Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: rzenc on May 27, 2021, 08:19:02 am

Title: Twin amps - 5C8/5D8
Post by: rzenc on May 27, 2021, 08:19:02 am
Hi there,


I'm planning a new build, however still on doubt which would be the way to go...


Little background info:


I do love the 5E9-A tremolux and so a friend who plays on a blues/country band. Since he needs a louder amp, he asked whether I could build him a 100W version fo the 5E9-A. After studying the schems I found the Twin 5C8 and 5D8 to be somewhat close to the 5E9-A. The idea is to keep the paraphase inverter and add a full TMB tonestack. I know the 5C8 employs octal types and that would be "upgraded" - lacking a better word now - to 9 pins.


The build will take place on a existing chassis.


I would like to know whether you guys have built one - or possibly both  :icon_biggrin:  - versions of the Twins and what are your impressions on the circuit.


I have added the link to the mentioned schems.


Thanks in advance.


Best Regards,


R.


https://el34world.com/charts/Schematics/files/Fender/Fender_tremolux_5e9a.pdf (https://el34world.com/charts/Schematics/files/Fender/Fender_tremolux_5e9a.pdf)


https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5c8_schem.pdf (https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5c8_schem.pdf)


https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5d8_schem.pdf (https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5d8_schem.pdf)


Title: Re: Twin amps - 5C8/5D8
Post by: sluckey on May 27, 2021, 10:06:22 am
Neither of those twins are anywhere near 100 watts. More like 30 watts. Since your friend likes the Tremolux I would rather put a line out jack on the speaker output and use that to drive a 100 watt power amp (even SS).

If you really want a 100W Fender amp, you'll need to step up to 4 x 6L6s, fixed bias, and a LTP PI.
Title: Re: Twin amps - 5C8/5D8
Post by: SILVERGUN on May 27, 2021, 11:27:27 am
In my mind, the High Powered Tweed Twin is just begging to be built. It's got the TMB but runs a LTP PI
It ain't 100 watts, but I don't think anyone will care. I also don't think anyone needs to be any louder than this.
What a cool amp.


FENDER.PDF (el34world.com) (https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5f8a.pdf)
Title: Re: Twin amps - 5C8/5D8
Post by: PRR on May 27, 2021, 01:03:45 pm
Quote from: SILVERGUN on May 27, 2021, 11:27:27 am
FENDER.PDF (el34world.com) (https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5f8a.pdf)

Well, isn't that 5F8a "just" a 5F6a Bassman with a doubled-up power section and different speakers?
Title: Re: Twin amps - 5C8/5D8
Post by: SILVERGUN on May 27, 2021, 01:19:56 pm
Quote from: PRR on May 27, 2021, 01:03:45 pm
Quote from: SILVERGUN on May 27, 2021, 11:27:27 am
FENDER.PDF (el34world.com) (https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5f8a.pdf)

Well, isn't that 5F8a "just" a 5F6a Bassman with a doubled-up power section and different speakers?
Why yes,,yes it is.
Ever since you touted the 5F6a as a "perfect amp" I stopped looking. I just figured out a way to make it sound like it was my idea.
And, I just wanted to get rzenc's friend closer to his 100W dream.


This is my found example of "perfect" tone:
https://www.youtube.com/watch?v=Y0r1kVXSX3Q (https://www.youtube.com/watch?v=Y0r1kVXSX3Q)
Title: Re: Twin amps - 5C8/5D8
Post by: rzenc on May 27, 2021, 05:50:13 pm
Quote from: sluckey on May 27, 2021, 10:06:22 am
If you really want a 100W Fender amp, you'll need to step up to 4 x 6L6s, fixed bias, and a LTP PI.


Hi Steve,


The amp he brought in to this conversion is a 4x6L6GC, complete with P.T., O.T. and choke.


I believe you suggested a LTP PI + fixed bias due to signal swing at the grids of power tubes?


Quote from: SILVERGUN on May 27, 2021, 11:27:27 am
In my mind, the High Powered Tweed Twin is just begging to be built. It's got the TMB but runs a LTP PI
It ain't 100 watts, but I don't think anyone will care. I also don't think anyone needs to be any louder than this.
What a cool amp.


I have a 5E9-A tremolux (cathode biased 6V6), 5E3 also cathode biased 6V6 and a 6V6 cathode biased Bassman. He played all of them...power wise they are about the same and he liked the 5E9-A better...I don't know if it has something to do with the paraphase P.I., maybe...Then he asked to build it with enough power to play loud gigs...around 100W give or take...
Thanks for your suggestion, I might build me one of those someday...I have a 100W set of iron laying around  :icon_biggrin:


Quote from: PRR on May 27, 2021, 01:03:45 pm
Quote from: SILVERGUN on May 27, 2021, 11:27:27 am
FENDER.PDF (el34world.com) (https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5f8a.pdf)

Well, isn't that 5F8a "just" a 5F6a Bassman with a doubled-up power section and different speakers?


I always looked at it like this....but never got to hear one personally. Glad you brought this up.


Quote from: SILVERGUN on May 27, 2021, 01:19:56 pm

And, I just wanted to get rzenc's friend closer to his 100W dream.



Many thanks for your inputs SG!! And thanks for sharing the video too.


I have a strange idea...will draw it and come back to share with you guys




Thanks a lot!!!!!


Best Regards


R.

Title: Re: Twin amps - 5C8/5D8
Post by: tubeswell on May 27, 2021, 07:04:55 pm
Make it a 5F8A and you will have no regrets


here's our Swedish friend