[was ist los?]

Hi all, as you may or may not know, i was building an RA-1 clone with a BUF634T output, but encountered some trouble. Well i finished about a week ago and cased it.
It has X-feed and 3 x BUF634Ts/channel running in wide bandwith mode. I am still waiting for a JRC4556, but the pics show it having an OPA2228. This project was cheap considering i had most of the parts lying around such as the buffers and i stripped my old RA-1 clone to rebuild it. I picked up x-feed parts for around $5 and $10 for switches. I spent another $10 for the 24v Elpac that i got off ebay! It's the one tangent and others have recommended. Also, the case i got for free.
Heres a link to pics: http://f1.pg.photos.yahoo.com/ph/cha...c=ph%26.view=t

Kinda messy because i reused the board and the wires are a mess.

 

[uniuniunium]

the opamp is coming, i swear :-D

 

[Ajit]

I mailed your op amp on Monday from Chicago. Should reach you this week..

 

[yongchao]

I am interested in the same project also, may be can contact me, ooiyungchaw@hotmail.com.

i have a few grado amp opamps, but don't have buffer, so i am thinking of making them into Apearhead design, or i get a few cheap opamp and convert them into buffer.do you think it works.

 

[PeterR]

Hmm, one of the few strongpoints of the 4556 is its 70mA output current, which you don't need to drive the 2Megohms of your buffers...Maybe after all you'd be better off with another opamp?

 

[was ist los?]

Well i got a JRC4556 and popped it in. Sounds great and it sounds amazing. Super great bass slam, nice full mids, and extended highs. They go well with my SR-60s. I just hope my SR-225s(arriving in two weeks) will go well with my Gilmore that doesn't work...Ugh
Yongchao, what do you want me to tell you about this amp? I'll be happy to answer any questions you have. You can leave a message on this thread, PM me, or email, which ever is most convient for you.

 

[Jupiter]

Quote:

Originally posted by PeterR Hmm, one of the few strongpoints of the 4556 is its 70mA output current, which you don't need to drive the 2Megohms of your buffers...Maybe after all you'd be better off with another opamp?

So with the JRC4556 the amp will perform better without buffers?



was ist los,

where did you get the JRC4556?

 

[was ist los?]

They are available from www.mouser.com , but some members donated some to me. They are around $0.29. I think they are better with the buffers, much better even though it can supply so much current already. The buffers help with the low end. Don't expect miracles with this chip, it only sounds good in the RA-1 circuit, that Marantz designer must have figured out the best synergy for it.

 

[PeterR]

Quote:

Originally posted by Jupiter So with the JRC4556 the amp will perform better without buffers?

No I was wondering whether it wouldn't perhaps sound better with another opamp in place of the 4556...

 

[Budgie]

The biggest problem I know of with this chip is even though it can put out some juice, the distortion starts to rise to fairly high levels as the impedance of the load drops. It probably sounds better driving the input of the buffer then it would driving the headphones directly.

 

[rickcr42]

try the original grado opamp but doubled

not the "47" type circuit but the "makie" type using two devices in parallel

the bass slam you noted with the buffers will be there and with less current draw

just be sure to use a 10 ohm or so resistor on each opamp output