fairchild 660

[bennyboy]

i used one overseas and loved the dam thing

i will never be able to aford one so im gona build one

i started acumulating drawings and components lists but there are a few things that are are a bit grey

i know this is a big ask but would any one on this forum have one or know of any one that would mind me haveing a look at theres
to make some notes

are there any of these in oz

[harry]

Hey Benny Boy -

check out www.groupdiy.com if you haven't done so already - there is a project for this unit on there right now.

the schematics and pcb layout iare not available on the site but you get paper copies of it when you order a set of pcbs..

they are also making custom rack cases to go with it and custom power transformers as well!


looks very well organised and easy to put together.

i'll get around to it eventually - let us know how you go

[rick]

there are three in oz i know of probably a couple that i dont know of.
and no one is gonna let you "have a look inside"
i think Rob squire would be worth paying some beer money to talk you through the realities of such a FAIRCHILD build over the phone
he has had more fairchild comps on the repair desk then anybody in the country
- it would be a long conversation i am sure so dont expect to pick his brains without filling his fridge... err wallet

[bennyboy]

i have found that to be the case rick in oz (and i dont blam them either)

abbey rd let me have a look at theres while i was over there and i made a lot of notes

there is always something u miss

and i will give rob a call next week if he dosnt mind

[no-fi]

so... it seems that group DIY 660 project is going ahead.


there's a buy thread for the PCBs now
http://www.prodigy-pro.com/forum/viewtopic.php?t=28175

I got excited and ordered a stereo kit.
:-)

anyone else going in on this? It looks much more of an "interesting" task to get the bits for than the GSSL was.

[no-fi]

...nobody?

aaah well.
looks like I'll be going it alone then...
:-)

[Barney Loveland]

Hi there, i've ordered my boards so i'm in to. Also ordered the Elma switches. But i think i need to clear my bench before then, have a dual LA2A in the works and a dual 1176. Just need some time, now if i could buy that on the internet??

BL

[no-fi]

yeah I guess I should jump on all the "hard part" group buy threads for it that I can, too....

I'm wondering what's the best (cheapest!!) thing to do in Australia for sourcing the tubes. I've never had to buy tubes before... or audio transformers...
:-)

[Barney Loveland]

I believe this project is built around Edcor transformers which won't break the bank luckily. Tubes, try ebay, or http://www.retrovox.com.au/ Or Evatco.com.au there are others but i'll have t lok them up.

[no-fi]

yeah... already looked at audio transformers. Assuming private buyers can just buy 8 from edcor, and shipping isn't nuts, it'll be OK - at $13 each, the raw price is just over $100 for all 8.

Thanks heaps for the links to local tube sellers! Looking up the tubes, seems they're not so massively expensive either, and if there's a problem with getting them, there's a few equivalents available to the listed numbers.

I expect to get all tubes and audio transformers and wima caps for around $350.

The power transformer they're ordering looks a bit of a hassle to get over here, though... I'm watching to see what happens with that, but I don't expect I'll bother with the one power transformer for everything. I hope to be able to sort the PSU with a couple of locally sourced torroids.

Those switches are pretty expensive, but!!! I'm half tempted to go for a small bunch (maybe 10?) of high tolerance dual pots, and just try out measuring them all with a multimeter in a bunch of different positions and see if I can pick the best 4... See if that will work, before I go in for another 140 euro! That distortion in the sample was pretty bad, but then the guy who did that said it was some beat up & dirty old 70s pot he had lying about. I'm sure modern high tolerance pots can do a bit better than that! at the very least, even if I go for the switches later, I'm spreading out the expense over a longer time.
:-)

...poor man's 660? I'm going to have the ghetto man's 660.


this is fun!

