I did a test like this also, with Genesis DM, Celestra RA220, Audison Sedici and a few other PG amps. I found the ZPA0.5 the best PG amp on sound in my home system. The difference with other PG amps is the pre-amp stage, there are no opamps in it. Just my opinion...

The capacitor is 470nF M5E Murata 50V see the pictures:

I think the gateresistors are 1/4 watt. I check for the other parts, I have a M100 for repair here. Did you did the pcb "transplant" with epoxy?

It's in the house...

Just clean the board with IPA and carefully test it without a load.

For smd parts you can use a smd codebook like http://www.marsport.org.uk/smd/mainframe.htm. Sometimes transistors are difficult to find. Try to get the power supply working first. Just remove the rectifiers after the torroids, then you can test the power supply without any load.

I think I did one a few years ago. It's just an amp, a big one but nothing special
I check my repair notes.

This afternoon I succeed in putting all the parts on the pcb and it's working! Opamps are the National LME49720, I allways use this one when possible, very low distorsion, nice sound. But Burr Brown OPA2134 or Philips NE5532 are very nice... Also did a mod on the input sensitivity, 0,2-2V range is a...

I'm going to replace the gainpot from the M44 sub-part to the M25, and add the components needed for the gain pre-amp (opamp, resistors, caps, rca sockets). Only adding a gainpotmeter and the rca sockets is not enough... 8) There are some very good M25 for sale overhere, but way too expensive for th...

Today i did succeed in analyse (and draw) the inputcircuit of the M25, just a single gainstage and bypass the useless bassboost section, tbc...

The original M25 pcb is exactly the same as the M25 part of the Route 66, but only the gainstage potmeter, RCA sockets and all the caps/resistors/opamps are not mounted on the pcb. So you only heave to drill three holes...
If someone knows a M25 for sale, please PM.

Thanks, but i knew that one. The purpose of my mods is to make a 6ch fullrange with 6 inputs from the route 66. There are a lot of 6ch DSP's to drive this nice amp.
So I need a M25 and replace this for the M25 in the Route 66...

I'm modding a Route 66 (M44 + M25) to a full 6 channel amp, with 6 inputs (normally 4). Therefore I need to transform the M25 pcb in the Route 66 into a real M25, with RCA inputs and gainstage etc. I need a defect M25 (or a very cheap one :) ), or a sharp photo of the resistor/capacitors.... Thanks ...

For testing the power supply only, you can remove the rectifier diodes. The smps runs without a load and then you check the symmetrical voltages (squarewave).
Rob.

When a power supply has a blown mosfet, I useally replace all the mosfets and when you replace a transistor/mosfet in the amplifying part, check afterwards the DC-offset and biascurrent (voltage on the emittor resitors).
Testing i do on a dummyload of 2 or 4 ohm resistor, 50w or more.
Rob.

I do repairs on all brands car audio, and i'm a bit expirienced ;-) First I measure with a DMM the transistors on the board when I meaure a wrong value (shortcircuit or high value, or else...) I desolder the transistor from the pcb and check it on hFE en all the PN's With this amp two small drivertr...

Today I finally (after a year...) repaired a ZPA0.5, the caps on the primairy side were leaking and a driver transistor (2sd1763a) was defective which causes a shortcircuit. Now the idle current is 2,5A. I was reading in the specs that they take 0,75A idle, which is very low for this kind of amp. I ...

Ok thanks, Eric. I will also measure the bias and do some adjustments to get both channels at the same level.
Only a Genesis class A (DM-A) and Audison Sedici/Trenta are at the same level of (high) bias of 2-3A per channel.
Rob.

I just recapped it, and was searching on specs of this little beast. Now upgrade it to 4x 10000uF instead of the 2x 10000uF + 2 x 4700uF original rail caps.
So 8 amps idle current is normal?
Rob.

Can somebody tell me what amount of idle current the ZPA 0.5 is doing? I read in the manual 8A, but I think thats a lot of A...
Thanks!
Rob.

Hi Brian, I will have a look at the capacitors in your amp. As I understand there are no WIMA's in there right now. WIMA is a good brand for foilcapacitors MKT or MKP so exchange is a (small) increase in SQ. The better type foilcapacitor is MKP, but they are larger and maybe they doesn't fit on the ...

No, that's not necessary. It has to the same or higher.
Rob.

You can put bigger in, with the same or higher working voltage. So original 4700uF/35V can be exchanged with 6800uF/63V.
But......most of the time they won't fit on the pcb or in the heatsink, just to big (diameter or hight).
And try to find low ESR types, like Panasonic TSHA or FC.
Rob.

The silpads I only exchange when they are in bad condition. When they are looking OK, why changing? Isolation and heatconduction don't change that much I think.
Rob.

For member martinkruit, I'm refurbishing his MAC200 amp. I did also all his other amps (I think.. :lol: ), some nice pics from exchanging caps. http://www.12vhifi.nl/pix/mods/IMG_3627.JPG http://www.12vhifi.nl/pix/mods/IMG_3628.JPG http://www.12vhifi.nl/pix/mods/IMG_3631.JPG http://www.12vhifi.nl/pi...