4 x LM4780 mono, OR 2 x LM4780 stereo: Will I notice the difference?

[mondogenerator]

Well if it works then obviously no problem with them.

I expected larger heatsinks for that many ICs though.

 

[UrSv]

Well, if I stay with them long enough to need to worry I can simply bolt another heatsink on the outside

 

[danielwritesbac]

PSU fluctuations and isolating that side of things hadn't occurred to me, and I agree Daniel, LM1875 for tops would be nice....but I don't have any! I have 4780, 3875, 3876, 3886...

Both of your posts make a great deal of sense to me, and I was only just starting to consider HOW I was going to approach the PSU/s, I considered that shared PSUs wouldn't be ideal. I had no idea it was such a bad idea. Thank goodness I didn't try it.

Perhaps then I should use one 4780 parallel per channel for bass, and then either: A single 4780 for highs, with separate PSU(Crosstalk shouldn't be too bad? its a stereo IC isnt it?) Or just a pair of 3875/6/3886 instead.

For mids&treble amplifier, see Decibel Dungeon for the inverting mode LM3875/6/LM3886 amplifiers set up to sound a LOT like LM1875's. Nice, stable and cool running, with a pleasant tone, such as you probably didn't expect. The Decibel Dungeon Gainclone index page with links to all chip amp articles. See also the NE5534 preamp (good dynamics clarity and bass slam) which can run class a with Signetics, Philips or Raytheon chips, or a simpler construction with class ab for other makes.

Parallel LM4780's should make for excellent bass amplifiers.

P.S.
Isolation for stereo crosstalk can be done very much like ordinary battery isolators, except easier. One channel amplifier board shown:

Going in in v+, going out on v-. Presto! Virtual Dual mono, and diodes are cheaper than regs (albeit the appearance of regulators is more orthodox than diodes). 6a05, 10a1 standard silicon types of diodes may be used for this. You'll need at least 440u per rail (or more) capacitance directly at the chip for the approach shown to be fully effective.

 

[mondogenerator]

Thanks Daniel, ive read the DD stuff a few times, and indeed it is one of the sources that persuaded me to give this a try.

I have a bunch of 4562 and 49710/40, although i realise that in the most part opamps aren't rollable, as many would believe. But the 5534 is an unusual beast. If i need a preamp it may be useful, so thank you.