ms amps, lpl44 upgrade possible?

[marko]

always a pity that pg never incorperated the lpl feature in the ms line of amps, but is this mod possible?

i just swapped x-overs out and don't have remote bass level anymore so just set and forget but i miss being able to "crank" it up once in a while

[1moreamp]

The LPL circuitry is a LM13600 chip. But I would put back the PG crossover, or any crossover that has LPL in it, as its simpler and less of a headache to deal with.

All of the LPL circuits use the same chip except MTX amps They use a custom chip. I have the pdf floating around here somewhere, but theres fails and the 13600 seems rock solid, as I can't remember ever replacing one yet, but I have repaired the MTX chips on several occasions ... C

[marko]

i could use an ax204a purely for sub duties but this is an 18db slope design and the frx456 is 24db slope design, i don't have a preferance but right now the 24db design is working great in my set up...

i guess it wouldn't hurt to try.

[1moreamp]

i could use an ax204a purely for sub duties but this is an 18db slope design and the frx456 is 24db slope design, i don't have a preferance but right now the 24db design is working great in my set up...

i guess it wouldn't hurt to try.

Run the 204 after the PPI X-over and run a wide range sip module way above the crossover point so it has absolutely no crossover effect but the LPL will be 100% there for you

[marko]

that's an idea, but i'm against having too many things in the rca signal chain, i believe every time a signal passes through something it degrades it (to a lesser extant i know but...)

this is one reason i ditched the kef ke6, too complicated,
more to get wrong and more to degrade the signal.

the frx456 does exactly what it says on the box and no more, it's a x-over it doesn't even have gains, but my amps have gains anyway

[1moreamp]

To get LPL your adding a LM13600 to your circuit so either way your adding something, and on Bassline I doubt you will ever hear it due to its limited bandwidth and most normal folks hearing ability is pretty poor at low end, not like the high end at all. Thats why the industry is submerged in class D amp for bassline. Most people just can't detect the difference at that low end like that.

PPI used a optical encoder to drive a chip inside there amps called Q-bass. I'm looking at my spare encoder NIB right now, So PPI never had LPL per say.
Even if I dug up a simple circuit you would still need to mount it inside the amp or the crossover so iy could get powered up properly and shielded from noise. A possible quicky pre-built module would be a Kicker LPL module from the ZX ZR line of amps its all built and all connections are located at the card edge that plugs into the amp. Just add RCAs and +&-15 volts from either the crossover or the amp, and run your phone cord to the control a 10 Kohm pot. I have one of these also for testing of amps on my bench.

Try to stay away from the cheap imitations on e-bay that are nothing but a dual gain pot with 20 foot RCAs these change impedance loading of the circuits and therefore introduce sonic quality changes along with the ~20 to 40 feet of RCA cord.

Best of luck and cheers Marko C

[fuzzysnuggleduck]

And here I was thinking the LPL44 was so simple...

Wrong again!