A good sounding EL34 PP sch please

[Audiofanatic]

Hi,

I mean this one.

Best,

Audiofanatic

[cjkpkg]

Here is an up to date layout of the schematic that I etched...

The only thing I did before etching is make the ground traces a little wider with a sharpie.

I still had to bend the octal socket leads around a little to get them to fit nicely for soldering.

Oh, and I did not adjust the grid stopper as advised in the above post yet either....

You may also want to draw a little more "meat" for the B+ inlet - I went from PSU to board 1 then from board 1 ran a wire to board 2...did this for ground also...

I also since moved the initial power resistors from the bottom of the board to the topside - may want to consider 3W or maybe 5W...I used 2W panasonics...

[Audiofanatic]

Audiofanatic

[woodturner-fran]

cjkpkg - thanks for posting this!

I have some dynaco output iron gathered for this, 8k impedance and 4&8R taps. Good for 80mA a side so I'm hoping they will be good enough for this amp. I'll have to decide yet on whether to go PCB or just P2P, have to see what sockets I have!!


Fran

[cjkpkg]

No problem!

Yes I love this amp...I did the boards primarily because of the coupling caps...If I had chosen auricaps with insulated flexible leads I could have utilized my original aluminum plate idea...Buying the boards and 8 sockets was less than 8 auricaps though...

80mA should be just fine...I run 89 per channel and it sounds nice...

I am running the original feedback scheme with the voltage divider on the speaker outputs to ground. I want to try the 3K feedback resistor to the driver tube sometime.

[woodturner-fran]

Iron - check
Valves - check
Chassis - check
Most components - check

Ordered sockets tonight, hope to order the rest of the parts soon.....

Then to build!

Fran

[woodturner-fran]

Sockets delivered today...

Iron is all mounted, and power supply pretty much sorted. I will use DC heaters for the 6SN7s (12v with 2 tubes in series) and AC for the EL34s. I'm using those fairchild stealth diodes for the B+ rectification..... and probably russian K40y caps for the interstage caps.


Fran

[cjkpkg]

Excellent Fran!

That is exactly how I am running mine...regulated DC on the 6SN7's and A/C on the EL34's.

I love the k40y9's.

[woodturner-fran]

Did you ever go back and d the modified feedback with the pos and neg feedback to the driver 6SN7 cathodes?

I think I'll start off by doing mine standard, but maybe with the led on the input cathode. KISS and all that.....


Fran

[cjkpkg]

I have not! Too many projects...I an knee deep in a CCDA phono stage that I am getting close on...

I ran it for a while with no feedback and it actually sounded quite nice. Now it has the 1K resistors off each of the speaker terminals running to ground. I just havent gone back to disconnect it too see if my memory is that good...

You might try it with no feedback first...then work your way up to running it back to the driver tubes...