Author Topic: low volume on ehx ic big muff  (Read 376 times)

whomeno

low volume on ehx ic big muff
« on: September 01, 2020, 07:38:26 AM »
built form here http://tagboardeffects.blogspot.com/2013/12/ehx-ic-big-muff-v5-78.html
I used a tl071 for ic2 replaced the 820k with 1m as listed
when I engage the pedal the volume is low. you have to turn the volume up to 7 to get the same volume as when off. all resistors are carbon film 5%. last pedal useing them going to metal film 1%.
voltages are at 9 volt
4558
1  4.22
2  4.23
3  4.18
4  0
5  4.2
6   4.2
7   4.2
8  8.49

TL071
1  0.14
2  4.2
3  4.0
4  0
5  0.14
6  4.2
7  8.49
8   0








Gear as of now
Gibson 2017 Les Paul Tribute T
Marshall DSL40cr
Peavey valveking2

antonis

Re: low volume on ehx ic big muff
« Reply #1 on: September 01, 2020, 07:52:31 AM »
Is there any volume difference between Tone ON & BYPASS..??
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

whomeno

Re: low volume on ehx ic big muff
« Reply #2 on: September 01, 2020, 09:05:04 AM »
yes
Gear as of now
Gibson 2017 Les Paul Tribute T
Marshall DSL40cr
Peavey valveking2

antonis

Re: low volume on ehx ic big muff
« Reply #3 on: September 01, 2020, 02:05:28 PM »
It shouldn't be.. :icon_wink:

There should be a resistor of about 150k in series with signal when Tonestack bypassed..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

whomeno

Re: low volume on ehx ic big muff
« Reply #4 on: September 02, 2020, 09:07:35 PM »
ok rebuilt board with all metal film 1% resistors. no volume change with the tone bypass switch. but the low volume still remains. any more ideas
Thanks
Gear as of now
Gibson 2017 Les Paul Tribute T
Marshall DSL40cr
Peavey valveking2

whomeno

Re: low volume on ehx ic big muff
« Reply #5 on: September 02, 2020, 09:10:02 PM »
the schematic used was from Analogguru's schematic
Gear as of now
Gibson 2017 Les Paul Tribute T
Marshall DSL40cr
Peavey valveking2

Quackzed

Re: low volume on ehx ic big muff
« Reply #6 on: September 02, 2020, 09:35:45 PM »
you could try an audio probe at pin 6 (output) of ic2 audio probe is just a guitar cable with one side to amp and the other sides ground lead connected  to circuit ground (alligator clip or soldered) and the hot lead connected to one side of aa cap and the other side to different 'test' points. basically see at what point in the circuit the level becomes low, then you can check that area to figure out why the signal is dropping...
looking at the schematic you could also just desolder vol3 wire (vol1 is ground it appears)  and use that as a 'probe' that wire is goint to the out jack so if you touch it to ic2 pin6 it should tell you if the vol drop is happening at the tone control section...
nothing says forever like a solid block of liquid nails!!!

whomeno

Re: low volume on ehx ic big muff
« Reply #7 on: September 02, 2020, 10:14:30 PM »
ok so it is in the tone control section. pin 6 has good volume
Gear as of now
Gibson 2017 Les Paul Tribute T
Marshall DSL40cr
Peavey valveking2

whomeno

Re: low volume on ehx ic big muff
« Reply #8 on: September 02, 2020, 10:33:27 PM »
ok got good signal to vol lug 3. it calls for a log 100k . to get the same volume when pedal is disengaged vol has to be at 10
it just seem right but maybe it is
Gear as of now
Gibson 2017 Les Paul Tribute T
Marshall DSL40cr
Peavey valveking2

antonis

Re: low volume on ehx ic big muff
« Reply #9 on: September 03, 2020, 04:59:18 AM »
At ten o'clock it's more than fine.. :icon_wink:

Volume level depends on last stage output impedance & Vol pot (setting & value) & next stage input impedance..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

whomeno

Re: low volume on ehx ic big muff
« Reply #10 on: September 03, 2020, 07:54:31 AM »
done with this one
Gear as of now
Gibson 2017 Les Paul Tribute T
Marshall DSL40cr
Peavey valveking2