Dennis Had Inspire Amps

[Rosco65]

Originally Posted by david45

And I thought I was set on getting the new PSE amp...

Why not? If you need the PSE amp for the 10 watts it will give you, the 5 watt amp Analog Addict is showing won't really cut it. And if you can get by with the 5 watts, why do you need 10? From what I can see under the hood, it might be possible to incorporate Dennis' new power supply schema into the PSE, at least some variation on it.

However, I'm starting to think about Dennis' amps like Shindo amps: there are several topologies and tube types, some at similar price points, each giving a different flavor of musicality.

This is also in Dennis' system, voiced for his (and AA's) taste. You may find yourself happier with a PSE (or 45, or 2A3 for that matter).

I can't drive myself crazy looking for the next improvement in Dennis's designs. In my systems, I think I have the solution I am looking for. I can tweak what I have right now without throwing it away and getting something new.

[Analog Addict]

Originally Posted by FloridaBoy

So what does the 'rectifier' tube do in the amp?

When is a rectifier not a rectifier? When it is the Infinite Impedance Regulator! Here is Dennis' quote....

"...a new circuit I have recently developed to prevent power supply distortions caused by the output tubes pushed into high and even higher non linear levels of output power. These distortions show up as a parasitic modulation products even on the smallest forms of the power supply. The actual sonic audible indications are sharp high frequency lisps on vocals and instruments becoming strident and for a better word ear piercing. I normally let me ear be the design chain but in this case I went to test equipment spectrum displays for analysis of the power supply wave form along with the output wave for and harmonic content. My goal was to limit odd order products in the output signal and in turn discover the source of many over load distortions. What I discovered was when an output device, in my case a vacuum tube, became non-linear and produced various spurious distortion products back fed to the power supply. In the case of a basic power supply suppling both the output devices along with the driving front gain sections I was able to detect these modulated parasitic products in the driver stage compounding the problem of output distortion of the final product.

I was surprised to find the nasties invading even the regulated power supply circuit I use for the input driver tube and output tube screen grids. My thought process, (dangerous!!!) took me to figure on a high impedance decoupling device of the power supply between the output and input devices with a shared power source. Well, since I gotta lotta time to think about circuits and not banks and employees … bingo … the light went off. How about the good ole two element vacuum rectifier vacuum tube. Yea, like and indirectly heated 5AR4, GZ34 and variants …. use the vacuum between the elements and see if the good ole rectifier tube could transfer the positive going DC voltage from the high B+ output tube potential to the lower (+250 VDC) regulated driver and screen grid supply. With some additional parts and old man soldering, it works and works well. I can now drive the you know what out of a single-ended amplifier and create a listenable signal even in complete over load with the 2nd order harmonic masking the third and fifth order nasties. How does it sound …. smooth, with honey flowing from the loudspeakers. "

Originally Posted by Rosco65

Why not? If you need the PSE amp for the 10 watts it will give you, the 5 watt amp Analog Addict is showing won't really cut it.

Actually it's not a 5 watt amp. With the 6550s in it, I believe we were seeing 12 WPC before clipping. Dennis has written down a whole notebook page of measurements of wattage and quiescent current, etc. I will ask him to send me a picture of it, and I will post it....

[FloridaBoy]

Originally Posted by Rosco65

Why not? If you need the PSE amp for the 10 watts it will give you, the 5 watt amp Analog Addict is showing won't really cut it. And if you can get by with the 5 watts, why do you need 10? From what I can see under the hood, it might be possible to incorporate Dennis' new power supply schema into the PSE, at least some variation on it.

However, I'm starting to think about Dennis' amps like Shindo amps: there are several topologies and tube types, some at similar price points, each giving a different flavor of musicality.

This is also in Dennis' system, voiced for his (and AA's) taste. You may find yourself happier with a PSE (or 45, or 2A3 for that matter).

I can't drive myself crazy looking for the next improvement in Dennis's designs. In my systems, I think I have the solution I am looking for. I can tweak what I have right now without throwing it away and getting something new.

Agreed. I done starting all over. None of these amps are 'bad'.

[Rosco65]

Originally Posted by Analog Addict

When is a rectifier not a rectifier? When it is the Infinite Impedance Regulator! Here is Dennis' quote....

"...a new circuit I have recently developed to prevent power supply distortions caused by the output tubes pushed into high and even higher non linear levels of output power. These distortions show up as a parasitic modulation products even on the smallest forms of the power supply. The actual sonic audible indications are sharp high frequency lisps on vocals and instruments becoming strident and for a better word ear piercing. I normally let me ear be the design chain but in this case I went to test equipment spectrum displays for analysis of the power supply wave form along with the output wave for and harmonic content. My goal was to limit odd order products in the output signal and in turn discover the source of many over load distortions. What I discovered was when an output device, in my case a vacuum tube, became non-linear and produced various spurious distortion products back fed to the power supply. In the case of a basic power supply suppling both the output devices along with the driving front gain sections I was able to detect these modulated parasitic products in the driver stage compounding the problem of output distortion of the final product.