[rob]

is there a schematic for this thing around? I couldn't find anything on the lab...and the little info I found tended to suggest that this compressor is so far from being a 660, that calling it a 660 is pretty weird

Rob

[no-fi]

There's no schematics online. They seem to want to reduce design theft, (at least for the first run!!) Only people who order the board sets get them. Which is kinda funny as once the schematics ship, and what I know of human nature, they'll be scanned and up everywhere. (not by me though, I tend to respect people when they tell me not to share things I'm told in confidence)

Apparently it's the same basic concept as a 660... as in, the fundamental gain reduction mechanism that apparently the 660 and 1 or 2 other things use, but nothing else does... but I wouldn't know, cause I am not a hi end studio guy and have never even seen a 660, let alone know what it's meant to do or how it's meant to work. I just liked the squashed sound they got by running a piano recording through a pair of them set to squish (minus the distortion on one channel which was due to very badly balanced diff-stage biassing in that prototype, apparently?) and I like the idea of doing something compressor-y with valves and transformers. Probably also getting caught up in hype, but that's OK sometimes.

As for how close it is to a real 660.... It's not the original parts - it has 4 valves (2 x 2BC8 and 2 x 5687) and 4 edcor transformers (10kR:600R) per channel. And the PSU will be nothing like the original - it has diodes/regulators, etc. A BOM is coming this week, so people will be able to see exactly what's in there, but not how it's connected.

I think it does sound kinda funny that he's calling it a 660, now you mention it. But because I don't really know what a 660 even is, it's not such an issue for me.

[Barney Loveland]

From what I can see I think it is quite loosely based on the idea. There is definitely no 20watt class A tube amp in there, it seems to be a regulator for that part of the circuit. The BOM might help give an idea or what for the boards and schematic.

[rob]

perhaps very loosely based on the idea, in fact so loose that lets just call it another vari-mu limiter.

Big thumbs up for designing a vari-mu, bigger thumbs up for making it available for people to get their hands all hot and sweaty with the soldering iron. BUT why piggy back it onto the Fairchild's good name? This is something i don't get, and manufacturers not just DIY guys do this. It's like they don't have the balls to say "we surveyed the tech history, took it all on board, did our own original R+D and here is our new product...the XYZ".....And don't mention Neve, Fairchild, EMI, RCA, EQP, Pacifica....blah blah blah

Oh well i just hope that all the seemingly squillions of DIYers ordering this kit don't get their handy engravers out and scratch Fairchild 660 on the front panel. And that they dont even think for a minute that what they have in their benches is necessarily anything like a Fairchild in performance or function.....who knows it might be better.....

Rob

[Barney Loveland]

Here here!!! I often wonder about this too. I have great respect for the classics, there is much to be learned. But for one the technology now is different therefore things can be made better, ie quieter/smaller etc. I have and love a few Neves, BUT they are noisy by todays standards!! So like Rob said why not build on what's been before and tell it like it is. I and Gavin Pearce have a High Voltage FET pre in the works which is great but how do we market in this day of people wanting the XYZ classics?? Hmm, sorry a bit off topic.

[wez]

but how do we market in this day of people wanting the XYZ classics??

i'm tellin' ya barney, when you've solved that one you'll be well on your way. the rest is just thoughtful design and neat soldering ;-)

[davemc]

Yes I agree Rob, Plugins are the worst for this. I have a crap EQ plugin although I put a GUI of a NEVE 1073 and call it a Neve.
How many plugins do you see EQ and Compressor wise now just released for what they do with out presets of emulations.

[heathen]

Yes I agree Rob, Plugins are the worst for this. I have a crap EQ plugin although I put a GUI of a NEVE 1073 and call it a Neve.
How many plugins do you see EQ and Compressor wise now just released for what they do with out presets of emulations.

They sure are, hey have you heard the waves v series emulations, ummm they make noise, I'm not joking. :( ssssssssssssssssssssssssssseriously.

Sorry for going OT.

