2*5*2*0 Op Amp - How much space underneath?

[Category 5]

I got my two 1973 2*5*2*0 op-amps today, but it looks like they were the soldered variety and the pins appear to have been cut. There is approximately 2mm of pin left at each position, but I am thinking that there will not be enough meat to leave any clearance under the modules when I install them.

Since the circuits are built facing downwards I was wondering if I can safely mount the modules flush with the circuitboard without problems.

Thanks!
Shane

 

[Category 5]

P.S. Is there a way I can test the modules with a multimeter before i get my preamps built? ...or do I need the built preamps?

Shane

 

[soundguy]

shane-

2520s are mounted flush with the board on all the api gear I have.

dave

 

[al_p]

[quote author="soundguy"]2520s are mounted flush with the board on all the api gear I have.[/quote]

same here, mostly.

 

[Category 5]

cool. I guess since they are early versions that's just how the pins look. It looks like they are just made from copper wire that was snipped at the end with wire cutters. They are not all identical in length but are close.

Now that I examine them more closely it looks like there is solder on the cut point (just tinned, as it seems someone removed the solder quite completely) which would indicate that they were cut before they were soldered.

Anyone have a unit not installed whod care to descripe the condition of the pins?

Also, short of installing it in the module (which I am still waiting on parts for) is there anything I can do to check these?

Shane

P.S. Supposing I build some of Fabio's replica op-amps later on....how would I go about potting those? Where do I get he epoxy resin?

 

[jrmintz]

[quote author="Category 5"]Anyone have a unit not installed whod care to descripe the condition of the pins?[/quote]

I have two different eras - white and blue label with long tinned pins, and gray labels with long gold pins. I'm not sure if the gray labels are old or reissues, I have to check.

 

[Category 5]

Thanks Seth.

What is the difference between the blue ones and the black ones. I had a chance to get some blues cheap, but didn't think they would work the same. For some reason i thought the blues were for power amps, but now that I think about it if the part name is the same then the part must work the same.

Would you care to comment on their sonic differences? Slew rate? Amount of Gain...etc. Should I build a couple of pres with the blue face units too, or will they just be the same as the Melville, NY ones?

Thanks!
Shane

 

[jrmintz]

I'm not sure, but I have the impression that the differences are relatively minor, component choices or board layouts, maybe some surface mount devices. There have been some discussions about this, I think at the old place. It is still, as a practical matter, the same part. I've never done a careful comparison, and I've never seen a spec sheet for the newer ones. API has gotten very sticky about letting information out lately. Several years ago they happily sent me a bunch of information about my 550As, recently they absolutely refused to send me anything on my 553s. It would be interesting to try an opamp A-B sometime, but the time never seems to be available. My guess is that the transformers you choose will make a bigger sonic difference in a preamp than the opamp version, but that's just a guess. Anybody know what the version differences are?

 

[soundguy]

I guess when you consider the amount of people totally profiteering off the api name I dont blame them for putting everything under lock and key, I think if I was in their same position, Id do the same thing... Its easy to figure that one of the main reasons why there are so many neve clones is the crushingly thorough documentation that neve provided about the modules... I think if there was an 80 page book for the 550a like there is for the 1073, we'd probably see more of those cloned by others... so far the only guy to really clone the eq is a guy that fixes maybe more of them than anyone...

FWIW, I have a bunch of 325's that have different generation black 2520's on them and while I've never sat down to do an under a microscope A/B with them, I never noticed much of a difference between the modules at all. Compare that to changing out the caps for panasonics where I heard a HUGE change in sound from one to another with bc caps. Its quite possible that the blue ones might sound slightly different if possibly you had it next to a black one for comparison but I speculate that in a mix youd have trouble picking it out, if its a 2520 you are doing pretty good... I'll take whatever blue ones you decide not to buy...

When you build your pre's, the caps you should definitely listen to are the axial BC's available from digikey, they are the same phillips caps that were in the api consoles originally and they have the same ballsy midrange. I dont notice too much change between old api amps with original caps and the ones Ive replaced with the BC caps and I tried a lot of caps before trying those and wasnt digging anything until I tried the bc's. Good news is they are really cheap, well, cheap compared to black gates. If you are looking to get close to the real api mojo, Id definitely take a listen to those for sure.

dave