Op Amp for Reverb circuit HD130
I have an early release Music Man HD130 Reverb with the tube inverter. Chassis 2275-130. My tech told me that the op amp that drives the reverb is bad. I found a replacement, but how do I know which one it is on the circuit board? (There are seven of them).
Member for
10 years 9 months
Member for
9 years 8 monthsI'm no expert, but I see two
I'm no expert, but I see two LM307H IC's in what I think is the reverb circuit on the schematic. If I am looking at the guts of the amp from the front, there are seven LM307H cans -- from left to right, would that be the 5th one? I think I am just going to order 7 of these from littlediode.com and just repace them all. I will post what happens. This amp sat with hardly any use from 1980 until now. It was a beast for me back in the 70's. I had this fully recapped recently, but it still much noisier than I remember it being "back in the day". Hopefully changing out the op amps with do the trick...
Member for
10 years 9 months
If it has sockets, did you
If it has sockets, did you try pulling them out and wiggleing them around to clean the pin? Slight corrosion can do the same thing. Mike.
OOPS-according to little diode, they ONLY have 1. You might look into the brown dog adapters and use current issue opamps. There have been discussions here about the use of the new ones a lot.
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9 years 8 monthsMember for
10 years 9 months
Here-look at this thread.
Here-look at this thread.
Member for
10 years 9 months
Member for
9 years 8 monthsMember for
10 years 3 months
LM 107?
You can still get the round metal can versions in LM107.
http://www.ti.com/lit/ds/symlink/lm107-n.pdf
http://www.sayal.com/zinc/zinc_SEARCH.asp?txtSEARCH=LM107
Member for
10 years 9 months
Yes, they are available in
Yes, they are available in limited quantities but at usually a ridiculous price in some cases. Just my opinion but a couple of guys(Ok- mainly Ed Goforth-one nice guy) here have done the hard work and TRIED the available current opamps. In my case, if I have to do mine, it will get something current. They are only going to get harder to find. Just my 2c's worth. Mike.
You REALLY need to ask him
You REALLY need to ask him which one. There are more than one IC's in the reverb chain so "driver" may not be the right choice of words. Ask him if he meant the one that is directly before the tank. That would be IC-5. OOPS-forgot to ask if you had IC sockets or are they hardwired in? Mike.