Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Please login or register.

Login with username, password and session length
Advanced search  

News:

collapse
Pages: 1 [2]   Go Down

Author Topic: Sunn Concert Lead PA  (Read 4694 times)

gbono

  • Elite SSGuitarist
  • *****
  • Chip Points: 5
  • Posts: 141
    • View Profile
Re: Sunn Concert Lead PA
« Reply #15 on: August 23, 2010, 01:37:29 PM »

I spent some time testing the preamp sections on this amplifier - Sunn used JFETS in the input stages of their design (Concert series). The original part is a "glob top" (preceded TO-92) package - 2N4304. I tried using Fairchild J201's and though they had the same PIN OUT and similar IDSS specifications they produced more 2nd order spurs (without change the circuit) - the PN4303 is still available and seems to give about the same results as the orginal part - FYI

I had to rebuild much of the signal path of the second channel including sourcing a new reverb pan.

Now to dial in the bias for the best distortion/power dissipation at idle.

Thanks for the help.
Logged
Pages: 1 [2]   Go Up
 

* User Info
 
 
Welcome, Guest. Please login or register.
Did you miss your activation email?
* Recent Posts
New Single End Amp by Littlewyan
[Today at 05:11:06 PM]


sound city clean-up by ilyaa
[Today at 05:08:47 PM]


behringer GMA 100 miniamp by Roly
[Today at 10:54:58 AM]


Amp safari continues by Roly
[Today at 07:33:24 AM]


Another cool but dangerous antique by Bajaguy
[April 23, 2014, 04:51:49 PM]

* Sponsors