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CL Score....ZX500 and ZPA0.3 - My first PG Amps!
Posted: Sun Oct 24, 2010 3:53 pm
by bigdwiz
I just picked up my first PG amps today... ZX500 and ZPA0.3. I thought I was getting a ZPA0.5, but after further inspection it is a ZPA0.3. Strange how there is NO model # markings on the ZPA amp.
I'd rate the ZX500 at 8.5 and the ZPA0.3 at 7 out of 10. The ZPA's plexi cover is missing two corners where it appears someone tightened the screws too much (oops).
I put both amps on my test bench and they seemed to produce similar output to my 12" Infinity Perfect VQ sub. The ZX500 has bass controls and I'm guessing the ZPA had a remote bass control (no such score for me!).
I attached pics of each amp. Also, just curious from the PG enthusiasts...what would you say is a fair price for both of these amps? I've seen the ZX500 go for $250'ish on eBay, but not sure about the ZPA0.3. I've always wanted a MS series (275, 2125) or MPS, but came across these and decided to jump. I just hope I didn't fork out too much...
Posted: Sun Oct 24, 2010 6:41 pm
by tonym
what did you fork out?.....hehe
2 very good amps...will need to check the caps also....
Posted: Sun Oct 24, 2010 7:18 pm
by Stryker
The ZX looks very nice and clean,
I'm no expert but are you sure that isn't a point 5?
Posted: Sun Oct 24, 2010 7:45 pm
by kg1961
one hell of a deal

Posted: Sun Oct 24, 2010 11:26 pm
by bigdwiz
tonym wrote:what did you fork out?.....hehe
2 very good amps...will need to check the caps also....
$400 for both....how did I do? They were only listed as Phoenix Gold Amps...600w and 1000w. He was the original owner, but he had moved several times and didn't have anything but the amps themselves.
I'm guessing finding another plexi cover for the ZPA0.3 is not going to be easy? How about the bass control?
I've visually inspected the caps and they look good, but I've read some here about having them replaced. Is it recommended to get them replaced after a certain number of years?
Posted: Mon Oct 25, 2010 5:10 am
by shawn k
For $400...You definitely scored!! Nice pick!
Posted: Mon Oct 25, 2010 6:07 am
by tonym
good deal....
Posted: Mon Oct 25, 2010 6:24 am
by stipud
Definitely a great deal!
Those amps are almost 15 years old now, so if you want them to last another 15+ years, you should really replace the input and rail capacitors!
Posted: Mon Oct 25, 2010 7:06 am
by bigdwiz
shawn k wrote:For $400...You definitely scored!! Nice pick!
Good news! Are there parts available for the ZPA amps, such as the plexi cover or bass control?
Would I be crazy to want to swap the .3 for a MS or MPS series amp? My pref is for the "older school" amps, but I don't fully know the deal with the ZPA series. Can anyone enlighten me?
What was the original retail price of the ZPA0.3 (US$)? Anyone have a birth sheet with the actual output numbers?
Sorry for so many Q's, but I'm an old school audio freak....up to this point only collected RF and Orion. Not really sure why, b/c I doubt I'd ever put them in a car....
Posted: Mon Oct 25, 2010 7:24 am
by shawn k
MS and MPS amps are very nice as well.
The ZPA 0.3 is realistically a 600w amp
I can't remember what msrp was, but it was a lot...$1200 maybe? Fair value for a used one though, you're looking at $250-$400 depending on condition.
Just a bit of advise on the ZPA that you may or may not be familiar with though: These amps "need" a line driver in order to make full output. If I remember correctly, they need about 10v of input signal for maximum output. There are very few head units out there that have this kind of output voltage, so most will need a line driver with this amp.
Posted: Mon Oct 25, 2010 7:40 am
by Pillow
nice score! definitely a good deal in that condition.
The zx500 must have the caps replaced before use. I have only done 1 that the caps were not leaking.
Posted: Mon Oct 25, 2010 7:55 am
by bigdwiz
shawn k wrote:MS and MPS amps are very nice as well.
The ZPA 0.3 is realistically a 600w amp
I can't remember what msrp was, but it was a lot...$1200 maybe? Fair value for a used one though, you're looking at $250-$400 depending on condition.
Just a bit of advise on the ZPA that you may or may not be familiar with though: These amps "need" a line driver in order to make full output. If I remember correctly, they need about 10v of input signal for maximum output. There are very few head units out there that have this kind of output voltage, so most will need a line driver with this amp.
Thanks for this information, it is GREATLY appreciated! My Alpine 9813 puts out 4v, good to know more would be better.
The seller was asking $235 for the ZX500 and $300 for the ZPA0.3, sounds like he was about good on his asking prices. I guess it is difficult to turn down 4 Benji's if you need the cash!
