JLM Hybrid opamp for Master channel of Yamaha M1516

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bluezplaya
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JLM Hybrid opamp for Master channel of Yamaha M1516

Post by bluezplaya »

I am trying to beef up the master section of my Yammy M1516 with some super snappy fast opamps to offset the softer channel strips. The board is transformer balanced and has a nice warm tone but seems to lack presence and definition in the mids. I was thinking I could modify the line amp in the master section with the JLM Hybrid running in A/B mode but don't know if that's what I need to do. As you can see in the schematic below (page 1) the PGM master uses a Toshiba TA7322 9 pin opamp for the summing amp and buffer amp. The line amp appears to be transistor based. This is where I am confused, as I don't know if this means it is discrete or Class A or whatever. I'm not too familiar with that type of circuitry and it's sound characteristics. Would the summing amp and/or buffer amp affect the overall sound, or just the line amp?


YAMAHA M1516 schematic
http://www.adamholtmusic.com/diy/M1516/M1516Master.pdf


TOSHIBA TA7322P datasheets
http://www.adamholtmusic.com/diy/M1516/TA7322_1.tiff

http://www.adamholtmusic.com/diy/M1516/TA7322_2.tiff

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Joe Malone
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Re: JLM Hybrid opamp for Master channel of Yamaha M1516

Post by Joe Malone »

The line amp appears to be transistor based. This is where I am confused, as I don't know if this means it is discrete or Class A or whatever. I'm not too familiar with that type of circuitry and it's sound characteristics. Would the summing amp and/or buffer amp affect the overall sound, or just the line amp?
The line amp is discrete transistor running in Class A/B. It is built out on the PCB's in the M1516 but in the PM2000 the line amp circuit is in a small potted box with the same pinout as the 2520, 990, JLM99v, Hybrid which makes changing the opamps easy. The summing and buffer will effect the sound definitely.
Joe :-)
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bluezplaya
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Re: JLM Hybrid opamp for Master channel of Yamaha M1516

Post by bluezplaya »

So the PM2000 is using the NE80200 or NE80100 (don't have schematic) for the line amp. That's nice. Joe, you say the buffer amp and summing amp on the master channel affect the sound; what suggestions do you have for changing those and/or the line amp?

Thanks,
Adam

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Joe Malone
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Re: JLM Hybrid opamp for Master channel of Yamaha M1516

Post by Joe Malone »

So the PM2000 is using the NE80200 or NE80100 (don't have schematic) for the line amp
The NE80200 and NE80100 potted amp circuit are the same line amp circuit as your 1516 line amp has built out on the open PCB. I don't know of any direct fitting opamps to replace in the Toshiba TA7322 9 pin SIL opamps directly. You could hand wire a hybrid into the SIL pinout but it would be messy. Normally in the PM2000 we just change the group line amps since they have the same 990 pinout so we get 4 stereo sets of groups with different pairs of JLM99v , Hybrid etc so there are 4 sets of different sounding stereo outs. Not sure what you could do with the M1516 as it is not so plug and play as the PM2000.
Joe :-)
JLM Audio
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