Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on February 24, 2020, 04:25:41 am

Title: Paralleled V1 (6AK5) Tube + TS -- 2 or 3 Tubes must be used to drive enough TS ?
Post by: kagliostro on February 24, 2020, 04:25:41 am

My laboratory (Garage) is still cluttered with materials due to the home renovation that I have done,
so, waiting for it to be free and that it can use it, I am thinking of something to give a try

--

Some time ago, from a Stereo Grundig Radio, I recovered a pair of SE OT (used with one ELL80 but fine for a pair of EL95) with Speakers and PT with around 2.18A current for filaments

My idea is to use this components for a small power Stereo SE Guitar amp with different channels (one 5F2A ond one 5C1 - both with some mod)

On the 5C1 (6ak5 tube as V1 and EL95 as Power Tube), I would like to use a TS (may be a James), to do that I can use a CF or a SF

(https://i.imgur.com/81Np4E9.jpg)

but I would like to try to put more 6AK5 in parallel, I've a lot of this tubes (also to have the advantage of paralleled tubes vs noise), as far as I can know using more pentodes in parallel will permit me to drive enough the Power Tube also if the TS drop the signal

the configuration that I think to use (for the single tube) is borrowed from a project I've seen in the web, as you can see plate resistor has a relatively low value as to avoid microphonic effect on the tube, so less output signal

(https://i.imgur.com/IatpSrK.jpg)

My question is .... Two or Three tubes in parallel to be able to use the TS without excessive Signal Loss ?


(https://i.imgur.com/ZqnPRZp.jpg)

--

For the same reasons I've think also to use 2 tubes (2 x 6N2P = 4 triodes) on the 5F2A putting the triodes of each tube in parallel

Have you councils / warnings for me ?

Many thanks

Franco


p.s.: I've a lot of 6AK5 - 5654 tubes and a good quantity of 6N2P tubes

Title: Re: Paralleled V1 (6AK5) Tube + TS -- 2 or 3 Tubes must be used to drive enough TS ?
Post by: djgibson51 on September 05, 2021, 12:47:37 am

Hi Franco,

How did this project finish? I also have a lot of these tubes.

Title: Re: Paralleled V1 (6AK5) Tube + TS -- 2 or 3 Tubes must be used to drive enough TS ?
Post by: tubeswell on September 05, 2021, 01:45:31 am

Quote from: djgibson51 on September 05, 2021, 12:47:37 am

... I also have a lot of these tubes.

Use one for a triode-connected CF to drive the TS

Title: Re: Paralleled V1 (6AK5) Tube + TS -- 2 or 3 Tubes must be used to drive enough TS ?
Post by: kagliostro on September 05, 2021, 02:07:09 am

Hi friends

I finished a lot of projects (big and small) and I'm going on with some others, but all Is about my house and my son's house


My laboratory Is full (letterally) and I enter there not easily, the more my healt Is not so good and for this reason all Is going slowly


I have more than a project ready to reach the bench, but the bench Is covered with materials to be used on the setting of the laboratory at the house of my son


Franco