[Chadly]

Is it bad that I plan on using Carbon film resistors in my amp instead of metal film resistors because that's what I had in stock? Will the amp sound differently? I want it to sound exactly like the Grado Ra-1 that I'm replicating.

Thanks,
Chad

 

[HD-5000]

Hi Chadly, yes Carbon Film should alter the sound a bit but in another thread you said you were going to use OPA2132? That should alter the sound of the amp a lot. I'm hoping to someday build an RA-1 clone too, but I have 2 JRC 4558

that I picked out from my Denon DCM-370 and replaced with the OPA2132's.

 

[Chadly]

Thanks, I'm not going to be using the 2132, I'm just using it to build the RA-1 until my 4556 chip arrives. Will the Carbon Film affect the sound with the 4556 chip?

Thanks,
Chad

 

[Wodgy]

If you're planning to use your amp with Grado headphones, I think you might even prefer the sound of carbon resistors to metal film ones. Carbon resistors tend to be a bit warmer -- this matches nicely with Grados since they lean towards the bright side.

 

[Chadly]

Thats really great news Wodgy. Thanks, I was just into Mouser going to make an order but I really don't want to wait any longer to make my amp. DIY electronics is sooo fun!

Thanks,
Chad

P.S. It's hard to find 465k and 122k resistors. So I'm using 470k and 120k. Those are close enough values right?

 

[Wodgy]

Definitely, those are perfect. Enjoy building your amp!

 

[rickcr42]

Quote:

P.S. It's hard to find 465k and 122k resistors. So I'm using 470k and 120k. Those are close enough values right?

No problem with the values but you really must match the resistors for L/R channel or you may end up with an amp that is louder in one channel.

Since headphone amp just about never have balance controls resistor matching is critical !

 

[pocomo]

Quote:

No problem with the values but you really must match the resistors for L/R channel or you may end up with an amp that is louder in one channel.

How close do they need to match?

 

[rickcr42]

as close as the accuracy of your ohmeter will allow , really ; very important for the stereo image