10 band EQ all tubes

[Osvaldo de Banfield]

I'm 51, you?

Why not to consider compactron tubes? there is a large stock of them, with very interesting characteristics and many of them are cheap.

 

[Kay Pirinha]

Yes, there's also a Compactron triple triode that actually is three halves of a 12AX7. I've seen it in some Fender amplifiers of the 1980ies. Sadly I don't remember it's designator and I also don't know if it is cheap enough .
Best regards!

 

[Osvaldo de Banfield]

6AC10. A 12AX7 and half at a single heater powering cost. Excellent. And combinations of 12AU7´s and 12AX7´s in single envelope, like 6U10.

 

[Kay Pirinha]

Not exactly, Osvaldo! IIRC there's a Compactron triple triode with a µ of 100 for all sections.
Best regards!

 

[kissabout2002]

I'm 51, you?

Why not to consider compactron tubes? there is a large stock of them, with very interesting characteristics and many of them are cheap.

I am 60 that's why when you call me boy I felt good....lol....I am not familiar with compactron tubes but I will consider use them in future....all the best

 

[32860]

IIRC there's a Compactron triple triode with a µ of 100 for all sections.
Best regards!

This may be useful:

 

[Osvaldo de Banfield]

I am being familiar with them. They are pretty fine.

 

[stocktrader200]

interesting project, I would use KSC1845 for U3 - U12 and the follower positive supply to + 40v with a dropping resistor (10k) and capacitor.
Much easier to implement, tube sound comes from the gain stages

 

[Kay Pirinha]

I think I'll have to dig out the schematics of the Fender amplifier that I mentioned. Then I can tell the one-and-a-half 12AX7's designator for sure .
Best regards!

 

[Osvaldo de Banfield]

6C10 from the below table. But it is expensive. Less used triple triodes or double triodes plus diodes (6B10, 6AG11) and double pentodes are very useful. 6BF11 is a pretty pentode/tetrode combination, and has a very interesting hysteretic behavior in the pentode's screen and suppressor grids:
Delayed relay pentode driven

 

[Kay Pirinha]

Thanks, Osvaldo, this is the tube!
Have I told you yet that I'm not that familiar with compactrons, as they aren't exactly familiar in Europe? I regard that as a pity, as they apparently are really interesting tubes. Oh, and they look sexy, too .
Best regards!

 

[Osvaldo de Banfield]

OK. It is intriguing for me why European manufacturers didn't adhere to the compactron idea. It is very useful.

 

[Kay Pirinha]

They went another way: Keeping B9A/Noval for small signal and low power tubes, swapping for Magnoval for higher power ones when International Octal went out of fashion.
Big tubes like PL519/40KG6A per manufacturers' advice need to be prevented from falling off their sockets. I guess this wasn't necessary for Compactrons due to three additional pins and a superior diameter to height ratio?
As said several times: It's dissappointing, at least for me, that Compactrons never were common here, hence aren't that easily to acquire, for not to speak on one Euro lists .
Best regards!

 

[Osvaldo de Banfield]

Although the outline characteristics are different, the real advantage is inside the glass. There are some uncommonly high pentode, like the one designed for TF video IF with 30mS of transconductance, triple of the EF183/4 pair. Don't being remembering now the part name.

 

[Kay Pirinha]

In Europe there were for video amplifier services the tubes PFL200 (21 mS), PCL200 (28 mS) and PL802 (40 mS) as the final developments. Televisions with them usually had pictures with more contrast than those with their predecessors (PCL84, PL83). Especially PCL200 is an interesting tube, as it's triode exactly is half a 12AT7. PL802 has become scarce and expensive for some time, but seems to be available again nowadays for decent money.
Best regards!

 

[Osvaldo de Banfield]

Sorry, I never saw them here.
I read several weeks ago that Zenith or General Electric has developed a dual compactron set for AM table radios, one with converter and FI, the other, audio pre and output, and the diode. And there?

Multi-Function Compactrons Promise Two-Tube Radio | Electronic Design

and others.

 

[Kay Pirinha]

Very interesting, as of July 23, 2000 !
Best regards!

 

[Osvaldo de Banfield]

I found the site where I learn about the two compactron radio set. here is it:

Compactrons: Advance in Tube Design, October 1960 Electronics World - RF Cafe

I have a friend here in Argentina that in the 70's, working for General Electric, made the service manuals in Spanish for this radios.

 

[kissabout2002]

The Blonder-Tongue Audio Baton replica on the way, I just finished one channel and test it.

I stick to the original schematic but I add a 5 led bar graph, led VU meter and an unusual power supply that works very well.

The second channel will be upside down for fit inside a 3U cabinet and when finish will looks as the picture of the front panel. Both channel will be completely independent.

Sound is excellent just some minor noise issue but I will work out on it, this is just the first test.

All the best to everybody.

 

[gideon1990]

Have you managed to tame that switcher? I have the same one in the junkbox but it is quite noisy