I was surprised to find the nasties invading even the regulated power supply circuit I use for the input driver tube and output tube screen grids. My thought process, (dangerous!!!) took me to figure on a high impedance decoupling device of the power supply between the output and input devices with a shared power source. Well, since I gotta lotta time to think about circuits and not banks and employees … bingo … the light went off. How about the good ole two element vacuum rectifier vacuum tube. Yea, like and indirectly heated 5AR4, GZ34 and variants …. use the vacuum between the elements and see if the good ole rectifier tube could transfer the positive going DC voltage from the high B+ output tube potential to the lower (+250 VDC) regulated driver and screen grid supply. With some additional parts and old man soldering, it works and works well. I can now drive the you know what out of a single-ended amplifier and create a listenable signal even in complete over load with the 2nd order harmonic masking the third and fifth order nasties. How does it sound …. smooth, with honey flowing from the loudspeakers. "







Actually it's not a 5 watt amp. With the 6550s in it, I believe we were seeing 12 WPC before clipping. Dennis has written down a whole notebook page of measurements of wattage and quiescent current, etc. I will ask him to send me a picture of it, and I will post it....

My implication was the comparison of a 10 watt PSE using 6V6 tubes and a single SE using 6V6. I would imagine the PSE with KT88's would run 18-20 watts.

Dennis's design appears to be compensating for the additional distortion obtained from pushing tubes for higher output. It would be interesting to compare the two circuits - normal Firebottle and Hotrod - when run at a lower power level, say the aforementioned 5wpc 6V6 application (assuming they both share the upgraded parts selection the Hotrod seems to enjoy). It would also be interesting to compare a 12wpc KT88 with Dennis new PS and a 15wpc KT88 PSE (5U4) OR compare a 6L6GC with the new PS with a PSE 6L6GC. With levels matched, I would expect the PSE to require less heroics to control distortion products. That being said, the question remains if we are able to achieve similar levels and spectra of distortion is there a sonic advantage of use a single tube with enhanced PS over the PSE with standard regulated PS? Secondarily, would we expect to see similar advantages applying this PS to the PSE?

Power supplies are interesting animals; in the end they are what drives our speakers. There appear to be a number of paths to sonic Nirvana. Some designers use minimalist power supplies (Sun Audio, Wavelength, Fi) while others devote the majority of their efforts to the PS with the remaining amp circuitry almost an afterthought (Border Patrol).

[BearCityUSA]

Originally Posted by Rosco65

My implication was the comparison of a 10 watt PSE using 6V6 tubes and a single SE using 6V6. I would imagine the PSE with KT88's would run 18-20 watts.

Dennis's design appears to be compensating for the additional distortion obtained from pushing tubes for higher output. It would be interesting to compare the two circuits - normal Firebottle and Hotrod - when run at a lower power level, say the aforementioned 5wpc 6V6 application (assuming they both share the upgraded parts selection the Hotrod seems to enjoy). It would also be interesting to compare a 12wpc KT88 with Dennis new PS and a 15wpc KT88 PSE (5U4) OR compare a 6L6GC with the new PS with a PSE 6L6GC. With levels matched, I would expect the PSE to require less heroics to control distortion products. That being said, the question remains if we are able to achieve similar levels and spectra of distortion is there a sonic advantage of use a single tube with enhanced PS over the PSE with standard regulated PS? Secondarily, would we expect to see similar advantages applying this PS to the PSE?

Power supplies are interesting animals; in the end they are what drives our speakers. There appear to be a number of paths to sonic Nirvana. Some designers use minimalist power supplies (Sun Audio, Wavelength, Fi) while others devote the majority of their efforts to the PS with the remaining amp circuitry almost an afterthought (Border Patrol).

Rosco,

Your mind when just where mine did. This seems mostly a revision to his power supply circuit and not necessarily an entirely new typology end to end. I received the same explanation as Analog last evening from Dennis with one additional bit directed at me. He will be wiring my PSE with this new Infinite Impedance Regulator which I will pick up later this month. My understanding of this all is so limited I seem to just put my trust in Dennis. If he says it will be better I say OK, I'm with you. I like his ear. For those of you, me included in that I have no plans to part with my 2013 KT, which are curious about this latest tweak but not interested in more equipment I get the feeling that this could be a mod to your existing FireBottle. I am sure we will know more soon as this develops.

Scott

[Rosco65]

Scott,

Would you be willing to share Dennis' response regarding your PSE?

Thanks,
R

[CoGT3]

Analog and BearCity,
Are you restricted to using indirectly heated rectifiers with the "infinite impedance regulator"? And does he expect as much change from rolling rectifiers as with a traditional PS circuit? Or another to ask, what effect does the V drop of the rectifier seem to have on the new circuit or the output tubes used (still need 5Y3 with 6V6G?)?

