pro-ject phonobox se opamp substitution

karloss · 12th December 2010, 07:26 AM

hello
i'd like to mod pro-ject phonobox se - change opamps and caps. using only mc and 100ohm, should i change all four 4580D or only one pair is used at this setting? Would like to use opa2134 as a direct replacement. Or should i forget about this and better build something new? Any suggestions? Thanks a lot.

PMA · 12th December 2010, 09:50 AM

Even NE5532 would be much better, than the 4580. For the input stage, you have to keep the BJT opamp. You may try NE5532, but much better choice would be ADA4898-2, but you would need SMD/DIP8 reduction then. For further positions behind input IC you may try NE5532, OPA2134, but again - ADA4898-2 would be the best option.

karloss · 12th December 2010, 10:02 AM

so at 100ohm mc all four 4580d are active? i saw cambridge 640 that seems like there is separate mc and mm stage. isn't that in this pro-ject the same? why i'm asking - i have two bb opa2604 left from cd player upgrade. thank you very much

PMA · 12th December 2010, 10:55 AM

I do not know the circuit diagram. If you have it, send it to me by e-mail, and I can advise you then.

Regards,

12th December 2010, 09:50 AM	#2
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	Even NE5532 would be much better, than the 4580. For the input stage, you have to keep the BJT opamp. You may try NE5532, but much better choice would be ADA4898-2, but you would need SMD/DIP8 reduction then. For further positions behind input IC you may try NE5532, OPA2134, but again - ADA4898-2 would be the best option. __________________ Pavel Macura http://www.linkedin.com/pub/pavel-macura/4/783/637 http://web.telecom.cz/macura/audiopage.html

12th December 2010, 10:55 AM	#4
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	I do not know the circuit diagram. If you have it, send it to me by e-mail, and I can advise you then. Regards, __________________ Pavel Macura http://www.linkedin.com/pub/pavel-macura/4/783/637 http://web.telecom.cz/macura/audiopage.html

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12th December 2010, 10:02 AM	#3
karloss diyAudio Member Join Date: Dec 2010	so at 100ohm mc all four 4580d are active? i saw cambridge 640 that seems like there is separate mc and mm stage. isn't that in this pro-ject the same? why i'm asking - i have two bb opa2604 left from cd player upgrade. thank you very much