[jboehle]

Here's some **** of my 2nd PPA. It's the PopPA Muse - PopPA (for "PPA"), Muse, cause it uses Nichicon Muse caps.

The stats:
OPAG - Burr Brown OPA627BP
OPAL/R - Burr Brown OPA637BP
C1 - 8x 330uF 25V Nichicon Muse KZ
C2,C3,C5 - not installed yet
C4 - 6x 100uF 25V Nichicon Muse FG
RESISTORS - Vishay-Dale 1/8W RN55D 1%, hand matched to .1%
C6G - 100pF silver mica
BUF - 12x Intersil HA3-5002
POT - Alps Blue 50K
IN - Neutrik locking 1/4", black
OUT - 2x Cardas GRFA female RCAs
POWER IN - Neutrik PowerCon
WIRE - green Cardas 21.5 awg
CASE - extended length Hammond, black
SOLDER - Cardas Quadeutectic silver/copper/tin/lead

Less than 1mV DC offset on each channel - PERFECT!

I will get it cased up tomorrow. Haven't hooked up the bass boost or class A biasing yet. I am also going to install Tangent's crossfeed board. Thinking about adding a high/low gain switch, too.

I ran out of 2N5486 JFETs, that's why the ground channel only has 2 of them, instead of 4. Those are on order!

The amp seems to be behaving ok w/o the bypass caps installed - although I've only driven some crappy, very low impedance 'phones with it so far.

At the bottom you can see my custom Neutrik PowerCon -> 5.5/2.5mm power adapter. It uses a couple short lengths of 18 awg Belden Teflon-insulated silver-plated copper hookup wire internally. I made it so I could use an Elpac wall wart until I build a STEPS power supply for this PPA.

Enough talking, lets get to the ****!

-Jason

 

[iWeasel410]

*drool*
Very nice job! I'd like to step up from my CMoy but I don't think I can afford something like this just yet

 

[was ist los?]

Why do you need that Neutrik plug and jack, can't you just use the normal cylindrical plug? BTW, does the Neutrik have 3 conductors?

 

[jboehle]

I don't "need" it. I used it for the "cool factor".

Yes, it does have 3 conductors.

-Jason

 

[ITZBITZ]

Nice look board -- I love the look of the Muse caps. The black/gold is an eye catcher. Too bad it's trapped inside the box once the amplifier is finished.

 

[Nisbeth]

That's a seriously powerful headamp if you need a 30A connector for the PSU

/U.

 

[Mindless]

Looks sweet.

However, dosent it feel a bit booring to build the same amp in the same case as everybody else?

Sometimes there are some really impressive ideas but mostly it is this "Hammond" case in either black or grey/aluminium.

Anyway, hope it sounds nice. (BTW : I was not complaining on your work, hope you understand, just find it a bit booring that everyone builds the same)

 

[jboehle]

Yes, it is a bit boring to see the same thing over and over again, I agree. Which is why I try to do at least a couple of unique things or use some unique parts when building my amps. I found a new, cool, heavy-duty, large-diameter volume knob for this PPA. I am also going to mount all the panel-mount components from the insides of the panels, which will give it a somewhat unique look. The use of the Neutrik PowerCon plug/jack is the first I've seen in my short time here on the forums. I also used the extended length Hammond case, so I'd have more room to work at the rear of the case. I added the crossfeed today, not many pics get posted of amps w/ crossfeed. I know all of these are little things, but it's those little things that help to differentiate your amp from others. I'd love to build in some of the more exotic metal cases (which there aren't many of), or build a custom wooden enclosure (but I don't have the necessary woodworking skills or tools). The Hammond enclosure is just so hard to beat...the board fits it perfectly, it looks decently cool, and it's not too outrageously priced. I plan to build a STEPS power supply for it in an extended length Hammond case to set right next to it. When that is complete, I might just get up the inkling to order a large front & rear panel set from Front Panel Express, that would span both of the cases, holding them together.

Oh, and maybe you hadn't seen the last PPA I built (sold it recently to a fellow Head-Fi'er):

You can find more pictures of it here.

I thought that one was pretty unique. Yeah, it was in the standard Hammond case....BUT the clear panels were all custom manufactured for it by me. I think I might do a clear top for this PPA too...it just seems a shame to spend so much time and labor building something so cool looking just to cover it up in a black case.

-Jason

 

[qwerty870]

wow. permanent bass boost

 

[jboehle]

A PPA without bass boost is like a cheeseburger without cheese.

(ppl had a better saying along those same lines, but it's no longer in his sig, so I had to make up my own)

The bass boost I had in that one only boosted real low and not by much, it added that little bit that most headphones roll off too much - just perfect!

-Jason

 

[tangent]

Quote:

ppl had a better saying

"A PPA without bass boost is like a spring morning on TV."