Results 1 to 4 of 4

Thread: Negative feedback adjustment on a Peavey Classic B

  1. #1
    Member
    Join Date
    Aug 2010
    Location
    Fayetteville, AR
    Posts
    50
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    10

    Negative feedback adjustment on a Peavey Classic B

    I have a Peavey Classic 410 (hybrid). I was thinking it would be interesting to see what effect changing the amount of NFB on this amp would have. Can the negative feedback loop be modified for adjustment on this amp? I'm familiar how this works with a tube preamp, but I'm unsure if it can be done with a transistor preamp. I see on the schematic what appears to be the NFB loop with a 68k resistor in line from the OT heading back to the transistor (I assume PI) at the bottom of the schematic.


    peavey-classic-b-schematic.pdf

    0 Not allowed! Not allowed!

  2. #2
    Lifetime Member Enzo's Avatar
    Join Date
    May 2006
    Location
    Lansing, Michigan, USA
    Posts
    32,036
    Thumbs Up/Down
    Received: 1,822/7
    Given: 0/0
    Rep Power
    55
    The NFB is part of the power amp, not preamp, in either type technology.

    Yes, that pair of transistors is exactly that, a phase inverter.

    NFB is NFB, it works the same with transistor phase inverter. The NFB is a 68k/10k voltage divider. You can play with that ratio if you like, though I'd be surprised if it did a lot.

    0 Not allowed! Not allowed!
    Education is what you're left with after you have forgotten what you have learned.

  3. #3
    Member
    Join Date
    Aug 2010
    Location
    Fayetteville, AR
    Posts
    50
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    10
    Ah, I meant to type PI instead of preamp in that sentence. Yeah, doing some research on this type of power amp, it seems like it is designed not to flavor what's being fed into it, but to be linear and not care too much about tube specs.

    0 Not allowed! Not allowed!

  4. #4
    Lifetime Member Enzo's Avatar
    Join Date
    May 2006
    Location
    Lansing, Michigan, USA
    Posts
    32,036
    Thumbs Up/Down
    Received: 1,822/7
    Given: 0/0
    Rep Power
    55
    That is exactly it. Peavey made their power amps to be strong and clean, the amp's tone would be generated in the preamp.

    0 Not allowed! Not allowed!
    Education is what you're left with after you have forgotten what you have learned.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Replies: 4
    Last Post: 01-23-2017, 07:39 PM
  2. Negative feedback removed from Peavey Classic 30
    By Ernest Ball in forum Guitar Amps
    Replies: 3
    Last Post: 06-14-2013, 03:12 AM
  3. negative feedback question
    By paul525715 in forum Theory & Design
    Replies: 5
    Last Post: 05-10-2010, 04:33 PM
  4. Peavey Classic 30 bias adjustment
    By Philr228 in forum Mods & Tweaks
    Replies: 7
    Last Post: 05-02-2010, 11:39 AM
  5. Applying Negative Feedback
    By EETStudent in forum Theory & Design
    Replies: 9
    Last Post: 07-28-2008, 01:37 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •