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Hoffman Amps Forum image Author Topic: 5f2a mods  (Read 5099 times)

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Offline newguitarsmell

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5f2a mods
« on: February 24, 2019, 11:40:18 pm »
https://el34world.com/Hoffman/files/Hoffman_5F2A.pdf

What mods do I need to use:
El34 instead of 6V6
6SN7 instead of 12ax7

Is it possible?
Rectifier will be 5y3

Offline PRR

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Re: 5f2a mods
« Reply #1 on: February 25, 2019, 12:29:19 pm »
EL34 is much higher heater demand.

6SN7 is much lower gain.

It's really a something-else.

Offline sith

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Re: 5f2a mods
« Reply #2 on: February 25, 2019, 01:16:55 pm »
what do you plan to achieve, do you want to scratch build it or 'upgrade' exting amp?
To me, only viable differences (not upgrades, by any means) to tweed princetone circuits are using EL84 instead 6v6 for arguably different tone, rectifier - silcone vs tube, and bigger filter caps...Of all I stick to last only 

Offline newguitarsmell

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Re: 5f2a mods
« Reply #3 on: February 25, 2019, 01:34:51 pm »
Interesting comments. How much bigger filter caps and what would they do?

Is there an amp that has both a 6SN7 and el34s and if so, what is it?

Thanks!

Offline sith

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Re: 5f2a mods
« Reply #4 on: February 26, 2019, 06:04:18 am »
 you'll get more filtering and amp will (might) sound more tight,  some say modern


Offline Papa Jim

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Re: 5f2a mods
« Reply #5 on: February 26, 2019, 06:54:36 am »
one tube reverb.

Offline mresistor

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Re: 5f2a mods
« Reply #6 on: February 26, 2019, 06:54:52 am »
8wattjack is right on..   I have a 65 Champ that has vintage  10" 4 ohm Jensen black frame in it and it sounds great..  I think the speaker was reconed and changed to 4 ohm at some point. I put a huge Mercury Magnetics Champ OT in a 64 Vibro Champ that has a custom 12" speaker cabinet with an alnico 12" and it sounds like heaven.  Really chimey and clear.  Sweet..


But what is it you are trying to achieve? What sound are you looking for? I don't get the 6SN7 part, that's a low mu tube. I guess it indicates you might be wanting a clean sound. Like a 5F6A.


Are you going for single ended or open to push pull?   If SE then I would head over to Watkins SE forum and poke around.. sewatt.com
« Last Edit: February 26, 2019, 07:04:46 am by mresistor »

 


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