#68 fender bandmaster full#
He wants to learn and I think a full rebuild/cleanup makes the most sense. With white lettering and they look original? Solder blobed onto the eyelet board - the eyelet board is warped.Īny suggestions for replacements for the paper coupling caps, they are blue The soldering job from the factory does not look very good with too much Is there a modern recommended 5% carbon comp resistor for these old amps? Many of the resistors haveīeen replaced with carbon comps from Radio Shack that just do not look right. The electrolytics with a kit and those look fine now.
I opened up the amp and I didn’t see anything blown or connections loose. He got this amp fairly cheap and it has been worked on a lot. When I plug into the second channel all my tone disappears and I’m left with a sterile foggy tone. Backed off the tone nuts and reseated them, now Tone controls also did not work in the Normal channel and I noticed that theĦ800 ohm at the bottom of the tone stack was grounded through the case of Noticed that the 1 M grid leak resistor was grounded to the Wiring, carbon comp resistor values, voltages around the pins and everything The first stage grid of that channel caused bursts of oscillation. He said that the Normal channel was not right and I found that just tapping Put a dummy 4 ohm load on it and drove the input with a function generator. selector here:įorgot to provide links in post #5, Twin Reverb schematic: It is interesting that several Orange amps have a selector switch for that cap probably to match the amp to the speaker cabinet and what the player wants - deeper response vs. 005 uF is best for lead with a 64 Hz -3dB point. I think that they would sound better with a lower cutoff.
Having thought about it more, it was probably done to limit speaker excursion given that these were usually open back cabinets, and to allow them to play louder before OT saturation comes into play. So, we calculate the -3dB point for the 300 Hz example, then at 150 it would be 9dB down, and at 75 Hz 15 dB down. It would be a first order 6 dB/oct slope until the other RC networks come into play but those are probably much lower.
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