Does someone has a schematic for the Zeppelin Percolator ?

[Kagliostro]

Does someone has a schematic for the Zeppelin Percolator 2W amp ? (it uses a 6AF11 compactron tube)

With the 6AF11 tube a known and well documented amp is the Squirrel Monkey

http://solorb.com/elect/musiccirc/squirrelmonkey1/

I'm looking for the Zeppelin Percolator amp schematic, the Percolator uses the same Compactron 6AF11 tube

https://zeppelindesignlabs.com/product/ ... w-amp-kit/





Many Thanks

K

[pompeiisneaks]

Although they don't have a schematic that I see offhand, they actually sell it as a kit and ahve full instructions on assembly with pictures etc:
https://www.zeppelindesignlabs.com/wp-c ... CTIONS.pdf

and the site for the kit:

https://zeppelindesignlabs.com/product/ ... w-amp-kit/

page 39 has a photo of the circuit board, and may allow you to somewhat reverse engineer it?

~Phil

[Kagliostro]

Ciao pompeiisneaks

Thanks .... I've all that documentation and may be something more (about the use of that 6AF11 tube)

But I would like to see the Percolator schematic or, at least, know which are the Voltages on PS and the primary impedance of the OT

However Many Thanks for your contribute

Franco

[didit]

Hello -

Illustration on page 39 does provide voltages with documented test points. Appears it's 170V B+1, which seems sensible. Don't worry much on the output primary and life will be fine. With the provided BOM and that illustration one should readily be able to sketch out the schematic.

Best .. Ian

[Kagliostro]

Ciao Ian

Illustration on page 39 does provide voltages with documented test points. Appears it's 170V B+1

I missed that info

Many Thanks

Franco

[didit]

Ciao .. Ian

[vintagekiki]

https://music-electronics-forum.com/sho ... hp?t=50811

https://www.scribd.com/document/4536589 ... tor-ZDL-2W

[didit]

https://music-electronics-forum.com/sho ... hp?t=50811

https://www.scribd.com/document/4536589 ... tor-ZDL-2W

Nicely done ..

[Kagliostro]

Many Thanks vintagekiki

Based on my 35 years engineering experience, I tried on basis of photos to find common point, and as result is schematic that is located in front of you.

so I would like to ask you ....

in the web I've find indications that say that the primary impedance of the OT is 6K (the autor told guessed it, didn't had the data)

Based on B+ and max plate dissipation I guessed a similar value

Based on your knowledge which will be the value of the primary impedance on the Percolator ?

Thanks

Franco

[vintagekiki]

Kagliostro
... which will be the value of the primary impedance on the Percolator ...

The Compactron Dual Triode-Sharp-Cutoff Pentode 6AF11 is not an audio tube, it is a tube used in TV applications.
There are no applications developed for use 6AF11 in audio techniques, so any output transformer impedance 2.5 to 6 kohm can be used.
When choosing, use the transformer that gives best power adjust.

http://www.nj7p.org/Tubes/PDFs/Frank/123-GE/6AF11.pdf

http://www.junkbox.com/electronics/Comp ... ndex.shtml
http://www.angelfire.com/vt/audio/compactron.html
http://www.solorb.com/elect/musiccirc/squirrelmonkey1/

[Kagliostro]

Ciao vintagekiki thanks for answering

I was asking because I have find on the web some different solutions

The Squirrel Monkey use a 3.5K OT (and the autor talk about 0.8W output if I'm not wrong)

A radio project from Popular Electronics january 1963 uses 10K OT

The Percolator uses an OT of which I don't know the primary impedance, but it is declared for 2W of output power

All uses similar B+ voltages (from 170V to 180V DC)

I've find a thread where someone reverse engeenered the Percolator and guessed a 6K load for the Power Pentode

I did a bit of math and arrived to a similar conclusion

Plate dissipation of the pentode is 5W ( assuming to use 4.5W max as to a conservative dissipation) so if Z = Va^2 / Pa

170V x 170V = 28,900

28,900 / 4.5W = 6,422 Ohm Load (not very far from the guessed 6K)

Franco

[didit]

Hello --

Scribbling a bit working off data sheets available a good spot would be ~7-9K. However, worry less build more. That pentode has nice dissipation and gain characteristics. Stuffing all these various levels of signal into such a small bubble seems most challenging.

Best .. Ian

[Kagliostro]

Ciao Ian

With the help of a friend I'm arranging a personal circuit that uses the 6AF11 tube

still in work, I'm considering some options but till now not convinced at 100% with anyone

Many Thanks for the info, 7-9K Load, and what about the B+ level you considered on compute ?

Franco

[martin manning]

If I could choose freely, for SE I would go with 225 Va, 125 Vg2, and a 10k load, bias at 20-22 mA. Output power is 1.8W on paper. If you have some other plate voltage in mind you can adjust the load for that using Va^2/Pa = Zpri.

[didit]

Working roughly with what we know of Zeppelin at 170V. Martin shares his homework in much better detail, and doubtless used something more sophisticated than an envelope while eyeballing curves. We both landed in the same ballpark.

Best .. Ian