[runeight]

The inputs are balanced but can be driven SE for both versions.

 

[ericj]

Details are coming.

One thing I'd like to point out, that $325ish number pabbi1 gave is all-inclusive.

You can stuff both the PS and amp boards with Mouser parts, and that Mouser order is under $200 including the iron.

All you need aside from that is the boards, suitable hookup wire, a socket compatible with your chosen headphones, and a box to stick it in. And a power cord for the filtered IEC inlet.

A determined cheap person could bring it in under $250.

 

[sachu]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif Details are coming. One thing I'd like to point out, that $325ish number pabbi1 gave is all-inclusive. You can stuff both the PS and amp boards with Mouser parts, and that Mouser order is under $200 including the iron. All you need aside from that is the boards, suitable hookup wire, a socket compatible with your chosen headphones, and a box to stick it in. And a power cord for the filtered IEC inlet. A determined cheap person could bring it in under $250.

Agreed,

I would actually say this can be put together for about 225-230. Mine totals to about 275 and that includes the 8$ RCA jacks, 10$ shaft extension kit, 14$ knob ,32$ potentiometer and a surplus case that cost me 7$.

 

[HeadphoneAddict]

That is just amazing!

This weekend we'll get to try O2 Mk1, Jade, HE60, SR-404LE, and Smegma Pro with wiatrob's. I'm assuming it's Pro bias, or I'll have to grab my SR-Lambda as well for normal bias.

 

[les_garten]

@Pabbi1

are you getting any hum with this setup?

 

[wiatrob]

The rigs at RMAF will be fully balanced (one may have a switchable set of SE inputs) - but will use two pots (RK27s) for volume control in keeping with the affordable nature of this amp...

 

[HeadphoneAddict]

Quote:

Originally Posted by wiatrob /img/forum/go_quote.gif The rigs at RMAF will be fully balanced (one may have a switchable set of SE inputs) - but will use two pots (RK27s) for volume control in keeping with the affordable nature of this amp...

Bill, do you want me to bring two balanced DAC's with me to RMAF? Also, how much more costly is one balanced volume pot vs having the two volume pots?

 

[dBel84]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif A determined cheap person could bring it in under $250.

how about an uber frugal CB

..dB

 

[ericj]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif Bill, do you want me to bring two balanced DAC's with me to RMAF? Also, how much more costly is one balanced volume pot vs having the two volume pots?

four-deck pots are uncommon -- iirc the Alps blue one approaches $50, vs. $13-$17 each for the regular stereo pot.

 

[dBel84]

you could always use a single shunted deck for balanced operation - there are a few threads that deal with this option ..dB

 

[wiatrob]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif That is just amazing! This weekend we'll get to try O2 Mk1, Jade, HE60, SR-404LE, and Smegma Pro with wiatrob's. I'm assuming it's Pro bias, or I'll have to grab my SR-Lambda as well for normal bias.

That will be a very nice comparo!

Both amps will have Pro and Normal bias jacks simultaneously available and we can tweak the high bias for the phones of your choice - provided they plug into a 'standard' Stax Jack or you have an adapter cable.

 

[wiatrob]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif Bill, do you want me to bring two balanced DAC's with me to RMAF? Also, how much more costly is one balanced volume pot vs having the two volume pots?

Thanks for the DAC offer, I'll have my DACMagic, but we can chat offline about it.

AFA balanced pots go - you could always add a nice stepped attenuator and double the parts cost of the amp!

I have a candidate balanced and affordable pot here, I'll be wiring it up and if it works well it might go into one of the amps.

 

[dBel84]

That adjustable bias makes me think that those panel led meters will be very handy ..dB

 

[smeggy]

this is gonna be sweet!

Can't wait to get one of these up and runing

 

[wiatrob]

Quote:

Originally Posted by dBel84 /img/forum/go_quote.gif That adjustable bias makes me think that those panel led meters will be very handy ..dB

You mean something like the attached?

We've (er, I've) investigated, and while it can be done, there are a few caveats (most of these require additional 12V DC power, and the stat bias supply voltage is easily pulled down...)