Author Topic: Mudbunny (etched) trouble. Low volume!!  (Read 1730 times)

TheCobbenator

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Mudbunny (etched) trouble. Low volume!!
« on: September 02, 2011, 12:40:02 PM »
Hey everybody.  So I have run into a wall with my etched mudbunny Violet Ram's Head.  All the controls seem to be working correctly (including the presence mod,) but it's just SUPER quiet. With the sustain and volume pots maxed, it's maybe 1/4 as loud as bypassed. The tone seems a little too fizzy, but IDK if that's maybe because it's just so quiet and the circuit is cranked that it sounds weird.

I used the BC549B from Tayda, and will probably swap them out for the original 2n5088s for more gain once I get it working. 

I don't think I subbed anything except the suggested values to make the mid sweep more dramatic. I can't find any solder bridges, and everything looks right.

Any things particular this sounds like it could be?

jkokura

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Re: Mudbunny (etched) trouble. Low volume!!
« Reply #1 on: September 02, 2011, 01:32:31 PM »
Generally, if the effect seems to be working correctly but there is low volume the problem can be traced back to an incorrect part close to the end of the circuit. I had a similar problem with a tubescreamer I built where I had installed a 100K resistor where it should have been a 100R resistor.

Recheck the values of your parts towards the end of your circuit.

You can also use an audio probe to trace backwards in the circuit to find the problem. Start at the output on the board and then go backwards until you get a volume kick. The part where the volume drops is obviously the problem.

Jacob
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mgwhit

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Re: Mudbunny (etched) trouble. Low volume!!
« Reply #2 on: September 02, 2011, 01:38:40 PM »
You should definitely getting much more volume.  I built one to VRH specs and I almost never push the Volume knob up to 12:00.

Try swapping the orientation of your transistors.  BC549's look like they're CBE, and 2n5088's look like they're EBC.  Check the project PDF.

pietro_moog

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Re: Mudbunny (etched) trouble. Low volume!!
« Reply #3 on: September 02, 2011, 01:48:25 PM »
i had the same problem once. you have them reversed. just reverse them.
a big muff is NOT quiet.
beware of the new volume. close all pots before.

TheCobbenator

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Re: Mudbunny (etched) trouble. Low volume!!
« Reply #4 on: September 02, 2011, 03:23:33 PM »
Yeah. Well I followed the pinout(bc549) of the etched layout in the mudbunny PDF . So I know I didn't install the trannies backwards. I'm thinking it probably was just a wrong resistor near the end or something similar like Jacob said. And thanks fr the heads up, but yeah -- it should def be insanely loud! I'll check these out when I can get a chance and let you know if I fix it! <fingers crossed>

Thanks, gents!

-Justin

bigmufffuzzwizz

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Re: Mudbunny (etched) trouble. Low volume!!
« Reply #5 on: September 02, 2011, 06:36:06 PM »
That does sound characteristic of a backwards transistor. If all the parts check out correctly, try socketing the trannys and trying different configurations. I've never damaged general transistors like these by inserting wrong direction.
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TheCobbenator

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Re: Mudbunny (etched) trouble. Low volume!!
« Reply #6 on: November 12, 2011, 05:23:08 PM »
Okay... back from the dead.

I removed the BC549s, socketed the transistors and put in 2n5088s in the opposite direction of the layout... then one by one switched them around in direction. None of these changes made any difference to the output.  IDK what to do at this point. Right now it's back in my pile of dead circuits (not too big of a pile)

any suggestions?

petesz

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Re: Mudbunny (etched) trouble. Low volume!!
« Reply #7 on: November 12, 2011, 06:21:48 PM »
reflow your solder joints on the pots?
this happened to me once but it was a bad solder joint on the volume control of the ruby amp i use to test my pedals..

mgwhit

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Re: Mudbunny (etched) trouble. Low volume!!
« Reply #8 on: November 13, 2011, 05:50:25 PM »
Did you ever follow jkokura's advice and check to make sure you didn't put 100K's in place of the 100R's in R5, R11 and R16?  That's and easy and common mistake and would result in really low amplification from the transistors.

If that isn't it, how about posting clear photos of the front and back of your board?