Burning Amp BA-3b (Balanced)

[Melon Head]

ya can bet that Papa did

Probably also do a comparison of laterals vs verticals.

800VA transformer per channel

 

[Melon Head]

I am really most interested in the circlotron output though.

 

[buzzforb]

I will be making up balanced BA3 FE connected to BA1 output, BA2 output, and circlotron output.

The plan is to put the front end in it's own case with shunt regulator (most likely a Salas shunt) and the output stage in another case with CRC power supply.

For the BBA3-BA1 output, I am thinking +/- 22V supplies and 5A per output phase for a total of 10A drawn from the power supply. So it is definitely going to be monoblocks.
Has anyone tried this yet?

Salas shunt has a tendency to focus an amp and create a very dark background. While i like the absolute silence, it can take away from the bloom a lot of people like in amps. Since it will be on just the FE, it is feasible that some of this blloom can be recaptured in output, especially BA1 version. Just thought you might like to know.

 

[buzzforb]

I am really most interested in the circlotron output though.

isnt balanced BA1 output sort of a circlotron type circuit without the dual supplies?

 

[Melon Head]

Here it is.

 

[Melon Head]

isnt balanced BA1 output sort of a circlotron type circuit without the dual supplies?

No. Circlotron looks different
I have been tempted to give it away, but I have not built it yet.

 

[Melon Head]

Circlotron can do magical push pull from all N channel mosfet.
It doesn't run out of current.

 

[Melon Head]

Salas shunt has a tendency to focus an amp and create a very dark background. While i like the absolute silence, it can take away from the bloom a lot of people like in amps. Since it will be on just the FE, it is feasible that some of this blloom can be recaptured in output, especially BA1 version. Just thought you might like to know.

Thanks.

 

[Melon Head]

Nelson is definitely saving the best till last.

 

[Zen Mod]

......
800VA transformer per channel

naah

that's for sissies

real man must use buckets for support of their xformers

 

[Zen Mod]

btw.

Buzz is definitely going in same Golden Ear Club with my man Generg

 

[Melon Head]

naah

that's for sissies

real man must use buckets for support of their xformers

Are they yours?

 

[buzzforb]

btw.

Buzz is definitely going in same Golden Ear Club with my man Generg

Working with power tools all day has really shaped my listening abilities. I am proud to be in club with Generg, if for no other reason than i know there will be lots of suds!

 

[Melon Head]

naah

that's for sissies

real man must use buckets for support of their xformers

Yeah you are right. 800VA is not enough.
Either 1kVA or 1.5kVA per channel.

 

[Zen Mod]

Are they yours?

nope

see that Gentle Man on third pic ?

 

[lhquam]

Negative Feedback Heresy?

Is is heresy to consider 3 stage negative feedback in the PASS Forum?

I did a SPICE simulation of a low power F5 (using BA-3 output FETs) driving a BA-2 and negative feedback from the BA-2 output? Simulations look excellent, but it might be too much like a "conventional" production amplifier.

Has anyone sonically compared such an amplifier with the BA-3/BA-2 or equivalent balanced versions?

 

[Melon Head]

You could use a switch to switch it in and out if you wanted to hear it

 

[lhquam]

You could switch it in and out if you wanted to hear it

I am not sure how I could switch the negative feedback in and out without lots of poles on the switche. The biasing and JFET stage gains are totally different. I would have to look carefully to see if I could get an F5 to operate well in the BA-3 fashion with no global feedback.

I welcome your suggestions of how to do it.

 

[Melon Head]

Just use a 2 pole switch or even a regular switch.
You don't necessarily need 2 wires at the output. You can just have one wire linking the ouput of BA2 to the dual feedback of F5. Then just switch it open and close.

 

[Melon Head]

You have a PM