Upgrade LM318 to OPA627 in Musical Fidelity P170?

Upgrading LM318 to OPA627 in Musical Fidelity P170 may have problem. Below is an extract of a thread on a DYI forum regarding swapping LM318 for OPA627 - there are a few issues with dropping them straight in "They're LM318's - it was suggested some improvement might be had by swappingthem for 627's, which I have coming with the caps, as I'm sure they will getused elsewhere if not on the P170... I think I've been infected with DIY..I'll have a go at creating a full schematic of the amp, and I'll upload ithere and send it to Mr Hennesy, maybe he'll archive it on his site...Maybe on the weekend...MichaelA 8Hennesy should have the schematics, I think I sent it to him some time ago.Regarding swapping the 318, I seem to remeber that there are no dc ofsetadjustments only a freq-compensatio pins/curcuits/components that you needto disconnect. Other then that it should work as is. The 637 will probablymake the amp go into oscillation.maf_auOk, I have the schematics, thank you Mark and A 8 :)Here is what I see on pins 1 and 5 on the 318:Pin1 via 3K3 and 2n2 to Pin5So should I just hook them out and swap in the 627?Regarding replacing the caps, especially the 22,000uf jobs on the PS:How should I (safely) discharge them before working on them?Is running the amp disconnected from the power for a while enough todischarge them, or should I ground the + terminal as well? Not wanting toget fried this week, and aware of the potential for stored current in thesepuppies...At this stage, I'm going to replace caps, repair board and re-assemble. Ifeverything behaves at that point, I'll swap the opamps.MichaelamplifierguruFirstly, if you have any power resistors around say 5W'ers then work outfrom the supply voltage stored on the caps whether they would be in theirratings if placed across one C to ground i.e. P=VxV/R. Then just hold it on-the the other(s).The RC on pins 1,5 sound like comp for the 318. I haven't used one fordecades. Can you post the amp schema..Cheers,Gregmaf_auquote:Originally posted by amplifierguruFirstly, if you have any power resistors around say 5W'ers then work outfrom the supply voltage stored on the caps whether they would be in theirratings if placed across one C to ground i.e. P=VxV/R. Then just hold it on-the the other(s).The RC on pins 1,5 sound like comp for the 318. I haven't used one fordecades. Can you post the amp schema..Cheers,GregThanks for the reply!Ok, bear with me, I'm new to this. I've got the bit about grounding the capto earth via a power resistor, but calculating the load:P=VxV/RAm I on the right track here:I'm thinking that V= the tranny output volts, R= the power resistor valueohms, so assuming I had a 5k/5w resistor, and the tranny was putting out63v:P=63 x 63/5000 = 0.79 (watts?)So, my 5watt/5k resistor would be fine, and turning the eq around, I'd needa 793.8ohm/5w resistor or better?I've asked A 8 if it's ok to post the schematic...Thanks,MichaelA 8They are for [...]