The BA-3 as preamp build guide

[6L6]

Burning Amplifier Gain Stage for BA-3 – diyAudio Store

 

[codyt]

I’ve been thinking of giving the BA-3 as preamp a whirl, but would like to do it with the parts and chassis I have on hand. What I’m thinking is fitting the preamp board into a smallish galaxy chassis (currently housing a B1) and, for now, getting my power from two meanwell 24v desktop supplies. Might do an RC round in the chassis too. If I decide to stick with it, would then build a proper external supply. Any advice/warnings concerning this approach?

 

[McQuaide]

I ran my Pearl 2 like that for years, as long as it's getting a clean +-24V it shouldn't matter how you do it.

 

[codyt]

I ran my Pearl 2 like that for years, as long as it's getting a clean +-24V it shouldn't matter how you do it.

Nice! Out of curiosity, did you see an improvement with Pearl when you switched to a linear supply?

 

[McQuaide]

I went from 2 industrial regulated supplies to the stock one, so theoretically it was a step down. I didn't notice a difference, as the Pearl does its own regulation and filtering.

 

[codyt]

I went from 2 industrial regulated supplies to the stock one, so theoretically it was a step down. I didn't notice a difference, as the Pearl does its own regulation and filtering.

Yeah, that’s a good point.

 

[codyt]

Anybody know if a trusted source for 2SJ313‘s and 2SK2013’s? I’ve seen a few listings on eBay, but unfamiliar with the sellers

 

[Hikari1]

Anybody know if a trusted source for 2SJ313‘s and 2SK2013’s? I’ve seen a few listings on eBay, but unfamiliar with the sellers

DIYAudio user "NicMac" used to sell them. But I think his supply is gone now.

I would just use Fairchilds.

 

[Dennis Hui]

You might try Prakit:

FS: TOS 2SK2013/2SJ313

The Fairchilds are good and readily available.

 

[codyt]

Thanks for the suggestions! Following up, but guessing it’ll be the Fairchild’s for me.

 

[Russellc]

Thanks for the suggestions! Following up, but guessing it’ll be the Fairchild’s for me.

Fairchilds are fine but require a different pot value...

Russellc

 

[Dennis Hui]

Yes, 1K for Fairchilds.

 

[JeffYoung]

I have a bunch of the Toshibas, but I haven't matched them yet. I'm pretty sure @prakit still has them for sale....

 

[Tomcat1969]

Hey guys. I'm gathering parts for this build. What is the Va rating for the tx.

 

[McQuaide]

Hey guys. I'm gathering parts for this build. What is the Va rating for the tx.

The first post of this thread has it.

Edit - I don't see the VA rating there but the BOM I have specifies 50VA.

 

[Tomcat1969]

Thanks very much. I've been reading but seemed to have missed it. Many thanks.

Billy

 

[6L6]

Anything between 30-50VA will be more than sufficient.

 

[Manolo47]

How about 400VA, difference is noticeable! Bigger soundstage and deeper bass.

 

[McQuaide]

How about 400VA, difference is noticeable! Bigger soundstage and deeper bass.

Are you referring to the BA-3 amplifier? This is for the BA-3 front-end preamp.

 

[Manolo47]

yeap! Ba-3 line stage