Burning Amp BA-3

[Botte]

Hi Nelson,

Yes, I ‘m using the 2sk170 and 2sj74 they are BL and the Idss is 6.89 in a cool environment out of the chassis. So they should creep up a bit with heat.

I have the 330 ohm load and 22 ohms on the drains. I’m not complaining, I didn’t want the THX sticker anyway. I’m just trying to figure out how it works. I’ll run some distortion measurements and report back.

Thanks,

 

[generg]

O.k. master,

Smarty-pant generg

 

[Variac]

For those of you who are not attending BAF, you will delighted to know that
I will be presenting the BBA-3, the balanced version.

Not to despair, I will put it online very shortly after. In the meantime,
hands-off to the usual smarty-pants who are probably already working on
this...

this is what I was referring to when I said "But we can hope for a little spin on things can't we?"
My system's balanced, so I'm MORE than delighted!!!!

 

[buzzforb]

Are we going to be able to mod it using Store boards? They tend to be a little cleaner than what I come up with.

 

[Variac]

I don't know how different they will be. So don't know if you can mod the store boards or if we'll come up with new ones.

Nelson really likes surprises , so he doesn't tell me either..

If he current store boards ca nbe modded then each board would only do one channel, so you would need 2 boards for 2 ch balanced.

 

[buzzforb]

Probably can''t be done as there will be new components that tie the two together. Just didn't know if it was known ahead of time and the boards were made with the change in mind.

 

[Variac]

Well, yeah, I'm sure some traces would need to be cut, but extra components can be used to connect the two sides probably.. ehh we'll just have to be patient- like Christmas. We'll make a new optional version if it is too complicated but that takes a while. .

 

[Backbones]

If there is to be another set of boards can I put in a request on behalf of those of us who are using Elna SilmicII. 1000uF 25V are just a little too wide for the current front end boards.
Chris

 

[Nelson Pass]

It's a simple mod to the existing board. No trace cutting.

 

[Backbones]

It's a simple mod to the existing board. No trace cutting.

Any rare or exotic components needed?

 

[buzzforb]

I would think it is just a matter of tying the sources of the input pair together. I would imagine the trick is in how you do that while maintaining the ability to play with harmonic distribution. Just guessing though, as I do not know how.

 

[Backbones]

A pair of SJ109s?

 

[buzzforb]

A75 article may have some hints, still guessing. SJ109 is unneccessary. SJ74 pair and sk170 pair are the same thing(close) if matched.

 

[buzzforb]

I believe I figured it out with the help of another thread link, but will experminent in the dark recesses of my home and wait for BA. Maybe by then, mine will literally be a BA.

 

[flg]

I think some insight might be gained in the F5 - the EUVL approach?

 

[Nelson Pass]

You'll just have to wait 120 hours....

 

[buzzforb]

Am I correct in assuming that the balanced version would maintain the no feedback concept.

 

[CanAm Man]

Saddens me to know I'm headed to the "Right Coast" of the US for business, when all of you are going to the "Left Coast" for audiophile fun and adult beverages.....

If you get the urge for good Italian food, try Frascati - SF

If you have a craving for great Pan-Asian, try The House

Two of my favorites....! You'all have a great time at BA.....

Ken

 

[Botte]

BA-3 Low gain

Hi Guy's

I did some more checking on the front end and I’m getting .5 of the input signal at the gates of the Q3 and Q4 from the input stage, I’m wondering if R5 should be a 50 ohm resistor? The math doesn't seem to work I get 2 or .5?

Thanks,

 

[buzzforb]

For anybody other than me that wants some idea of how a level shifter works.
http://www.trekinc.com/pdf/6001_Voltage_Level_Shifting.pdf