[no-fi]

heh.. putting it that way - I'm lucky I'm not a proper studio guy, or this whole "660" conversation would piss me off. as a synth nerd, I always get annoyed with software "808s" and "moogs" (but I quite like software and am more than happy to try software that does different and interesting things... )

I wonder what I'd think of a "poor man's minimoog" DIY project that used minimum parts, and only adhered to the basic concept of the circuits, but wasn't anything like the schematics, letalone the same parts?

STILL! it's got to be the cheapest vari-mu compressor I'll ever get my hands on, so I'm still interested.

[bennyboy]

ive started (but losing heart real quick)



still after some tx specs (there is a lot of rubbish on the net regarding these)


but getting there slowly ive managed to acumulate in london
some original blue a1 drawings a few manuals and a few little microfish's that soposedly has drawings and specs (yet to work out or find some one with the machine to read them)

so far i have lernt a lot about its design
and i guess im on my own with this one

[no-fi]

so far i have lernt a lot about its design
and i guess im on my own with this one

There are definately people out there talking about doing proper clones, and a bit of chatting about it on group diy, but nowhere near as much chatting about it as for the poormans 660.

it may be worth trawling about and emailing the people directly who've talked about cloning it? see how they went, and what happened?

[no-fi]

hey barney:
how are you going with yours? any more things lined up?

I'm very interested in sorting out the power transformer. Are you buying one from US or EU group buys?

I'm half tempted to do the power transformer with 3 separate locally sourced torroids, (a +/15v one, a 9v one... one of these overspecced by 30VA, then a 30VA transformer of the right voltage wired backwards to go back to 240) though that's not going to be particularly space efficient or cost effective....

[Barney Loveland]

I'm going to contact Tortech.com.au with the specs, so if anyone else is interested post here or pm me. There is also another guy i'm going to get a quote from but they aren't toroids. Other than that haven't sorted any more parts.

[rob]

what are you planning to use for tubes? Are you planning to go with the 6386 tube as used in the fairchild?

Rob

[Chris H]

These are worth a look for anyone thinking of building the 660:
http://tubeequipment.com/

there are some great pics of the construction in the "under the hood ,photo's link and the more photos link.

here are a few words about his approach from a post of his on another forum.


It uses a 670 circuit as its basis and that implies using a big audio power amp to drive the sidechain, as you know.
We are using 6BA6's as triodes, which mimic the plate curves of the elusive 6386's and we are using the ubiquitous 6BQ5's as sidechain outputs. Th idea being to have parts available in 20 years, hopefully.

Also, the Sowter input and output transformers sound more transparent than the original UTC's. This ends up giving you the compression effect of a 670 without the rolloff and fog-factor that is not always appropriate for every situation.

I do, however, build them with the original iron, when we can find them, and in fact, are completing 2 units now with the original UTC transformers.
Different strokes.
If I could get the extra bass mojo of the UTC's and the transparency of the Sowters, I'd die a happy man. Those who know better say I'm fighting physics, lol. So what iron goes in matters all.
Have fun!

[no-fi]

a big difference with the poorman (I just can't call it a 660 anymore...) to the fairchild, is there's way less tubes in the circuit. Only a total of 4 tubes/channel. fairchild is 10 tubes/channel, from the schematics I see.

so I guess the amplifier architecture is going to be a bit different, and maybe the 6386 isn't going to be a drop in upgrade for the poorman.... I guess no-one will know until the actual schematic is sent out with the PCBs.

[Barney Loveland]

Umm I think 6386's are going to be a little cost prohibitive unless you have a stash that you know of hidden in the hills of Adelaide?? So will probably go with what the designer has suggested.

[bennyboy]

i was going to give these a try first


http://www.tubedepot.com/nos-6386.html

[bennyboy]

ROB can you get these if so were i have been looking
if so how much? :)

i was going to give these a try first
http://www.tubedepot.com/nos-6386.html

or iwas going to try and change things around and come up with some thing and use
some thing like 2X 6BJ6's then im reinventing the wheel

[Barney Loveland]

It says they're out of stock. Do an ebay search for what price they are really going for!!!! Yikes?