Spectrasonics 610 (and clone info)

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I can't imagine why someone would want to clone one of these.

I"ve owned 5 of them(still have the best 2 which SpectraSonics rebuilt for me) I got them for $50 each. They are very cool for what they do but they are more of an effect than anything else, really gritty, they overload really easy but they can really push some thing forward in the mix as well. I like them for snare drum occasionally and for dirtying up a hammond organ even more than it was to begin with. Sometimes they're just the thing for bass as well.

But it would be an awful lot of work to clone something that is so limited in use.
 
[quote author="Twist Turner"]I can't imagine why someone would want to clone one of these.[/quote]

Well, there's a couple ways to answer that...

A) Because $50 is the right price for "something that is so limited in use", and $2k is not?

B) Tchad Blake

Leigh
 
Has anybody tried swapping out the input transformer, that might be a good start? If someone doesn't do it soon, I may pop one of mine open and try it.

Honestly I've got about $250 each in mine after the rebuild and honestly I think that's about all their worth for what they do. However if they sound better with a better input trans. maybe it's worth pursuing.
 
does anyone still have a copy of the pdf's Ed provided on the first page? The links are down, unfortunately.

One of my two spectrasonics 610 compressors is causing trouble and it is not one of the 601, 603 or 101 cards, already checked that. It has very little gain and the B+ is a little off at 25,4 V.

thanks, Marten
 
I just repaired one of these and blogged a bit about it:
http://electricwestern.com/weblog/?p=199

My simple observations about these technically are that they require a little attention if they're older and used (Anything with 10-40 years of use does). After I refurbed this unit it sounded 10x better.

It should not have hum at all - check the large filter capacitor. Also be sure to connect it properly with star grounding. I've seen a lot of people connect the grounds wrong (the 610 hates this - refer to their website for hookup info and grounding advice).

It might be crazy to clone these. I felt a little crazy doing the repairs I performed (especially since spectrasonics does not provide me with schematics, but that shouldn't stop anyone with good experience). The 610 is a bit idiosyncratic, and I doubt that it would be worth cloning something this quirky. Better to leave the "spectrasonics style" up to spectrasonics I think. If they go extinct, then maybe a clone would be in order, but for now, I wouldn't do it.

Yes, some of the lows and some of the highs are attenuated. I verified this by pulsing the input with a 2V square wave. The compressor rounds-off the leading edge as it "kicks" to minimize the sonic impact. However, it does respond to frequency well below 20Hz, so it's not blocking the low frequencies.

The attack time is indeed FAST. On a hard compression setting I like, I measured about 1 microsecond of attack when hit with a 2V pulse from a function generator.

IT REALLY DOES NEED TO WARM UP. Give it a half hour or more.

On the older units the audio path is usually much more impressive than the metering circuits. Generally calibrating the meters is pretty easy, but they're tweaky. The threshold lamp doesn't really read properly until the unit has been warmed up, and the meter usually drifts a dB or two from cold to warmed up. The meters do tell you what's going on, in a general sense, though. Only an oscilloscope can show you what's happening at 100 nanoseconds to 2 microseconds, though.

They're fun. They're not for everyone. It sounded awesome on some classic metal guitar tracks a client brought in. But, I would hardly use it on everything. For a maximum volume limiter it's a good option. I don't feel it's very good for anything subtle, though.

Finally, I didn't buy this unit, so I can't comment on cost. The studio owner in this case LOVES these, so it's worth a lot to him. It may not be worth so much to others.

I guess the final evaluation is: The 610 is very unique that's it's strength and weakness. It doesn't even resemble most dynamics processors of the era, so if you really know you want a 610, get it. If you really want an LA-2A or an all-purpose compressor or limiter, maybe you should think twice.

Oh, and feel free to send me an email if you need advice on calibrating these puppies. We didn't want to send it out to Utah, nor did we need to.

Lorin

P.S. On the 603A card, the metering trimmers are: Top - scale in "GR" setting. Middle - bias of VU meter. Bottom - sensitivity of "threshold" indicator & associated metering.

 
FredForssell said:
The orginal 610 used Triad A-67J (or 65) input transformers and an HS-66 output transformer.  While the HS-66 isn't too bad, the A-67/65J sucked big-time IMO.  That could be part of the HPF sound someone mentioned earilier.

