#0102 fault and treble pots

[Mark]

Hi

I have a Boogie SOB which I bought years ago. It has been a wonderful platform to try various amp circuits on.

It has been a Bluesmaster for some time and I thought I'd turn it into a #0102. I had only heard a D'Lite as a #0102 and I'm inclined to think at this stage the Boogie does sound different.

I've used a 250K log pot in this amp as a treble pot where as the D'Lite has a linear pot. The log pot doesn't do a whole lot till it reaches the end of it's travel where as the linear pot doesn't seem to do a whole lot over it's range. While I'm aware it is only a matter of how things are perceived, it still effects how one would use the tone controls.

This made me wonder what is the best pot to use when a the vintage Fender /CTS pot isn't available?

On to the fault, the fault appears to be in the pre-amp and it is something I haven't come up against before. There is a buzz/rattle sound on the bass notes, that is to say from low "E" to it's octave.

I have plugged into the PI stage and used a Memory Man to boost the signal and it sounded fine.

I have changed the valve and chop sticked it a little and I haven't heard a change in the buzz.

I'm wondering what is the best way to approach this problem as there is no noise when the guitar isn't played nor is there an issue on the higher notes.

The bass tone control does effect the volume of the fault which would make me think it has to be in the first stage.

I had previously used the amp with the #0102 pre-amp and the Bluesmaster PI to see what the Ultraphonix thing was all about and the amp worked fine. (BTW the UP set up didn't really do it for for me, though the amp was hardy in a condition to fully appraise this sort of amp.)

I realised my entry is a bit too wordy, so the bold is for the skimmers to read quickly.

[talbany]

Mark
I think of the treble pot as a kind of mixer pot..(Treble cap fed to top and Bass pot fed to bottom) depending on where the pot is set determines the amount of treble or bass frequency's to be fed to the wiper.. Then on to the Vol.pot.. So in essence it's in the direct signal path of the stack (exiting) If this makes some sense.. It can be difficult for one to recommend a certain pot and say this one sounds best as we are now entering into a subjective area.. I will say that the older CTS pots do have a certain sonic flavor to them..
As for the bass thing..The first thing I would do is inspect each solder connection on V1 and in the stack using a magnifying glass and look for cold solder joints or solder that has not adhered properly..This is the first thing I would do!!..
Cold solder joints can act as a kind of diode effect this can cause all sorts of weird harmonic/buzz type effects you mentioned

Good Luck!!

Tony

[aflynt]

I've had bass related buzzing caused by shorting jacks vibrating on/off on more than one occasion. If the input jack is a shorting type, and you haven't already, check to see it's tightened up.

-Aaron