Linear Power 3002 opamp change

[invecs]

Hi! This is my first post in here. Been reading about opamp rolling in here and I've been thinking of replacing the opamps in my 3002. It has the TL072cp...I've read that the best replacement is the OPA2134. Is the replacement just a drop in thing...or do I have to change anything else? And btw, what's the difference between the OPA2134UA vs the OPA2134PA?

Thanks.

[Perry Babin]

It's not always as simple as dropping in a different op-amp. Sometimes the circuits and the replacement op-amps are not compatible. In some instances, the op-amps will oscillate and can cause damage to the amplifier and/or the speakers. If you don't have an oscilloscope, you shouldn't blindly replace the op-amps. It's probably not a problem in this amp but you should know that there could be a problem.

The 'U' is a surface mount device. The 'P' is through-hole.

[invecs]

I see. I know quite a few people who tries to mod things...and almost ending up changing everything...kinda like a domino effect.

Thanks for the reply, Perry.

[1moreamp]

I have seen some of the TIPs modded PA-2's and such and when Burr-Brown or AD op-amps get inserted in these it seems that several capacitors in the circuit seem to get changed also. Along with the higher current draw these op-amps have you might be looking at a significant drop in the supply rails unless the power supplies are beefed up accordingly.

It looks a lot easier then it is, and requires significant engineering prowess to solve the issues you might create.

Plus I would start by cleaning up the power supply of ANY Linear Power product first, then worry about the overall audio circuitry...Hope this helps

[invecs]

I see. Maybe that's why TIPS doesn't have mods for the 3002.

I don't have any issues on how it sounds (it sounds good in fact)...it's just my spare amp and just want to play with it like some of you guys here are doing. I guess I'll just leave it as it is.

Thanks for the reply.

[manina]

Originally posted by 1moreamp
I have seen some of the TIPs modded PA-2's and such and when Burr-Brown or AD op-amps get inserted in these it seems that several capacitors in the circuit seem to get changed also. Along with the higher current draw these op-amps have you might be looking at a significant drop in the supply rails unless the power supplies are beefed up accordingly.

It looks a lot easier then it is, and requires significant engineering prowess to solve the issues you might create.

Plus I would start by cleaning up the power supply of ANY Linear Power product first, then worry about the overall audio circuitry...Hope this helps

Hi, can you elaborate a bit more on the last sentence? Why you are suggesting this? As I have few LP, I'm interested on any improvement that can be applied. Thanks

[1moreamp]

LP's amplifiers designs are OK, nothing really special, but they are functional, and fairly durable. Simple to repair for the most part. But the power supply just never impressed me, and I feel there is ample room for improvement in this area first before I would consider any upgrade to the basic amplifier channels.

If you look at say SoundStream, PPI, Diamond/Esoteric and many others they all added toroidal type noise chokes to the rails just after the main rail caps. They didn't do this for fun. It was done to smooth out the DC power and to block power supply noise from the audio sections.

LP amps could all surely use a power supply upgrade IMO. Theres a old rule about stereo that most people don't pay attention to much and that rule is " You must have power to make power", and hand in hand with that rule goes the secondary that " the power you have must be stable clean and useful"

Most folks overlook how important good clean ample DC power is in the picture of amplification. And I just feel that LP lets me down in the power supply area.

DC Preamp who worked for LP stated here on this forum that the Power supplies sag under load. among other things that get by to the amp channels. I just feel that it would be in everyones best interest to solve some of the weaknesses before you go throwing studio grade devices into these fairly average car amps.

No use in having ultra grade devices coupled with LOW grade power sources IMO. Plus I think it would amaze most people how much improvement could be gain by working with whats already inside the amp before jumping to add-ons that only amplify the original problems and issues the basic amp already had looming inside.

Again this is my opinion, but I hope you find it useful. I always found that the donkey pulls the cart, not the other way around. I hope you can see my line of thinking in this area.


Side note: the designer of the LP amps now works for TRU and if you notice he has upgraded his power supply designs considerably and has left transistor power supplies behind for all mosfet power supply design. Transistor power supplies left the car audio scene many years ago and I must say with my blessings. If it were up to me I would completely remove the old LP power supply and build my own all mosfet SMPS as a outside power source to supply the amp clean stable cool remote power to the amp. but thats just my line of thinking....

[manina]

Thanks! Crystal clear.

I agree the power supply is key to get a good sound out of an amp - it's just that I found the LP better than many other amps I listened (including PPI) so I'm interested in how can be further improved.

Unfortunately TRU is quite rare here in Italy so I can not make any comparison.

[1moreamp]

Check out their web-site they openly post the insides of their products, most of which still use TO-3's ...Some things never get old, if you know what I mean...

[winslow]

The designer of the LP amps does not work at or for Tru. Jerry has been at Kicker for a number of years though.