BA-3 As Preamp

[6L6]

I concur.

 

[bnorrish]

Starting to think Peter Daniels PSU board with LM317/LM337 would work well with the BA-3 as a standalone preamp. Simple, low part count like BA-3.

 

[6L6]

Good idea! Do that and finish the Pumpkin/Shunty. Compare. Contrast.

 

[vdi_nenna]

How does a designer know what value resistance to choose for a volume control?

 

[buzzforb]

 

[merlin2069er]

What kind of boards are those?

 

[PKI]

Buzz, stop sowing off! ;-)

 

[buzzforb]

my BA3 preamp.

 

[PKI]

Your super cool BA3 preamp!

 

[buzzforb]

V1.

 

[Mr. dB]

my BA3 preamp.

(1) Why are the ends of the heat sinks cut off?

(B) Nice to see that you've put the prices for some of the components on there...

 

[buzzforb]

THe heatsinks were cut off by the defined dimensions of the board. Didnt go to thetrouble of labeling the pieces, as it is a proto. ThE next version will have options for cascodes and multiple feedback points.

 

[vdi_nenna]

Bump-

How does a designer know what value resistance to choose for a volume control?

 

[6L6]

That's one of those questions that is immediately obvious to those who already know it, and completely mysterious to those who don't...

I fall in the later camp, sadly.

 

[buzzforb]

IT has a lot to do with the topology. If using standard BA3, I would use a 25K pot, like in the B1. If you are using cascoded topology, you can get away with a 50K pot. It relates to Miller effect and its interaction with the value of the pot. JFet Frontiers Pt1 and 2 by Erno Borberly explains it very well.

 

[evanc]

JFet Frontiers Pt1 and 2 by Erno Borberly explains it very well.

excellent info

 

[merlin2069er]

Where did you get boards for your ba3 pre-amp?

 

[buzzforb]

I had them made.

 

[merlin2069er]

oh, are these the same burning amp 3 boards sold here on diyaudio.com?

 

[buzzforb]

No. THere are some modifications