Curious as I will be joining the PSE crowd later this year to compliment my 45 SET. Have already started to collect some rectifiers and output tubes.

[Analog Addict]

Originally Posted by CoGT3

Analog and BearCity,
Are you restricted to using indirectly heated rectifiers with the "infinite impedance regulator"?

Yes, unless you want to get some serious hum in your signal. This would essentially limit you to 5V4s and 5AR4s, except for some esoteric tubes I know nothing about.

Originally Posted by CoGT3

And does he expect as much change from rolling rectifiers as with a traditional PS circuit?

You would think not, but we tried a fancy CV something or other rectifier tube in the circuit, (perhaps a CV378) and Dennis didn't like it, and switched back to the 5V4G

Originally Posted by CoGT3

Or another to ask, what effect does the V drop of the rectifier seem to have on the new circuit or the output tubes used (still need 5Y3 with 6V6G?)?

No. The B+ voltage is being reduced differently by the flavor of rectifier, but the downstream regulated voltage is far lower, so the small difference in upstream voltage drop is negligible. That being said, see answer above....

[BearCityUSA]

Originally Posted by Rosco65

Scott,

Would you be willing to share Dennis' response regarding your PSE?

Thanks,
R

After explaining why he did not join these discussions directly this is what Dennis emailed last night.

"Anyway I wanted to let you know your new PSE will have a new circuit I have recently developed to prevent power supply distortions caused by the output tubes pushed into high and even higher non linear levels of output power. These distortions show up as a parasitic modulation products even on the smallest forms of the power supply. The actual sonic audible indications are sharp high frequency lisps on vocals and instruments becoming strident and for a better word ear piercing. I normally let me ear be the design chain but in this case I went to test equipment spectrum displays for analysis of the power supply wave form along with the output wave for and harmonic content. My goal was to limit odd order products in the output signal and in turn discover the source of many over load distortions. What I discovered was when an output device, in my case a vacuum tube, became non-linear and produced various spurious distortion products back fed to the power supply. In the case of a basic power supply suppling both the output devices along with the driving front gain sections I was able to detect these modulated parasitic products in the driver stage compounding the problem of output distortion of the final product.

I was surprised to find the nasties invading even the regulated power supply circuit I use for the input driver tube and output tube screen grids. My thought process, (dangerous!!!) took me to figure on a high impedance decoupling device of the power supply between the output and input devices with a shared power source. Well, since I gotta lotta time to think about circuits and not banks and employees … bingo … the light went off. How about the good ole two element vacuum rectifier vacuum tube. Yea, like and indirectly heated 5AR4, GZ34 and variants …. use the vacuum between the elements and see if the good ole rectifier tube could transfer the positive going DC voltage from the high B+ output tube potential to the lower (+250 VDC) regulated driver and screen grid supply. With some additional parts and old man soldering, it works and works well. I can now drive the you know what out of a single-ended amplifier and create a listenable signal even in complete over load with the 2nd order harmonic masking the third and fifth order nasties. How does it sound …. smooth, with honey flowing from the loudspeakers.

Yesterday afternoon, I had the opportunity to have Audio Addict over for a listening session. We had a blast listening for hours at extremely high levels with various tube combos. As Alan coined it … “honey flowing with those trumpets”. Then off to the test gear …. no matter how hard I drove the new “Hot-Rod” Inspire, the second harmonic remained predominate at full clipping. Oh, and the DC bias current on the 6550’s did not budge with this new power supply circuit.

Soooooooo, Scott, a new circuit is born … at least with me … I call:

infinite impedance regulator power supply circuit

Maybe you could pass on the technical info .. "




I do not think there is much more, if anything, here than what Analog posted.

Scott

[CoGT3]

Originally Posted by Analog Addict

Yes, unless you want to get some serious hum in your signal. This would essentially limit you to 5V4s and 5AR4s, except for some esoteric tubes I know nothing about.





You would think not, but we tried a fancy CV something or other rectifier tube in the circuit, (perhaps a CV378) and Dennis didn't like it, and switched back to the 5V4G

Just got a CV593 which = GZ32/5V4G. So that might fit the bill.

No. The B+ voltage is being reduced differently by the flavor of rectifier, but the downstream regulated voltage is far lower, so the small difference in upstream voltage drop is negligible. That being said, see answer above....

What do think about adding this power circuit to the 45 SET? Seems like you would get the same benefit as with the lower powered SE pentode amps, cleaner break up when pushed? Also BearCity mentioned Dennis will be wiring his PSE up with this circuit. With the large output of the PSE relative to the 45 SET, would think it be as beneficial if your are not pushing the PSE hard? (Using 96dB speakers)?