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I made a full function integrated 6GB5 PPP. It does everything I want, even play music. I'm never gonna make another, it's too complicated for me.
31 tubes, phono preamp, tone controls, loudness, but the audio path can be as short as voltage amp - phase splitter - output.

That is beautiful!

Magnificent. An eventual heirloom piece.
Output transformer primary impedance?

Edcor 100 watts at 2.2K.

Beautiful AND great engineering

Seriously good engineering, both design and construction - something to be very proud of, I am very impressed and I'm a professional design engineer who often does design reviews of other engineers designs, so I'm not easily impressed.

The EM87 Indicator circuit looks more complicated than is generally required - what were your design intentions/requirements for this?

Should we "Nit Pick" this superior design or just sit back and admire (with envy)? - well Ok, safety resistors from the bias pot wipers to raw bias supply side of the bias pots could be added.

Cheers and Happy Xmas to all.
Ian

P.S. For here in South Oz it would have to be a winter time amp - not even mid summer here yet and we have just suffered thru' 5 days of 42 to 44 degrees C (108 to 111 degrees F), too f..ing hot to run my tube amp and I won't lower myself to hooking up the old SS Amp. I suppose I could put the system on just before dawn when temps dropped to 32C (90 F). Record for December since records where first kept. Makes me a bit cross with the Golbal Warming nay sayers, but 5 days of that leaves you fairly stressed anyway.

Gingertube wrote:The EM87 Indicator circuit looks more complicated than is generally required - what were your design intentions/requirements for this?

I made a 1625 oddwatt with a eye tube, a 6AF6. Since the input varies from about 1.5VPP to 2.5VPP, you have to be able to display as much as possible and gently limit the display to keep it from crossing. The 6BN8 is a voltage amplifier, and rectifier. The 680K and 0.1uf cap gives me the display speed I want. A EM87 should have a 100K resistor on it's pentode, but I found a 470K, at least for me works better. The 220K and zener is a soft limiter. I have 10 EM87s and 6 6BN8s, all of them were different. I had to mix and match to get these 2 similar (the colors are a bit different). I don't show the diode on one the 2 EM87s cathodes, and 220ohm resistor on the other.

Gingertube wrote:Should we "Nit Pick" this superior design or just sit back and admire (with envy)? - well Ok, safety resistors from the bias pot wipers to raw bias supply side of the bias pots could be added.

I do have them installed, forgot to draw them.

I edited the schematic, I also forgot the grounds for the phase splitters.

It gets really hot after a while. I think I'll put in a 140mm fan underneath.

That is an amazing project and so cool an different. It's like building a calculator from TTL-ICs. A
I am deeply impressed.
When I looked up the power tubes I notisen that they are equivalent to EL500 or 6p36s, Russian tubes and I have bunch of these. However I had someting much simpler in mind.

The EL500 is a good tube for PP, seems close to the EL12.

This is my first amp using the Triode Loadline Simulator v.0.2 on DiyAudio.

Words escape me its so so beautiful

There are in Baxandall filter two caps 33 nF. Maybe left is 33 nF and right 3.3 nF?
Thanks in advance.

I've seen where they are different, this one is a Morgan Jones tone control, and he seems to just pour the current on and damn the torpedoes. It does work very well, but I'm sometimes getting a oscillation in the right channel when turned all the way down. I think it's the 6EJ7.