Help - Poor results from Cathode Bypass Mod - user error!

drewh1 · 7030

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Offline drewh1

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I installed Mundorf 47 uF's across as described in the thread on this mod.  Soldered caps from t6 - t16 and t10 - t20 as described.  Removed the wires to K on the PCB.

My overall volume seems down about 6 db and my bass response is significantly decreased.  Everything else seems fine. Balance is ok and instruments are where they are supposed to be in soundfield.

Any ideas?

« Last Edit: October 28, 2015, 03:12:27 PM by drewh1 »

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Offline Paul Birkeland

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Reply #1 on: October 24, 2015, 09:15:31 AM
How are the voltages? 

If the voltages are OK, let the amp run overnight, then recheck.

Spending more money on capacitors often times does not improve the performance of an amplifier. 

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline drewh1

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Reply #2 on: October 24, 2015, 11:25:46 AM
Ok - I hear you.  All the other mods I did seemed to make improvements, Should have left great enough alone  :D   Live and learn.

Assuming the voltages are ok, do you think putting the wires to k back in would make a difference?

J-River on Custom built Music Server in Silverstone Case
Ayre QB-9 USB DAC
Kaiju
Stereoumour
Diy Cotton wrapped wire interconnects and speaker cab!es
Green Mountain Audio EOS HDx speakers
Crack with Beyerdynamic T1
Shunyata Diamond Back Power Cable
DIY Sub with Seas L26Roy Driver


Offline drewh1

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Reply #3 on: October 24, 2015, 12:14:39 PM
All voltages check out within 10 or 15%.

The only thing that seemed off was T2 is 240 and T14 is 223.  I don't remember any variations from my original voltage checks.



J-River on Custom built Music Server in Silverstone Case
Ayre QB-9 USB DAC
Kaiju
Stereoumour
Diy Cotton wrapped wire interconnects and speaker cab!es
Green Mountain Audio EOS HDx speakers
Crack with Beyerdynamic T1
Shunyata Diamond Back Power Cable
DIY Sub with Seas L26Roy Driver


Offline Paul Birkeland

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Reply #4 on: October 24, 2015, 12:29:14 PM
Assuming the voltages are ok, do you think putting the wires to k back in would make a difference?
That would put the other cathode bypass caps back into the circuit.  It might help, but I'd wait a few days on that.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline drewh1

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Reply #5 on: October 24, 2015, 12:36:57 PM
Thanks for your help Paul - I did figure out the volume issue, it was a wrong setting on J-River that popped up when the computer reset, set to internal volume and started up at 75% of full volume. 

Jury is still out on the bass but i'll give it a few days to settle in.  Mostly things sound really good. I apologize for wasting your time - should have spent more time trouble shooting.
« Last Edit: October 24, 2015, 03:55:01 PM by drewh1 »

J-River on Custom built Music Server in Silverstone Case
Ayre QB-9 USB DAC
Kaiju
Stereoumour
Diy Cotton wrapped wire interconnects and speaker cab!es
Green Mountain Audio EOS HDx speakers
Crack with Beyerdynamic T1
Shunyata Diamond Back Power Cable
DIY Sub with Seas L26Roy Driver