How about BK power amps?

[PF Sound]

So the recap is happening sooner than later...found a guy in Long Island who has worked on these for a long time, knows them inside and out...

will let you know how it goes...

Steve @ Stargate? Yes, he'll fix it.

I've had a Ref-7250 & 200.5 .........love em both. JMO, & that of others, that B&K is great bang for the buck when going separates. Yes they run "hot", but I just keep mine well ventilated, ie not cramped up in a small rack with other components.

 

[Bkphoto]

Yep, he has it now...

 

[Nashou66]

B&K factory was right up the street from me . When they closed someone got all thier left over parts inventory and unfinished
amps, cases PCB boards, transformers schematics etc. This was before I really got into repairing equipment. Reading this thread
has got me wishing i made an offer for everything. I went to look at it and I could have easily
got about 5-8 amps out of all the stuff there.

And there was more of the more modern AV preamps unfinished but too many IC chips
all over the place in boxes to even entertain rebuilding one of those.

Nashou

 

[crazy eights]

i have the reference 2220 power amp it's been playing pretty loud for the last six hours (about 80- 90 dB) powering a pair of AR9LS, i think it sounds great and it's barely warm to the touch

 

[PF Sound]

B&K factory was right up the street from me . When they closed someone got all thier left over parts inventory and unfinished
amps, cases PCB boards, transformers schematics etc. This was before I really got into repairing equipment. Reading this thread
has got me wishing i made an offer for everything. I went to look at it and I could have easily
got about 5-8 amps out of all the stuff there.

And there was more of the more modern AV preamps unfinished but too many IC chips
all over the place in boxes to even entertain rebuilding one of those.

Nashou

Man, that's too bad because their pre-amps/receivers have a fairly common fault in that an eeprom fails & can't be recovered, only replaced.........& you can't get them anymore, which turns a once-expensive pre-amp into a brick.

 

[Nashou66]

Man, that's too bad because their pre-amps/receivers have a fairly common fault in that an eeprom fails & can't be recovered, only replaced.........& you can't get them anymore, which turns a once-expensive pre-amp into a brick.

Man, that's too bad because their pre-amps/receivers have a fairly common fault in that an eeprom fails & can't be recovered, only replaced.........& you can't get them anymore, which turns a once-expensive pre-amp into a brick.

Crap!!!!

I knew I should have got the lot !!!

Nashou

 

[gentlejax]

get the big brother to the 140

 

[twiiii]

We sold Hafler, too and we never had the issues we had with B&K. Haflers sounded nicer, too. A friend used his to drive Mac speakers and the sound great. Easily as good as the direct coupled MC 7200. Which was my favorite at the time.

 

[Pio1980]

We sold Hafler, too and we never had the issues we had with B&K. Haflers sounded nicer, too. A friend used his to drive Mac speakers and the sound great. Easily as good as the direct coupled MC 7200. Which was my favorite at the time.

Which Hafler amp was that?

 

[swbeebe]

I was wondering if anyone knows the proper bias setting for the ST3030?
I found the following, but this model is not listed....

1. Plug the amplifier into a variac. Monitor the (-) negative rail of each channel by removing
the fuse and placing a current meter across the fuse clips.
2. Connect an 8 Ω load to each channel. Supply an input signal of 100 mV RMS @ 20 Khz.
3. Slowly turn the variac up to operating voltage while monitoring the rails for excessive
current draw. The meters should not read more than 400 mA DC. If one or both read
more than 400 mA, turn the bias pots (P2) to minimum and retry.
4. Set bias of the amplifier by adjusting the bias pot (P2) mounted on the solder side of the
board to achieve a reading of 200 mA on each channel for models ST 140, ST 140M,
ST 202, and ST 202+.
The bias for the Pro 600, EX 442 and M 200 amplifiers is 250 mA.
Setting the bias higher than stated only causes the amplifier to run hotter and burn out
faster. It does nothing for the sound quality of the amplifier.
5. Set the DC out of the amplifier by monitoring across the outputs. Adjust the DC pot (P1)
for 0 VDC ± 5 mVDC.

 

[PF Sound]

I was wondering if anyone knows the proper bias setting for the ST3030?
I found the following, but this model is not listed....

1. Plug the amplifier into a variac. Monitor the (-) negative rail of each channel by removing
the fuse and placing a current meter across the fuse clips.
2. Connect an 8 Ω load to each channel. Supply an input signal of 100 mV RMS @ 20 Khz.
3. Slowly turn the variac up to operating voltage while monitoring the rails for excessive
current draw. The meters should not read more than 400 mA DC. If one or both read
more than 400 mA, turn the bias pots (P2) to minimum and retry.
4. Set bias of the amplifier by adjusting the bias pot (P2) mounted on the solder side of the
board to achieve a reading of 200 mA on each channel for models ST 140, ST 140M,
ST 202, and ST 202+.
The bias for the Pro 600, EX 442 and M 200 amplifiers is 250 mA.
Setting the bias higher than stated only causes the amplifier to run hotter and burn out
faster. It does nothing for the sound quality of the amplifier.
5. Set the DC out of the amplifier by monitoring across the outputs. Adjust the DC pot (P1)
for 0 VDC ± 5 mVDC.

The SM for the 3030 series II is available on Hifiengine. I don't know which model you have but that's a start.

 

[swbeebe]

The SM for the 3030 series II is available on Hifiengine. I don't know which model you have but that's a start.

It doesn't include the bias levels. It's a series 1, but they are fairly close. Enough that I was able to complete the repair minus the bias adjustment.

 

[PF Sound]

D

It doesn't include the bias levels. It's a series 1, but they are fairly close. Enough that I was able to complete the repair minus the bias adjustment.

Did you have to replace the bias trimmers? If not, what were the bias readings after the repair? They MAY be somewhat close to the recommended setting if they hadn't been touched. It seems that it will likely be either 200mA or 250mA, based on other models.

 

[swbeebe]

I set it to 200mA. They were turned all the way up and drawing about 1.5A.

 

[ghamilton]

I had the ST-202 and it sounded great. Man did it run hot! The heat sinks sticking out the back really got hot. My nephew has the amp now and it is still going. Does anyone know where I can download a service manual for it?