And the journey begins...

Pulpmillguy said:
OK, Mouser ships from Czech Republic...got the stuff today!

Now I have powered up the backplanes only and am getting about 0,9 VDC on the output...is this normal and it is OK to proceed with installing the pre-drivers or is there something that I need to investigate first?

No smoke or funny smells so I am hoping that everything is OK so far...please advise.
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Put your 10Ks back in and remeasure results...
 
Well...got like 80 VDC on the buss (on the DBT) with the backplanes powered...nothing fried so decided to try it in bypass...now I have +/-103,2 VDC which is much better. Got the pre-drivers and 2 rows of output transistors installed, bias running 0,36VDC on both channels. 0 VDC on the output, +15,2/-15,6 VDC on the control board, things are looking good. Batteries dead on both meters, time to call it a night and think about other things.

Dayum.png
 
MarkWComer said:
Robbie: don’t feel bad- I once ordered the whole kit except for the output transistors, got them separately from Mouser. I could have saved some time.

BTW- download the Audacity application on yer laptop- it makes a convenient frequency generator to check your DC protection circuit and calibrate your display LEDs.
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That one meter I have is a handheld signal generator/scope, I'll use that for checking Don's board.
 
Back in the saddle again...
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In reality I shouldn't have it hooked up to the JBLs but I just had to listen to it...and it sounds FANTASTIC, thank you Joe for the amazing design and kits! I checked the DC offset and it was zero on the left channel and 0,0005 on the right...I'd say that was acceptable. Bias is set to 0,36 VDC on both channels, just need to get one little issue fixed.

Now for the bad part...the DC protection board doesn't work...I hooked up signal generator and got down to 1 Hz and it didn't trip...need to talk to Don about this. It was doing the same thing when I had it hooked up in the original PL but it was only acting up on one channel, now it is doing it on both.

But at least the biggest mountain has been scaled...

I want to thank all of the guys that gave me advice (and grief) and helped out along the way, couldn't have done it without you. It was a wonderful journey and I must be sadistic but I want to do it again!!!
 
Black face with blue lights looks BEAUTIFUL!

Yeah- that first listen is a surprise, isn’t it? My first was a 400 S2, first play was Joy Division’s “Heart and Soul,” the opening bass line was incredible- deep, tight, and well controlled. I expected to hear mud.
 
MarkWComer said:
Black face with blue lights looks BEAUTIFUL!

Yeah- that first listen is a surprise, isn’t it? My first was a 400 S2, first play was Joy Division’s “Heart and Soul,” the opening bass line was incredible- deep, tight, and well controlled. I expected to hear mud.
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Oh yeah...that front panel looks bad-ass...

And it was ZZ Top LaGrange...that was the first song I ever heard on a set of L200s
 
Now listen to some well engineered electronica like Shpongle...that'll open your ears..
 
Allright guys...put on your thinking caps.

In terms of signal/noise and any background hum, there isn't anything but my damn transformer buzzes...a low hum but definitely something there...any ideas of why and what I can do to get rid of it?
 
Pulpmillguy said:
Allright guys...put on your thinking caps.

In terms of signal/noise and any background hum, there isn't anything but my damn transformer buzzes...a low hum but definitely something there...any ideas of why and what I can do to get rid of it?
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What about engineering the AC runs out from passing through all Joe's new bits?

I've considered trying to put the thermal cut out switch(s) outside or maybe run the rectified DC to the cut outs....

Thoughts ?
 
Mohawk said:
What about engineering the AC runs out from passing through all Joe's new bits?

I've considered trying to put the thermal cut out switch(s) outside or maybe run the rectified DC to the cut outs....

Thoughts ?
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It has nothing to do with the wiring...the transformer was making the noise when I was commissioning just the power supply so I know there isn't "crosstalk" between the AC wiring and all the new bits and pieces.

And to be honest, I don't remember the transformer being noisy before I WOPL'd it...makes me wonder if I did something to the core when I disassembled it to do the bolt isolation.
 
Make sure you have the all transformer mounting bolts tight to hold the laminations tightly together.

I have observed the laminations become loose due to handling and can vibrate at 60Hz if not secured after mounting.

I would also try removing the spacers between the cap cradle and housing.
 
Hexis22 said:
Make sure you have the all transformer mounting bolts tight to hold the laminations tightly together.

I have observed the laminations become loose due to handling and can vibrate at 60Hz if not secured after mounting.

I would also try removing the spacers between the cap cradle and housing.
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so you are OK with having the aluminum end bell in contact with the chassis? (and it's 50 Hz over here but probably no difference :cool:)
 
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