My new PIMETA pics (56K warning)

[thrice]

Well, I've built a PPA and a MINT, might as well finish it off with a PIMETA!

Here are some pics:

Specs:

AD8610/20 opamps
2 X 634 Buffers in L/R channels; 1 in ground channel
Biased to class A with JFET cascode
Gain set to ~5
Elna Cerafine caps
Wima C4 caps
Alps Pot
Battery or wall powered
Bulgin battery holders (Mouser part # 122-BX0026)
Neutrik headphone jack
Cardas RCAs (CTFA I believe)


A quick question: DC offset is good in the right and left channels (~.2mV), but it's 3.2 mV in the ground channel. This was a bit surprising (to me at least) since the MINT and PPA have a 0 mV reading in the ground channel. Is this ok? I'm assuming it is since anything under 10mv of offset is considered acceptable.

God I love this hobby!!

 

[evo_lution]

Nice work Thrice-excellent pics as well

 

[shw24]

wow.... very neat. I like the case, what case do you use?

 

[thrice]

Thanks!

It's a Hammond 1455N1201 case.

 

[Heady]

Nice built, thrice. What and where did you get the battery compartment? Thanks.

 

[thrice]

Quote:

Originally Posted by Heady Nice built, thrice. What and where did you get the battery compartment? Thanks.

The part number for the battery holder is in my first post.

 

[rayofsi]

looks a lot like one of mister x's pimetas =P

 

[thrice]

Quote:

Originally Posted by ufokillerz looks a lot like one of mister x's pimetas =P

Really? Oh well it wasn't intentional. I got the idea from one of Ray Samuels amps at the last VA/DC/MD meet. I had bought a couple of those Bulgin batt compartents and they are the same ones Ray uses on his XP-7 I think. Anyway, I thought I might be able to cram it into that particular case.

I have a few of the single 9V batt compartments too, but I think they may be a bit too big for a small Hammond case.

 

[MisterX]

Quote:

I have a few of the single 9V batt compartments too, but I think they may be a bit too big for a small Hammond case.

They will fit side by side in a Hammond.... you just got to tweak them a little.

Nice work.

 

[bg4533]

Does anyone else not see the pics? I looked earlier and they didn't come up either.

 

[Heady]

Quote:

Originally Posted by thrice The part number for the battery holder is in my first post.

Oops, blind as a bat. Sorry.

 

[flecom]

Quote:

Originally Posted by thrice A quick question: DC offset is good in the right and left channels (~.2mV), but it's 3.2 mV in the ground channel. This was a bit surprising (to me at least) since the MINT and PPA have a 0 mV reading in the ground channel. Is this ok? I'm assuming it is since anything under 10mv of offset is considered acceptable. God I love this hobby!!

how are you measuring DC-offset in the ground channel

you measure DC offset from ground output to left output and ground output to right output

nice work on the case, like the clean look

 

[thrice]

I also measure from ground input to ground output (as well as ground input to left and right output.)

 

[flecom]

Quote:

Originally Posted by thrice I also measure from ground input to ground output (as well as ground input to left and right output.)

thats not really DC-offset tho, becuase that doent matter its not going to your cans... all you have to measure is from L-out gnd-out and R-out gnd-out

 

[tangent]

A small amount of offset through the ground channel isn't anything to be worried about.