Seven pin follies

[PlumMojo]

Anyone have experience using exotic phase splitters?

Like seven pin tubes?

I see that 6j6 (i see its 5v filaments also) is a dual triode anyone experience it's tube flavor???


Any and all info highly welcome.

What to do with these seven pin tube sockets ?

Submit all drawings please

[sluckey]

There are plenty of 7 pin tube circuits in guitar amps. Search the forum for "7 pin" (include the quotes in the search). Also, look through the schematic library linked at the bottom of this page. 6AT6, 6AV6, 6AQ5 are some common 7 pin tubes. There's even a complete amp that uses only 7 pin tubes on the forum. Learn how to use the forum search function to open many doors to 7 pin follies and much more.

[kagliostro]

I see that 6j6 (i see its 5v filaments also) is a dual triode anyone experience it's tube flavor???

5v ??? NO, 6J6 is a 6.3V heater tube



Franco

[brewdude]

My latest build is all 7-pin tubes.  It’s inspired by the early Gibson GA-40 Les Paul amp.  It is a single channel with out the tremolo. Two 5725 pentodes in the pre amp, with a tilt (big muff) style tone control, a 6C4 cathodyne PI and a pair of 6AQ5’s.


I have made a few adjustments since the schematic was last updated:
Gain—1M A.
Tone—2M B, with two .001uF caps and a bypass switch.
PA Cathode—110R (to bias with plate dissipation at ~97%).
Added .1uF cap at the input (to eliminate guitar volume pot scratchies).


It’s a fun amp. 

[PlumMojo]

Indeed I really really need to get my forum game up.

I am unschooled in etiquette as well as general functionalities.

Thanks guys.


Brewdude!!AMAZING!!!

Also Idk were i seen 5v from

Sorry and thanks for the correction

[brewdude]

Brewdude!!AMAZING!!!

Thanks.
I see that Kagliostro posted a link to my AG thread on the other 7-pin topic.

[PlumMojo]

Dual rectifier tube huh?
That's a cool looking schematic!

[brewdude]

Thanks,
The two rectifiers were used because one 6X4 would not handle the current I expected to draw—one of the goals of this build was to use only 7-pin tubes.


Regarding the schematic, I like using colors, it helps me organize and follow the schematic and the designs intent.

[PlumMojo]

That's really really cool.

I enjoy all aspects of what your doing.

I can appreciate all of it.

So how is the final palate compared to the world over 12AX7?

[brewdude]

Honestly, I don’t really know how to describe the differences between 7-pin and 9-pin tubes or if one could likely tell the difference.  Pentodes do tend to have a different character than triodes, some describe it as “sweeter”, but I’ve never really understood what that meant.  I have felt at times that larger bottles sounded “bigger” but honestly I can not hear this amp as sounding “smaller”. 


Whatever it is that makes this amp satisfying to me—pre amp pentodes, 7-pin tubes, large inductor CLC filter, choke fed screens, tilt tone control, relatively low power and VVR—it’s simple to operate and fun to play.


By the way, I have never been in the same neighborhood as an original early ‘50s GA-40 and have no reference to compare this amp to. 

[brewdude]

May be a couple months late, but here is a video demo of my seven pin amp. 
https://youtu.be/7lTzMwUxbwc

[shooter]

here's a 29pin build I did with 7 & 8 pinners