Need help from someone at PG on an MQ430

[Eric D]

Does anyone have an MQ430 which may also be in need of new caps?

Since this is quite a mystery, I offer to replace the caps and test your amp. If it only 3V, I will update it as well. All I ask is you pay shipping and parts, I will eat the labor.

[Nils]

Both of mine needs new caps, but i think it's a bit expensive to test some of mine MQ's

[ttocs]

Would be happy to help you out dude if you can/will make it sound better. That is at least if you use some "special caps" and replace the wire as well since we all know that will make such a great difference.....

I am hoping to make a trip to the post office shortly so let me know your address and it could be on its way shortly... My caps have been pulled, just not replaced. I already have them just been too lazy.

[Eric D]

Would be happy to help you out dude if you can/will make it sound better. That is at least if you use some "special caps" and replace the wire as well since we all know that will make such a great difference.....

I am hoping to make a trip to the post office shortly so let me know your address and it could be on its way shortly... My caps have been pulled, just not replaced. I already have them just been too lazy.

Sounds like a plan. Step one is to replace all the wire with pure silver. Step two is to instal some 1 farad rails caps, step three is to replace the gain and bass pots with some nice 6in diameter switched resistor arrays. I can go on and on.

Sure your amp may weigh 10 times what it does now and not fit into any installation, but it will sure sound excellent!

[ttocs]

lol I would almost pay for a pic of a 1f cap hangin off that board, though the case sticking up another full 10". that would be funny as shit, but then again every little bit helps and more capacitance is ALWAYS better!

[wooferdog]

this mq-430 is going to have to be mounted upside down

[ttocs]

bet it would reject noise if you wrapped it in foil! More is always better!

[wooferdog]

my mq now has so much reserve i can start my truck with no battery in it! lol

[kg1961]

that made me laugh thanks for the pics...

[Nils]

Now i have checked mine

REV B # 430846 all are 510ohm 5% tollerance (this one has two extra railcaps, small size)
REV C # 431934 all are 510ohm 5% tollerance (this one have only the big railcaps)

Have you listened to both of these amps? Do they have the same output?

Sorry Eric i didn't got the time to check the output on these two, but i manage to build me a "A-B testing device" that makes the ab testing a little easier I'll try during this week..

Nice pic wooferdog

[finbar]

Rev C board, 510 ohms, 2.8V with the gain at half . I don't have an oscilloscope to see clipping.

[Eric D]

Rev C board, 510 ohms, 2.8V with the gain at half . I don't have an oscilloscope to see clipping.

How does it sound? With low output (which yours seems to be like mine was), you will hear it start to clip early on, and it will not really get all that loud on a set of speakers.

[stipud]

Stupid question, but what about the preamp? Is yours the correct one?

[wooferdog]

that made me laugh thanks for the pics...

that cap took a while to find, last time i used it was in 96 or 97

Now i have checked mine

REV B # 430846 all are 510ohm 5% tollerance (this one has two extra railcaps, small size)
REV C # 431934 all are 510ohm 5% tollerance (this one have only the big railcaps)

Have you listened to both of these amps? Do they have the same output?

Sorry Eric i didn't got the time to check the output on these two, but i manage to build me a "A-B testing device" that makes the ab testing a little easier I'll try during this week..

Nice pic wooferdog

thanks Nils

[finbar]

Rev C board, 510 ohms, 2.8V with the gain at half . I don't have an oscilloscope to see clipping.

How does it sound? With low output (which yours seems to be like mine was), you will hear it start to clip early on, and it will not really get all that loud on a set of speakers.

My input voltage was low.
Revised results, @ full gain 0.8V input yields 19V @ the speaker terminals, no speakers connected. 1KhZ.
With speakers connected I get good output at 1/2 gain.

My resistor code reading may be bad, here is a board shot......

[Eric D]

I got my hands on a MQ430 REV-B, and it did 12V a channel output. What is strange though is someone has worked on this amp before. There was a lot of evidence of parts being replaced in the preamp section. All four pots are 10k ohms, and two of them should be 50k ohms. The work looks like it may have been done by PG, so this amp could have been sent in for repair some time ago, and they made adjustments too it.

12V is still not the 16V I had got from the other MQ430 I had messed with, but is WAY better than only 3V.

[ttocs]

I assume that is my amp I sent you? Interesting....

[Eric D]

I assume that is my amp I sent you? Interesting....

Yep