Populating Neve BA283 AV, Any Advantage to......

I'm about to populate a BA283AV card. I also have an original. Are there any advantages in using carbon film (or comp) resistors in this circuit? I don't know any of the original component brands except for the Electrolytic caps (Philips which is now BC). I'm a stickler for accuracy.

And about the 2N3055... I read a comment from Geoff Tanner how these should only be Motarola or Newmarket (never heard of the latter), otherwise sound may suffer. What do you think?

Regards,
John

Carbon comp resistors are generally considered as inferior.
From what I've read their only advantage might be in signal paths with a very high DC voltages and very high AC swing (like a tube power amp's phase splitter)

Other than that their just noisy...

dunno about the transistor. I remember reading the OnSemiconductor 2N3055 was ok in this circuit but I don't really know if it makes any difference...

I'd stick with metal film. Regarding the power transistor, you may as well stick with recommendations if they exist and you haven't already purchased parts. Yes, it may not make any difference, but then it may.... and there's no point in risking going for something inferior.

If you praise accuracy, don't forget Polystyrene Caps (Styroflex)

Whoops said:

If you're a stickler for accuracy, don't forget Polystyrene Caps (Styroflex)

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True. There is good reason for that in this instance. Don't forget the correct voltage tants as well.

rodabod said:

Whoops said:

If you're a stickler for accuracy, don't forget Polystyrene Caps (Styroflex)

Click to expand...

True. There is good reason for that in this instance. Don't forget the correct voltage tants as well.

Click to expand...

Thanks for the tips guys. Any info on what brand of tantalum caps they used? I very well may just stick to a modern day equivalent, but I like to have the option of knowing the original brands used. Caps are not the best "vintage" things to buy though, with them losing their capacitance over time and all.

Tantalum caps improved a lot since the old days when they were not that reliable,
so probably you'll be better with modern day equivalents.

Rodabod, could you please tell me what's the reason for the Polystyrene caps in this project?

I used them when I built mine but just because people advise me to do so, not because I really know the reason why.
Thanks

I don't know the brand for the tants, nor the other caps for that matter.

Regarding the poly caps, the only ones used which I am familiar with (since my "Neve" experience is with the TNC preamps mainly) are those used for HF stability by adding feedback at higher frequencies. Either way, from what I remember, all of the caps bar the large electros are in the signal path and arguably will have a cumulative effect on the audio. I don't personally get too anal about it, but sticking to the right type is probably a good idea if you are aiming to sound more original; even if you don't think you like tantalums I suppose... Depends what you're aiming for.

IMHO this circuit sounds better with NO tants.  Use quality electrolytics instead.  Try it both ways and see for yourself.

EDIT: Roddy is right about all the caps being in the signal path and affecting the sound.  Even the big electros effect the sound.  (Bigger == more low end.)

It's a robust circuit and sounds good no matter what you throw at it.

More about the tants.  Tants seem to make the high end a bit tighter, pinched, brighter, sharper, some say spitty...  Electros instead of tants give a more relaxed, clean, gorgeous sound, IMHO.  Try it yourself, as both will sound good and everyone has different tastes.  It's a musical circuit. 

I also agree with Tantalums vs the electrolytics. One thing I wonder about is how much the placement of the components will affect the audio. If I stray from the original layout would I maybe encounter problems? Sorry if this hijacks, the thought just came up.

Jim

I believe the allen bradley cabon comp type resistors take ESD better than other types, due to their internal structure.  The resistive material in metal film and wire wound resitors are shaped like a helix and it is easier for arcing to occur internally.  That protection comes at the cost of higher noise, tolerance, resistance stability, and reliability.   

Tommy,
Those are really interesting observations on the tants vs. electros. I must say that for me, any Neve pre based on the BA283 input stage sounds consistently "warm" and even at times lacking mids and dare I say, "muddy" . Especially when you stack tracks together that you recorded through the Neve with.
I used to own 2 x 1066 EQ's and that was part of the front end to my DAW for quite a while, and when I would track a song through the 1066's (usually I bypassed the EQ) I would find myself having to do some serious, surgical EQ'ing at the mix down stage due to all of the mud build up. Don't get me wrong..... I love the Neve sound. It's just that my experience has been that they generally lack a lot of top end as well as mids. BTW, all of the gear I speak of had their original BA283 cards with the typical tants, and other caps in their usual place.
So basically I'm interested in the swapping tant for electro mod and the changes it creates sonically. I honestly have never heard of Neve's being described as having that kind of harsh tone. YMMV.

