volume loss

[antiunderscores]

hey guys,
something seems to be up with my amp. I've been mucking around with the preamp but after some problems i've gone back to the original design (although its pretty stupid)
Anyway, now the volume is pretty dam low and i have logarithmic pots (i think thats what they're called, they're the one where the volume goes up evenly throughout a turn.) and now its really quiet with no real volume to speak of until it gets to about 7 then there is a sudden rise in volume until the top. However this full volume is about equal, to 4 on the volume before i mucked around with it. Any hints about whats going on?

[Chuck H]

Thats not much to work with. You basically just said: 'I've been messing around with the circuit and now it's not as loud as it was'.

Did you use the same value pot for the log as you had when it was linear? Did you change anything else?

You might start by putting the old pot back in. If the problem persists you can eliminate the new pot as the problem.

Chuck

[antiunderscores]

sorry, my description must of been confusing. It was the same pot and before i was mucking around it was loud and volume went up smoothly. Now there is absolutely no volume until i turn it up towards the max and even then it is comparatively quiet when compared to what it used to be.
I rewired the preamp the same way it was before but i also changed the speaker out lead as the old one was playing up. I'm convinced the problem is in the preamp but im not sure if it is before or after the volume control.
Hope that information helps. Thanks for your reply though.

[txstrat]

I would think the pot is wired wrong way. Did you double check whether all the wires go to the tap they're supposed to go?

Hope this helps

Matt

[pdf64]

What's the amp?
Best to put everything back as close as possible to where it was , ie including speaker cable, and see if problem still exists. Peter.

[antiunderscores]

the amp is unknown. Its basically the chassis with all the parts installed (no "box" around it) and im pretty sure it was just a general purpose amp, i had to put 1/4 inch jacks in. Its wired pretty weird because all the treble bass and volume are wired before the first preamp stage but everytime i try and change that i get very little, very distorted sound so i think i';; try mapping out the entire schematic to see whats going on, doesnt sound half bad though. i'll try changing the wires to the pot around now.

[antiunderscores]

i switched the joints on the volume pot around but it didnt really help. A few more things to ad. I've replaced most the capacitors in the amp, all the resistors are tock, when i [power up a hum slowly gets louder then just disappears and when i turn up the volume the hum gets louder then at certain points it creates a *pop* noise and turns pretty quiet. At the moment i can comfortably play at full volume but before i wouldnt really dare push it much past half way so effectively the volumes been halved.
To expand a bit on the layout of the amp. It begins with the volumes control, etc. then it goes to the first preamp stage and then the other half of the tube (2nd preamp stage) but at the input of the second stage there is a wire that leads to a small group of resistors and largish capacitors (except one which is 330 pf) and this wire creates a really loud pop when u disconnect/reconnect it.
hope that helps a little bit more.