Experience with old PPI Art series?

[Meeks32]

I just purchased a PPI A1200 art series amp and was wondering if anyone has used one of these? I looked at a few pictures & I dont see any crossover controls on them. Im going to use it for my sub & am wondering if the crossover is internal with jumpers like old Orions or if there isnt one at all? I can just use the built in crossover on my Eclipse 8061 if not. Here are some pictures http://ampguts.realmofexcursion.com/PPI_A1200/

[dudeinaroom]

If memory serves you will need an external crossover. Do you know if your head unit has built in crossovers? If so, no problem. I miss the old PPI stuff, but if I had the money I would be getting me some old school class a soundstream amps. Those PPIs still rock

[killerb]

that is a great amp. i love the old school amps! i still have old rockford punch 40, punch 60, and punch 200 amps in my girls car. i also have a carver m-4120 and a u.s. amps tu-4360 tube amp laying around the house. old school amps are just quality through and through.

[Toxis]

mmmm Soundstream Class A10.0 and 5.0

Art Series... mmmmmmmmmmmm

[dudeinaroom]

just makes your mouth water.

[1996blackmax]

Nice pickup there.....

[PoweredByDodge]

i'm actually partial to the tarantulas

[avguytx]

I remember the A1200 (and most of that series) shutting off a lot because of the heat sink unless you added the radiator fluid. lol. They were great looking amps, though. I sold them when they were out back in the early 90's.

[PoweredByDodge]

remember the bazooka amplifier that came with antifreeze and a radiator pack -- hunk of shit only put out something like 400 watts anyway. an absolute joke... the radiator was purely cosmetic anyway (i'm sure it did SOME good, but it was wholly unnecessary for the amplifier -- it would have been far cheaper to produce the same amplifier with a slightly larger heatsink).

[1996blackmax]

I remember that....I always thought of those basooka amps as a joke, and more of a gimmick.

[Meeks32]

Alright I just received the amp last night & hooked it up for a little test this morning just to see if everything worked & all was good. But I have a question about the input sensitivity, the Art series have up to 2.5v & the outputs on my Eclipse deck are 8v. Should I have the amp modified to accept higher voltage inputs? or will this not be a problem?

[killerb]

you will have to turn the gains on the amp all the way down. at full volume you might be overdriveing the amp so just dont use the full volume on your head unit. you should test your head unit to see what volume setting will output 2.5v, that should be your max volume before over driving the amp.

[Meeks32]

Can I test that with a multimeter? or will I need to take it to a shop & have them test it?

[avguytx]

You will most likely have some system noise trying to feed 8v into something that is 2.5v max. Back when those amps were out, there were very few decks that even had 4v out! We sold the Alpine 7909 at that time and it was one of the top dogs at 4v output. One of my favorite CD players of all time.

You almost need something like a "reverse" line driver if there is such a thing. Something that can step down voltage for the inputs on the amp not to be clipped...which they will. I have no idea since after doing car audio from '79 to about '01, I don't care about it near as much any more. I rep it, but don't do it hard core these days. Maybe someone can chime in on that.

[PoweredByDodge]

Solution:

Set up a very simple voltage divider.

You want to preserve your 8v swing at the head unit, and you want to preserve your amplifier's gain utility, such that its full swing is functional.

As such, you need to cut 8v down to somewhere near 2.5v.

Simple...

Most head units will support up to 2 mA output current per RCA line-out channel. That being said, we can draw under 1.5 mA if we cut your input impedance down to 7 kohm rather than the nominal 10 kohm that is inherent to the amplifier as it sits. So the little divider won't 'over-draw' the head unit. Just be sure that you only hook up this one amp (with its little divider) to one set of RCA's -- normally you can hook 2 amps up with a Y-connector or "pass through" to one set of RCA's and be perfectly allright -- sometimes 3... in this instance, if you want it to work, you can only hook the one amp to one set of RCA's.

Here's a circuit diagram...

*** SEE ATTACHED PDF FILE ***

[PoweredByDodge]

ps...

- sandblaster -- $12 @ Home Depot
- heat sink compound and isolators - $15 @ Digikey
- primer + gloss [insert your favorite color Rustoleum] - $15 @ Home Depot
---------------------------------------------------------------------
- one badass lookin restored old school amp - priceless.

[killerb]

Can I test that with a multimeter? or will I need to take it to a shop & have them test it?

test it with a multimeter and a test disc. i dont have any problems with this method with my old rockford amps. they are 2.5v input amps also.

[PoweredByDodge]

test it with a multimeter and a test disc. i dont have any problems with this method with my old rockford amps. they are 2.5v input amps also.

technically you shouldn't have any problems. as long as you keep the volume level relatively low on the head unit. "full power" will be reached at 40 or 50% volume level rather than at 80 or 90% volume level. is this a 'problem'?

well, it depends.

if you care about noise, yes. if you don't, then no.

[killerb]

with his h.u. and the fact that the gains will be turned nearly all the way down should minimize noise. he can try your idea or buy -12db attenuators from harrison labs for about $25a pair. they both do the same thing. this will max the output at 2v from your h.u. remember gains are used to match the amp to the source. if it input of the amp is matched at 50% volume its matched at 50%. this will not add noise. volts are volts.

[PoweredByDodge]

noise is a fact of life that's picked up along the way
-- an 8v signal line picking up 1/2 volt of induced audible interference is only suffering from 6% noise.
-- a 2v signal line picking up 1/2 volt of induced audible interference suffers from 25% noise.

- 12 dBu / dBv attenuators
-- If they're placed as close to the amplifier as possible, then they'd have him right on at about 2.0 volts rms. that would be nearly ideal, and at 25 bucks a pair, that's a cheap fix. the key is to keep them close to the amp... same thing with my suggestion, it has to be kept close to the amplifier, else any benefit of an 8v line-out is wasted.

matched at 50%
-- that's pretty much useless. a head unit's volume control is not linear. the nice smooth dialing that is enjoyed throughout the range of control will not be present if 50% suddenly becomes the "new 100% limit".

[killerb]

noise is a fact of life that's picked up along the way
-- an 8v signal line picking up 1/2 volt of induced audible interference is only suffering from 6% noise.
-- a 2v signal line picking up 1/2 volt of induced audible interference suffers from 25% noise.
that is correct. but like you said the attenuators can be placed right at the amp inputs preserving the 8v signal until it reaches the attenuators.
- 12 dBu / dBv attenuators
-- If they're placed as close to the amplifier as possible, then they'd have him right on at about 2.0 volts rms. that would be nearly ideal, and at 25 bucks a pair, that's a cheap fix. the key is to keep them close to the amp... same thing with my suggestion, it has to be kept close to the amplifier, else any benefit of an 8v line-out is wasted.

i agree.
matched at 50%
-- that's pretty much useless. a head unit's volume control is not linear. the nice smooth dialing that is enjoyed throughout the range of control will not be present if 50% suddenly becomes the "new 100% limit".

i was just giving him an option if not using attenuators. i am using this option now for over 6 years with no noise issues. using no gain at all is the ideal setting and that is what i do with all my amps. this minimizes noise.