Posted: Mon Oct 25, 2010 7:57 am
by bigdwiz
Pillow wrote:nice score! definitely a good deal in that condition.
The zx500 must have the caps replaced before use. I have only done 1 that the caps were not leaking.
Thanks for this information. I'll double check the caps and take more pictures.
Pillow, do you offer a service to replace the caps?
Posted: Mon Oct 25, 2010 9:24 am
by denim
The ZX looks perfect. 
Posted: Mon Oct 25, 2010 9:34 am
by Eric D
Nice score.
You can't really double check the caps. You have to remove them to know for sure, and when you remove them you have to replace them.
I personally don't feel the rail caps will be an issue, but the input ones are critical. Rail caps only get damaged from abuse. Input caps fail with the amp sitting in a box for 10 years, or the amp being installed for 10 years. Age kills them.
The pictures below WILL happen to you if you don't get these replaced...

Posted: Mon Oct 25, 2010 9:46 am
by ttocs
BOOM!
That is literally what can happen. If anyone here has never seen a cap explode, I highly recomend try it! Was the high point of my first freshman year of tech school.
Posted: Mon Oct 25, 2010 10:22 am
by bigdwiz
Wow, you guys are scaring me with the caps and exploding. I'm sure maybe someone here is an expert at replacing these? Is this an issue with other amps as well or only PG amps (or just a lifespan of capacitors)? I have some Rockford amps from the late 1980's and I'm pretty sure they have not had any work done to them.
Posted: Mon Oct 25, 2010 11:32 am
by Stryker
bigdwiz wrote:Wow, you guys are scaring me with the caps and exploding. I'm sure maybe someone here is an expert at replacing these? Is this an issue with other amps as well or only PG amps (or just a lifespan of capacitors)? I have some Rockford amps from the late 1980's and I'm pretty sure they have not had any work done to them.
All amps.... Think of an old flashlight , it doesn't work so ya crack it open to change battery's and whoa they have leaked everywhere inside. same concept. On a side note I have a VN condition Tbat(line driver, balanced signal F/S) for a good price PM me if ya want it.
Posted: Mon Oct 25, 2010 11:34 am
by Eric D
I don't think any RF amps have this problem.
The problem is with any PG amp from this older era, with Nichicon caps in the power supply. The caps leak (maybe a bad batch way back then), then the fluid shorts out and catches fire.
Some other old amps have this problem, but it just does not seem to be as widespread as with the PG amps.
Posted: Mon Oct 25, 2010 11:40 am
by Stryker
Hmmmm ^^^^ more of an expert than myself
go with what Eric says
Posted: Mon Oct 25, 2010 11:54 am
by bigdwiz
Eric D wrote:I don't think any RF amps have this problem.
The problem is with any PG amp from this older era, with Nichicon caps in the power supply. The caps leak (maybe a bad batch way back then), then the fluid shorts out and catches fire.
Some other old amps have this problem, but it just does not seem to be as widespread as with the PG amps.
I must say this is one of the most helpful forums I've ever joined!
I appreciate everyone's reply with the additional information. I think there should be a RF forum this useful!
Now, who's the capacitor replacer guru?
Thanks!
Posted: Mon Oct 25, 2010 12:13 pm
by bigdwiz
Stryker wrote:bigdwiz wrote:Wow, you guys are scaring me with the caps and exploding. I'm sure maybe someone here is an expert at replacing these? Is this an issue with other amps as well or only PG amps (or just a lifespan of capacitors)? I have some Rockford amps from the late 1980's and I'm pretty sure they have not had any work done to them.
All amps.... Think of an old flashlight , it doesn't work so ya crack it open to change battery's and whoa they have leaked everywhere inside. same concept. On a side note I have a VN condition Tbat(line driver, balanced signal F/S) for a good price PM me if ya want it.
I was a desktop admin for about 7 years and Dell had a capacitor issue back in the early 2000's. I had one or two PC's with "leaky capacitors" needing repair by Dell each week. They never exploded, just leaked onto the motherboard and caused a "thermal error" on bootup.
I'll get with you about that Tbat, thanks...
Posted: Mon Oct 25, 2010 2:16 pm
by smgreen20
To answer the question as to if you really have a 0.3, but yes it is a 0.3. You can tell by the resistors, the big white blocks along the side of the amp, 8 per side w/a space in between.
Real world power, to restate what Shawn K stated, is in the 675 watt area by 1 @ 4 ohms. Do the mod and you're looking at about 850 watts x 1 @ 2 ohms.
A 0.3 in that condition I would expect ~$350 and the 500, you where right on at ~$275.
Posted: Mon Oct 25, 2010 4:20 pm
by bigdwiz
I just found the original MSRP for the ZPA0.3 from someone's LOVELY scan of the CA&E buyer's guide in the PG Literature scans section....the .3 was $699 US and the .5 was $999.