Mnats rev J stereo 1176 with Balancing board and adjustable PSU build

Hi guys,

This is where the OPA2604 is mentioned as replacement for the NE5532.

http://www.diyaudio.com/forums/solid-state/898-upgrade-ne5532.html

Would like to know your thoughts.

Regards

Spence.

Spencerleehorton said:

..what i meant was one Mnats G1176 pcb

Click to expand...

It might be helpful to know what pcb you are working on (G1176 is a Gyraf board, MNats offers different 1176 revisions).

R89 (200R) is getting very hot

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In the original build the 220R R89 has 5V across, dissipating 0.11W, if R87 was 1K1 for real. You might have fitted tiny wattage or wrong resistor values if this resistor got hot. Anyway both are not needed/contraproductive with your separate PSU in front.

..and should i also remove C23?

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Depends on distance between your PSU C7 and your 1176x boards. I'd probably keep them.

This is where the OPA2604 is mentioned as replacement for the NE5532.
http://www.diyaudio.com/forums/solid-state/898-upgrade-ne5532.html
Would like to know your thoughts.

Click to expand...

Without context you can not successfully swap parts. No idea why this guy wants to downgrade to a lesser suitable part for this task.

HI Guys,

right my pcbs are Mnats 1176 Rev J.
I have taken out both R87 and R89 and no smoke now and ive left in C23.
Should i use OPA2604 or use NE5532? i'm assuming the NE5532 is much better for the 1176?
Also have checked all voltages on IC's and all seem to be within what is needed.
I am now getting correct voltages in on both left and right channel, 30v and -10v.
only wrong voltages are on Q14 which i'm getting 0.784v on left channel and 7.75v on right channel?
On schematic it says i should be getting 17.75v on the collector?
all other transistors seem to check out so far.

any more ideas on how i should proceed and get R16 working correctly?

regards

Spence.

Have updated the thread title to be accurate now, capacitor was wrong and making opa2604 oscillate, still check through board, seems to be a problem somewhere at the ratio board.
Will update soon.

Spence.

Little update, one channel is now working now after a few wrong resistors and attack and release pot wired wrong!, getting compression now, just need to get other channel playing ball.
Once both sorted and setup gonna install the stereo link board.
Photos will follow soon.

Regards

Spence.

Have got both channels working now, but hum on left channel?
Gonna try to move toroidal to see if it the problem.
Still haven't done stereo link board.
Have used THAT1646 on balancing board and they seem to sound better than DRV134, less noisy.
Haven't tested these against the SSM2142 yet.
Will update once got everything working correctly.

Regards

Spence.