My new general question thread. (Renamed rectifiers and bl..

[tribi9]

That depends. What type of amp is it; or do you have a schematic for it?

It's a stock Vibrochamp. [IMG:800:468]http://i114.photobucket.com/albums/n271 ... layout.gif[/img]

[M Fowler]

Here is a raw control that weber utilizes.


Better known as a tone stack bypass control, this allows you to lift the tone stack to effectively reduce its effect on the tone. This gives you more of a raw, un-eq'd tone. The kit includes the pot with a push-pull switch, and a knob.

[tribi9]

So what the push pull pot is achieving is just breaking the ground. Could anything bad happen if I just lift the ground on the pot and run it like that?

[tribi9]

Here is a raw control that weber utilizes.


Better known as a tone stack bypass control, this allows you to lift the tone stack to effectively reduce its effect on the tone. This gives you more of a raw, un-eq'd tone. The kit includes the pot with a push-pull switch, and a knob.

Ok, I see how it works now. I would have to drill an extra hole for this then.

[Structo]

No you can buy a push pull switched pot in the value you need, no need to drill an additional hole.

[tribi9]

Ok, so I ended up doing some mods to the amp. I wanted it cleaner and a bit louder.

I ended up completely removing the bass, treble pots from the circuit. I also did some of the Gerald Weber mods that "tweedify". the amp I guess.
I wanted to experiment since I'm fairly new to all these. As soon as I removed the tonestack I got a nice boost. I can't control the bass or treble but I usually just keep them on max anyway. So I don't really miss them.

I removed the NFB and it seemed to sound nicer (to my ears at least). Then I changed a couple of values on some resistors and caps.

The most noticeable change in tone happened when I swapped the 470ohm cathode resistor. I put a 1k 5W and also upped the bypass cap (Is that what is called?) to 50uf @ 50 V. That made the amp cleaner and better sounding. It also brought down the plate voltage.

I also found a NOS stock cap in .02. I used it as I figured I'm using it as a coupling cap so it should be ok. Please let me know if it's not ok. (It's the red one in the pic)

A lot of changes. I'm really impressed with the sound. Its like a bigger, cleaner, fuller sounding amp. It overdrives much later maybe around 7.

Another question I have is I want to put a pot for the NFB where the trem output is. There is a hole there on the chassis that I'm not using. Does that pot need to be grounded? I only have 250k now audio. Will that work?

Here are some before and after pics.

Sorry to have 2 threads on the amp this one was just going to be a general question but since I only have the one amp I built, it just turned into a thread about the amp.

I'll just keep this one running for any future questions.

Thx guys.

BEFORE
[IMG:800:600]http://i114.photobucket.com/albums/n271 ... c02085.jpg[/img]


AFTER
[IMG:800:600]http://i114.photobucket.com/albums/n271 ... C02347.jpg[/img]

[IMG:800:600]http://i114.photobucket.com/albums/n271 ... C02348.jpg[/img]

[tribi9]

Since I got no answer to my las post. I went a head and installed a 250K Audio pot on the NFB. I had an extra white knob kicking around.

Cheers guys,

Here's a pic of the back of the amp.

[IMG:800:600]http://i114.photobucket.com/albums/n271 ... C02349.jpg[/img]

[tribi9]

I'm going to post some voltages, hopefully someone can let me know if these voltages are too high for the 6V6.



Pin 3: 404 V

Pin 4: 403 V

Pin 8: 29 V

If I understand correctly the plate voltage would be then 404 V - 29 V? Correct? Which would be safe for a 6V6 right?


I have a 1K 5W cathode resistor and a 470 Ohm 5W screen grid resistor.

I`m trying to get a little more clean headroom would upping the screen grid resistor to 1k help me achieve that?

Sorry about all my noob questions am trying here.


Cheers guys and thnx for your help.