Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => EZ Board postings => Topic started by: Geezer on June 18, 2005, 06:31:27 am
-
Hoffman Amplifiers
> Tube Amp Building - Tweaks - Repairs
> increasing bass response
<< Prev Topic | Next Topic >>
Author Comment
vinman753
Junior tube assistant
Posts: 104
(4/20/04 11:34 pm)
increasing bass response
--------------------------------------------------------------------------------
i built a super reverb type amp with doug's ab763 design. I use channel two mostly.
The amp sounds and works great, but i would like to increase the bass response.
i have the bass pretty high and the middle down but i still would like a little more bottom.
would changing the tone caps to a different value help me out? If so, a couple of suggestions? Thanks.
GroundhogKen
Forum Moderator
Posts: 2350
(4/21/04 7:25 am)
Re: increasing bass response
--------------------------------------------------------------------------------
Change the .047uF cap in the tone stack to .022uF. That's what you will find in a real Super Reverb.
If you want more thump. Increase the .001uF cap at the input to the phase inverter to something larger, but don't go higher than .01uF. If it gets too muddy and honky or if you get blocking distortion, reduce the value to something closer to .001uF.
Ken
Searing
Junior tube assistant
Posts: 87
(4/21/04 12:31 pm)
Re: increasing bass response
--------------------------------------------------------------------------------
I put a .022 in that spot, reccomended by Gerald Weber into my twin and it sounds good. Just wondering why Ken said not to go higher than .01? Will it damage something?
Chris
GroundhogKen
Forum Moderator
Posts: 2352
(4/21/04 12:56 pm)
Re: increasing bass response
--------------------------------------------------------------------------------
Since Fenders use .1uF caps to couple the PI plates to the power tube grids, and since long tail phase inverters have input resistance greater than 1 meg, using a large cap at the phase inverter input is a recipe for blocking distortion and fartiness at high volume levels.
For AB763 style guitar amps, I think 500pF to .0033uF works best at the PI input.
Ken
vinman753
Junior tube assistant
Posts: 105
(4/21/04 2:16 pm)
Re: increasing bass response
--------------------------------------------------------------------------------
thanks a lot guys i appreciate the help
<< Prev Topic | Next Topic >>
Topic Commands
Click to receive email notification of replies
jump to: Tube Amp Building - Tweaks - Repairs (New)New Product Suggestions (New)Praises - Complaints - Suggestions (New)Buy - Sell- Trade (New)Archives (New)
- Hoffman Amplifiers - Tube Amp Building - Tweaks - Repairs - Hoffman Amplifiers -
Powered By ezboard® Ver. 7.32
Copyright ©1999-2005 ezboard, Inc.