a newphyte; hello to all, and a question regard neve cards

hello all,

i'm obviously new to the forum. here's some background: i live in seattle, wa; i work on tube amps for a living; i like building things.

i bought some BA283 half filled cards from Dan Alexander awhile back, and they've been sitting around for quite a while. i did manage to get some card sockets. i was thinking about getting those 1290/rotary switch cards from JLM Audio. i was also planning to buy some sowter transformers from prodigy pro. what i need to find out is what kind of resistors and capacitors should be used for stuffing the cards that i bought. i'll replace all the electrolytics, and i'm planning to use metal film resistors. are there any kinds of capacitors that work especially well in the neve circuits? i've heard that tantalums are used in some areas. is there something i should know about trying to get these circuits to work before i jump in head first? any thoughts/comments are appreciated.

I dont have the docs in front of me, off the cuff-

On the unstuffed side of a 283, in the upper right there are three electrolytics, try BC axials available at digikey, those are closest to the caps that were used originally. There are a few tantalums which will be shown as radials on the board screen. You can get avx or panasonic from digikey and both are fine. Ive used the JLM switch kit and its great and Joe is beyond great to deal with. You can jump in and buy the card and add it from the start, or try the amp first and see if it will work for your needs with a regular switch and a bit of boost from the existing two amplifiers on the card.

dave

[quote author="soundguy"]You can jump in and buy the card and add it from the start, or try the amp first and see if it will work for your needs with a regular switch and a bit of boost from the existing two amplifiers on the card.[/quote]

from what i've read, Joe's card is a rotary switch for the gain attenuator, but also an additional gain stage to make the 1272 a 1290 in effect. i'm not sure if i need the additional gain of a 1290, but i do know that i'll need an attenuator of some sort if i want to make a proper neve clone (i've heard of some circuit that uses a potentiometer for gain adjustment...is this acceptable? i'd sure be a lot cheaper). so if i just wanted to find a 12 step rotary switch, where could i get one?

and thanks dave for the all the info in the previous post!

I'd go with the caps Dave suggested, and go for the 1290 preamp.

It's worth the extra work and I think quite different sounding than a
1272.

I too got my parts from Dan. The second gain stage is the same as one of your half filled 183 or 283 cards.

Maybe someone can help here with a source for a 3X12 gain switch.
( I found one in my junk pile)

cheers,
Lance

[quote author="hitchhiker"]It's worth the extra work and I think quite different sounding than a 1272.[/quote]

how does it sound different, if you don't mind expounding?

The second gain stage is the same as one of your half filled 183 or 283 cards.

Click to expand...

so i basically make two gain stages instead of one? if that's the case, i could in theory just make a few extra 283 cards from artwork i've found, and then just wire them up. is that right?

I agree that the 1272-type 2-stage design sounds different at higher gains. Describing it, however, is tricky at best given the fact that almost everyone's 2-stage version is different, though in general (I've heard 3-4 different implimentations) 1272's get a little 'fuzzy' feeling, while the 3-stage designs stay clear and solid.

I think both are worth having, myself, and particularly for louder sources (drums, elec. guitar, etc...) the 3rd stage pretty much doesn't get used, so why not have a few channels of the simpler one? A schematic of the 2-stage circuit I use is posted on the '1272 for newbies' thread if anyone's interested.

BTW, I also have some 3x12 shorting switches that I found surplus. As it turns out, they are actually 3x13 switches that are punched with a stop at 12 positions. I disassembled a couple and used a dremel tool to grind away the stop, and now they're 13 positions again, absolutely perfect for a 3-stage, 1290-type Neve preamp (20-80dB in 5 dB steps is 13 positions ). They have solder tabs and have never been used, though they are somewhat dirty, though an ultrasonic cleaning does wonders.

If anyone would like one of these PM me. They're $4 each (I couldn't believe my good fortune!!!). I only dremeled the ones I've used so far, the others are still 3x12. Let me know if you'd want me to mod them for 13 positions.

Peace,

JC

rascal,

how big are the switches? could you get some pics up by chance?