Hi all
I have been using T-amp for some time and I am very happy with it. But after doing the input mod (2uF paper in oil) my amp gets too loud too soon. I’m using the stock pot (50K). There no more smooth increase in loudness. My amp gets from silent (7 o’clock) to pretty loud (9 o’clock) and then slowly increases volume in the remaining travel. I’ve tried 2 stock T-amp pots and it’s the same thing. How do I fix this? Other value of pot (20k,100k) ? Or put a resistor somewhere? I removed R01 and R02 in stealth mod, so maybe that’s the problem?
I have been using T-amp for some time and I am very happy with it. But after doing the input mod (2uF paper in oil) my amp gets too loud too soon. I’m using the stock pot (50K). There no more smooth increase in loudness. My amp gets from silent (7 o’clock) to pretty loud (9 o’clock) and then slowly increases volume in the remaining travel. I’ve tried 2 stock T-amp pots and it’s the same thing. How do I fix this? Other value of pot (20k,100k) ? Or put a resistor somewhere? I removed R01 and R02 in stealth mod, so maybe that’s the problem?
luka said:
But then I would lose the bass benefits of the mod! Hundreds of people have done this mod and I have never seen reports of this behavior. I will try it if nothing else helps, thanks.
I guess you didn´t catch the concept. You change it back to see if the loudness effect remains or not. Only then you can see if it is caused by the new cap or something else...
Sounds like a wiring problem at the pot.
Can you post a diagram of how you have wired it?
Don't post what you think you did, post what you really did. Trace your wiring.
Can you post a diagram of how you have wired it?
Don't post what you think you did, post what you really did. Trace your wiring.
and a pic. Be gentle it's my first soldering job.
What I can say from the picture and the schema - you have just added extra caps in series to existing caps placed on the sonic impact board - this cant bring you any bass benefit, you gotta replace those onboard stock caps - which is a pretty tedious work since they are ver very small and the copper traces below the get destroyed pretty easily
then I would look for any possible shorts on board
or perhaps with those oil/paper caps you just hear the crappiness of the original pot 🙂
or perhaps with those oil/paper caps you just hear the crappiness of the original pot 🙂
Thanks for the photo and the schema. At 1st glance, all looks good. I'll do a little double checking later.
The problem you describe often comes when there is no ground to the center of the pot. The pot works as a voltage divider, dividing off your signal to ground. Without a ground connection, it can't do its dividing job, it just becomes a variable resistance in the path of the signal.
Your ground connections are the 1st thing to check. I suspect the problem lies there.
The other thing might be that you've got the pot wired backwards. Check that, too
BTW, are those SAFCO caps you've got there?
The problem you describe often comes when there is no ground to the center of the pot. The pot works as a voltage divider, dividing off your signal to ground. Without a ground connection, it can't do its dividing job, it just becomes a variable resistance in the path of the signal.
Your ground connections are the 1st thing to check. I suspect the problem lies there.
The other thing might be that you've got the pot wired backwards. Check that, too
BTW, are those SAFCO caps you've got there?
panomaniac said:
Thanks for your insight. I'll try wiring the pot the other way around, and then check the ground. I'm new to all of this, how can I check my ground with a multimeter to see if everything is ok?
Don't know what SAFCO is. These are Russian papers in oil, taken from an old medical instrument. I bough them from a guy who took the thing apart and was selling some tubes and caps. Here is a photo of one.
Attachments
Thanks for the photo of the can.
SIC/SAFCO is a French capacitor maker who makes (or made) very nice paper in oil caps. They look a lot like your Rusky caps.
Your soldering looks suspect. You probabaly have a bad solder joint on the ground wire.
To test: Set the volume at a reasonable level, like 7:00~9:00. Play some music. Wiggle the wires. If the ground is bad, but makes contact when you wiggle it, the sound level will drop, but not go away.
SIC/SAFCO is a French capacitor maker who makes (or made) very nice paper in oil caps. They look a lot like your Rusky caps.
Your soldering looks suspect. You probabaly have a bad solder joint on the ground wire.
To test: Set the volume at a reasonable level, like 7:00~9:00. Play some music. Wiggle the wires. If the ground is bad, but makes contact when you wiggle it, the sound level will drop, but not go away.
panomaniac said:
Today I tried reversing the signal wires on the pot (input and output), and everything snapped back to normal.
Thanks to everyone for their ideas and suggestions. I'm sure I'll be looking for your help again very soon, as I've just ordered AMP5 from 41Hz.
or the 
smilie to confirm.- Status
- Not open for further replies.