bosoz buzzing problem

[cowanrg]

oh ok.

ill do that anyways, but its not my problem. i completely disconnected the input section of the preamp (volume control, input selector and rca's) and fully isolated the output section of RCA's. i tested them with a meter and they were isolated from the case. however, problem still existed.

however, the good news is that im now getting smoke! i dont know which component was smoking, but it appeared to be one of the fets. i turned it off, turned off the soldering iron, turned off the stereo, turned off the lights and shut the door. unless i come across something revolutionary, im not messing with that piece of **** anymore for awhile.

[jh6you]

Originally posted by cowanrg

how can there be this many problems with such a simple circuit???

If you want to create problems and blame it . . .
The simplicity of circuit does not matter . . .
Good luck . . .


Regards, jH

[steenoe]

If you want to create problems and blame it . . .

Come on, JH. What is the purpose of a post like that? I cant imagine that it will be helpfull? Sorry. Well, I did pull out your grounding scheme again, and did give you the credit for it. How about you lend a helping hand here?

Steen

[cowanrg]

jh6you,

thanks for the advice. i tried what you suggested and it worked!

[jh6you]

O . . . my lousy post . . .


After work, will come back with a better writing.

Regards, jH

[cowanrg]

Originally posted by jh6you

O . . . my lousy post . . .


After work, will come back with a better writing.

Regards, jH

not a problem.

im just not having the best day. this whole project has been nothing but a problem from the first day. everything that could go wrong has.

[jh6you]

Originally posted by cowanrg

if i turn the amp on, wait until the buzz thing goes away, then turn it off and back on really quick, it doesnt happen again. so, its like it only happens when its "charging". thats just an explaination of how it feels, not a techincal explaination of what i think is happening.

Mine was the same as yours when power amp was always on.
Therefore, to avoid the on/off noise from BOSOZ, I did turn on BOSOZ first and later turned on the power amp. And, I did turn off the power amp first and later turned off the pre. This was my rule I followed up.

But, the problem was coming from my wife and sons. They did not keep this rule. So, "onZZZZzzzz . . . " "offZZZZzzz . . . "

I think this is due to the charging and discharging of the output coupling caps. So far, I know two solutions. One is installing the delayed-on/quick-off relay. Another is my method.

My method . . . ?

I am living in an apartment. I do not need very loud music. Merely loud enough to make my neighbors to hover beteen "should I call this guy or not?" . . . So, I do not need high gain from my BOSOZ. I lower the gain (almost unity) by reducing impedence of my balanced output volume attenuator. Meanwhile, this helps very much to speed up the charging and discharging time of the output caps. It gives me no on/off noise.


My BOSOZ has unusual output form . . .


Regards, jH

[cowanrg]

ok. more reading!

i did more reasearch and it seems its a bit of a problem that the bosoz has some turn on/off thump. it just seems im getting a buzzing instead. the buzzing doesnt happen if i turn it on and off quickly. so, when the caps are charged, there is no buzz.

as far as the smoking of the fet, who knows. ill deal with that later. so, to fix the issue, i think ill go with the velleman kit k4700. ive seen many people use this and it seems to work. however, it seems like its ONLY for 220? can anyone confirm that, or suggest something comparable that can work off 120?

thanks.

[fcel]

I have ordered Vellerman kit from the same place that sells the BOSOZ boards - can't remember the company now but it's in US. It comes in 120v even though the ad says 220v.

[cowanrg]

hum. could you possibly dig up a link at all?

did you end up using the elektor soft start too, or just the velleman kit?