Harmon Kardon HD-970 modded, a world beater?

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Rafal hi, the only simple mod without going beserk like I did would be to change the SMD OP275 I/V opamps for something better, I would suggest SMD AD825's but these are singles and the OP275's are dual so you would have to find a 2 x single smd to single dual smd converter board, this would be the place to look.

Cimarron Technology, Inc.

Single-to-Dual Op-Amp Adapter - SO8 to SO8 version (p/n 031101A)

Cheers George

Thanks, did you heard how so-modified 970 is playing? How it will change sound characteristics of HD970 and is it worth to do this upgrade?
cheers
Rafal
 
From my experience with these two opamps as output opamps the differences are that the OP275 are a bit slow and tubey sounding, where the AD825 has slam and is very fast and detailed yet still sweet, but in the I/V stage ???????
I/V opamps should have good settling times and be quick and the AD825 is better than the OP275 in this regard, as well as having a good sound.
Cheers George
 
help needed with HD970

I want to upgrade my HD970 by replacing the OP275's with AD825's. And since I live in Holland where Tentlabs also is based I plan to add a XO2.2 clock with XO power supply too.

Does anyone (George perhaps?) has a schematic how to add these correct in the HD970?

Thanks in advance, Casper
 
extra info

I just found the oscillator in the schematics and added this as a jpeg.

I think I must remove the oscillator itself and L2, C53 and C55 when I add the Tentabs XO2.2 clock and connect the output to the Pin 5 location on the circuit board (and no other connections to the circuit board are made). The XO2.2 will then be fed by the XO power module. Am I correct?

Thanks, Casper
 

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