UGS Power : it's U.P.

[Alettagla]

PCB's fdor UGS-power

Hello is there anyone out there that has some unused boards available for this amp or knows where to buy them?

Thanks in advance
Regards René

 

[GlouBou]

Hello,

Ask this on Travail de Groupe - DIY

Perhaps someone have this... Also you can use GERBER files on this forum too.

 

[nar]

Did anyone played a bit more with SE bias value ?
Cheef, which are the final conclusions ? Did 1A SE bias added helped in some way, or is it just troublesome ?

Best,

nAr

 

[sbear]

BS170 in diff protection circuit keeps blowing

Hi everyone. A couple of years ago I built some amps similar to Chef's U.P. in the first post which included the diff protection circuit. The amps have been great so far, except for one problem: the BS170 after the "B1" opamp segment in the protection circuit keeps blowing randomly. I have attached a screenshot of the schematic with the culprit circled in red for clarification.

I have built several channels using this protection circuit and they have all blown this FET. It became so much of a hassle to keep replacing the FET that I disabled the protection circuit on all the amps and have been using them without any offset protection for about a year! (fingers crossed. . .)

Anyway, the circuit works fine, but at random times when turning on the amps, this FET will blow. Sometimes one fet will last a month or more after I'd
d replace it. Sometimes it'd blow as soon as I'd replace it. The one constant is that it would always blow when turning on the amp from standby.

Anybody else have this problem? Any ideas?

Thanks.

Scott

 

[Zen Mod]

look in datasheet what's max allowed Ugs , then put smaller than that zenner diode between S and G

say 9V1 will be fine

 

[sbear]

Zen Mod, I assume you meant Vgs, not Ugs? I guess I didn't look at the datasheet hard enough. I didn't even think to look at Vgs. Saw that Vds was 60V and just assumed that over voltage wasn't the issue.

I'll try your suggestion or try to find a replacement with a higher Vgs rating.

Thanks.

Scott

 

[Zen Mod]

U is V , at least in my book

 

[khaho]

Zen Mod, I assume you meant Vgs, not Ugs? I guess I didn't look at the datasheet hard enough. I didn't even think to look at Vgs. Saw that Vds was 60V and just assumed that over voltage wasn't the issue.

I'll try your suggestion or try to find a replacement with a higher Vgs rating.

Thanks.

Scott

BS270 maybe helps, doubles the max Vgs.

 

[Zen Mod]

no need for that , if you protect mosfet's gate with zenner

 

[Junie]

Anyone got a spare complete PCB's, like the one posted here: http://www.diyaudio.com/forums/swap-meet/219057-fs-up-amplifier-boards.html

 

[johnyM]

Is there a big difference in any way using 0.25W resistor instead of 0.6W for UGS amp. Can I use 0.25W resistors for UGS.

 

[Zen Mod]

depends in which position

I presume that for at least 90% of positions you can use them , but without thorough analysis I can't confirm

gimme exact schm you're going to use , then we'll see

 

[johnyM]

depends in which position

I presume that for at least 90% of positions you can use them , but without thorough analysis I can't confirm

gimme exact schm you're going to use , then we'll see

Thanks Zen.

 

[Zen Mod]

from first/fast glance , all of them can be 250mW , except those in source resistors groups

they need to be what's written in parts list

 

[CeeVee]

Hi,

This will be helpfull guys

 

[Zen Mod]

C

didn't forgot ya , life is just messy lately

 

[CeeVee]

I guessed as much

 

[Zen Mod]

in fact , I'm ZM

that means - my life is always like that

 

[CeeVee]

...Mine is getting crazier by the day...i thought we should get wise with age and learn to enjoy life......must have taken the wrong turn in the road somewhere....

 

[Zen Mod]

Bugs Bunny - Albuquerque - YouTube