Lots of opinions of how to best dress this circuit.  Some thoughts for those who wish to experiment:

1) Electrolytics will indeed 'clean up' the sound.  The tants give an edgier yet less transparent quality to the circuit.  I've heard some opinions that electros make it more boring, but some folks appreciate the reduced color.  I have uses for both, though I personally prefer the tants.

2) If you're using an original channel module with eq, you may have noticed that it sounds both edgier AND duller with the eq engaged, even when the bands themselves are switched to "OFF."  This is because a) the eq circuit introduces 2 more amps that also have tants as stock (hence additional 'edge') and b) these amps have a 47pF polystyrene cap the rolls off the highs fairly dramatically near 20k (dull -- lacking 'air').  Pulling these styrenes out completely (C11 and C19 on the BA284) or dropping them to 10pF or so, will restore the lost HF when the eq is engaged.

3) The traditional output transformers (original LO1166's or modern Carnhill versions) also have a bulkiness to the sound that, as has been stated elsewhere in this thread, tends to be a bit much with overdub after overdub -- lots of mush to work through in mixing.  I find the Sowter replacements to be a wonderful fix for this.  They have big, clear tone without the muddiness.  For single tracks they're definitely clearer (which isn't generally the reason people love old Neve's, BTW).  I prefer a stock Neve tone for critical tracks that need to punch through the mix without lots of processing, but for lots of stacking I think the Sowters are the way to go (JLM's gapped output looks like it might be cleaner as well, but I haven't tried one personally, so I can't comment from experience).

Carry on.

JC

sine_wave said:

And about the 2N3055... I read a comment from Geoff Tanner how these should only be Motarola or Newmarket (never heard of the latter), otherwise sound may suffer. What do you think?

Regards,
John

Click to expand...

I have recently built a 1290 clone which sounds great, Dare I say perfect for my tastes. Unfortunatly I am yet to compare to an original but I built this with TIP 41 transistor instead of 2N3055 which is apparently what the Great River pre's use as well. It's supposed to be cleaner sounding.

not much to add except that JLM also uses a TIP transistor in the micro 1290. I've been meaning to get some to try since I'm still only about 80% on my 1290s...

about the lytic instead of tants, you would just get regular lytics (polarized) right?  For those that have heard the difference did you use run of the mill lytics or some kind of higher end stuff (nichicon, elna, etc), and did this make a difference?

Along with Bluzzi, I am also wondering about layout. Can you run into problems straying from the original cards' layouts?

As far as the 283 and the 284 circuits I have made mine almost exactly as original on my 1084 layout. It was easy to do that so out of superstition I kept them that way. Its the EQ section that I am more concerned with due to the nature of the parts I am using.

If you are re-doing the amps though I think you can get away with a lot. Just keep away from too many parallel traces and keep them a certain distance. Also the originals had no ground plane so newer ones may actually end up being a tad less noisy if you get one on there.

Also if you are making your own from scratch watch out because I found one or two layouts out there that have errors! Always go by the schematic!

JC, I forgot about the lower cap values for C9 and C11 (I think I saw it at G. Tanner's site IIRC), thanks for reminding me. I had 33pf in mind but I will try 10pf as well.

Jim

I'm using all Panasonic carbon film 1/2 watts for the amps...and 1/4 watts for the switch. Metal film on the rails. I have a good feeling about the Panasonic's(modern carbon films)...and at 8 channels is considerably more affordable.

http://www.panasonic.com/industrial/components/pdf/aoa0000ce12.pdf

For electro's i went with Vishay BC axials.

For tant's, i went with all Vishay 138 AML series and Tantalex series axials.
I don't mind spending the dough here.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=4188PHCT-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=718-1437-1-ND

Original Motorola 3055's...

The resistors used in the Neve silicon transistor based circuits are metal film, which was the only style offering a 2% tolerance.  The germanium based boards I have worked on have carbon 5% IIRC.
Mike
PS: If you search around here there was someone who cut some MOT 2n3055's in half to show how different they can be within the same batch.  Would not hurt to slice open a TIP vs MOT and have a look. . .

desol, cool component choices. Keep us updated on your build please. I think the Vishay/BC electro's are a must for anyone who likes to stay close to the original recipe. Besides, I've always loved the way those old blue Philips looked. You're using original Moto 2N3055's? If you have any extra (even 1) or know of a source for oldie 2N3055's either from Motorola or Newmarket please PM me.

-John

The talk about what 2N3055 you suppose to take, is the one that has verylow hfe. Otherwise  You get spikes or oscillating on strong output-levels.Normally begins at around +19 or so.
There have been or still are some 2N3055 made with label "MOT" but are cloones made from somebody unknown. The problems, with some, are that they cant take the right W.But that shouldnt be any problem within the 283.
Cheers Bo