Sunday, January 11, 2015

1966 Ampeg Reverbrocket 2

This was a nice project. Problem was it cut in and out. The screen grid resistor was fried, filter caps were going bad.

                        Burnt 470 ohm 2 watt resistor:

I always make it a point to replace these with 2 1k ohm 5 watters in parallel. A lot of current can be drawn on the screens of these tubes and I've seen this resistor burned up just due to that.

In this case it was the filter caps failing so this one got a full re-cap:

Grounded plug too. Always sand where you intend to ground to insure a good solder joint. I've seen many amateur grounded plug jobs gone wrong and the results can be disastrous!

This amp was re-covered at one point but the circuit had never been touched and the alnico CTS speaker is original. All dates are super close: 

 In combo amps I always pull the speaker to check for any tears and to remove any dust hanging around the edge of the cone. Good for avoiding that "it has a buzz" call after the customer has taken their amp home!

Unfortunately the reverb tank was dead so I replaced that as well. Amp sounds lovely now even with it's old Ampeg labeled 7591 tubes (test good but I recommend replacing them in this amp as they are showing their age! The Sovtek or Tung Sol version is quite nice. JJ? Risky. Amp is cathode or "self" biasing so you can just buy a matched pair and drop them in.) and gives up a nice even tone with my trusty Esquire. These amps tend to be nice jazzers for those of you who dig a hollow body guitar.

No comments:

Post a Comment