions, am I?

Yes, the 6C33 has low plate impedance. Not always “sub 100ohm” and to be sub 100R you need to fry it at 320-330 mA. All that it does makes the transformer to have less turns with all consequential benefits. So, you have no cupper and less ability to grow inductance for LF, so you need a larger core mass. The larger core mass make larger winding with filling and spreading problems as there are not a lot of turns. Anyhow, I of course still admit the lower plate impedance tubes allow to have wider bandwidth of OPT but I would also insist that it has no practical significance.  The low Rp 6C33 with 500kHz DSET transformer would not sound as interesting in HF as type 10 tube with Rp sub 10.000R and a transformer that would have a millions turns. so, it is not as straight forward.

In context of this thread – I do like the 6C33 and since for you the interaction at this site has purely marketing objective I wish to your amp a worm reception and good sale. Honestly, if I had it them I would try the 6E6P instead of 7721, but this is me and I like the 6E5P/6E6P sound….

The Cat
 


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
03-12-2012 Post does not mapped to Knowledge Tree
decoud
United Kingdom
Posts 237
Joined on 03-01-2008

Post #: 19
Post ID: 17959
Reply to: 14949
6e5p-GM70
fiogf49gjkf0d
Not quite on topic but perhaps this deserves to be here:

http://www.theaudiophile.net/threads/762-Lyrita-s-new-Mono-amps-and-DHT-Preamp?p=7735#post7735

It appears to be a simple two stage SE design with the 6e5p coupled to the GM70 via an interstage transformer.
03-12-2012 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,407
Joined on 05-27-2004

Post #: 20
Post ID: 17960
Reply to: 17959
The 6e5p as driver for GM-70.
fiogf49gjkf0d
Yes, decoud, the 6e5p-GM70 is an easy amp but 6e5p is a hell of voltage driver and I do not feel that a single 6e5p will be able to drive GM70 into grid currents.  If people use dead speakers and need a lot of power than use the ability of direct heated GM70 to jump into A2 is given for them. If they use a single 6e5p then they have no current at 35mA and if they get current by transformer then they have no gain in the amp. So, I do not feel that 6e5p-GM70 two stages is an optimum solution. They might try to parallel a few 6e5p then it will be something more interesting, even though I do not like to parallel tubes, particularly the Russian tubes.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
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