It also used a really nice API-361 VU meter (that cost a fortune) and the SS 101 card which used +24 VDC rail.  That card was later replaced in other SS designs with the SS 110 card which used +/- 24 VDC rails. But if I remember correctly each of these cards had 604 ohm input impedances due to the fact that they used grounded base input stages. The single-ended power supply and low input impedance mean one needs to use large value caps for inter-stage coupling.  That is not something that can change if you use the SS 101 or 110 cards, so I'd look at using something other the SS amplifiers.

Basically, if I were going to make a 610 clone, I wouldn't.  I'd make it with the 601 and 603 cards (good meter tracking vs ratio setting), a good output/gain make-up amp (guess what I'd use), and better transformers on the input and output.  And I'd try to DC couple it from input xformer to output xformer.  But then again, I'd get rid of the input transformer and used a balanced to single-ended input stage. That's me.

I think it would be interesting to see what that sounded like.  I actually liked the way the 610 worked but not how it sounded... so much. Because it has the ability to work at such high slope ratios (100:1, if I remember correctly) people tended to have trouble setting it up properly. Typically they ended up saying it "pumped" too much.  Go figure.

Fred Forssell is an expert and I certainly am not, and I certainly can't argue with someone with such vast experience.
However, Just a note on the transformers used in the old Spectra Sonics 610's. These were the same input and output trannies and preamp cards that were used in
the Spectra Sonics consoles on which countless albums ( including Led Zeppelin III ) were recorded and mixed. The output transformers (HS-66) are also
essentially the same as the HS-56's used in Pultec EQ's. So I guess whether changing the transformers would make them better or not might depend on what
one's interpretation of better is. The A67-j transformers do roll off heavily at 15k, but they were used in the consoles too.
So anyway I was wondering if the new 610's Spectra Sonics are selling still use these old transformers or have they changed to something else?
So electricwestern, I was wondering about the one you worked on. What did it use? 
 
YES, I agree. If I wanted to roll my own, I would really use the Spectrasonics cards, as you say. They're not too pricey, either...

Transformers:

That 610 one had a Triad A-67J and the HS-66. This unit is early-ish, but after they changed knobs and started making the smoked glass VU meter, (which was BROKEN IN HALF on this one)! I'm no 610 expert or historian, so I'm not sure when and how things changed. Maybe others have this info.

The transformers are nice and classic, in my opinion. They are rather responsible for the "tone" of the unit I think. Like many Neve transformers they have color and are NOT flat across 100% of the audio spectrum. If I put nice bright Cinemags in one of these, I think it would sound WAY TOO CRISP. A colorful transformer is often a real good thing -- but it can make a given unit a "one trick pony". However, for artists that want a darker, 70s styled tone for rock and roll, this is a good box. I would never record a classical violin through it, though. I would never record a classical violin performance through a neve input these days either...

As with ANYTHING, it's about personal taste. I'm happy that this compressor is in the studio I use, though, as many of my clients want this Spectrasonics 610 sound. If you have a client that says "make it as loud as possible", this is a good tool. 

Indeed, when I put a 1 to 2V (600ohm) square impulse into the input, you could see the transformer react and slew the wave at the input and the output. I'd say that this feature augments the design. If the transformers didn't mellow this thing out, you'd probably hear some pretty harsh switching. It also wouldn't sound "vintage" -- but that's a whole different discussion.

Overall:

As far as "pumping too much" goes, I don't see that as an issue if its set properly, and one realizes it is a LIMITER - a good "squash box". If you're trying for gentle, transparent compression this might be the wrong unit.

Lorin

 
 
A few years late to the party.  I agree with the previous posts.  I find the 610 is unique.  Not good in every situation, but can be my go-to in some situations, those usually being drums and bass.  I have calibrated my pair numerous times.  My only complaint is, these two do not like to work together (stereo).  Yes, I have the link module. 
 

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Given the amount of circuitry involved (not a tiny amount by any means, but feasible to put on one board) I have been thinking about thinking about making a clone. Has anyone done this before?

Thanks for the schematics Ed :)


drew
www.toothpastefordinner.com
Do you still have the schematics for this unit? The links before your posting are now dead and go nowhere. I would be interested in receiving -- any and all -- Spectra-Sonics schematics that you might have. I have more than enough capable CAD-design software to take your old schematics and create all-new CAD-schematics and PCB-layouts!!! That's what I do!!! Let me know, OK??? THANKS.
 
Do you still have the schematics for this unit? The links before your posting are now dead and go nowhere. I would be interested in receiving -- any and all -- Spectra-Sonics schematics that you might have. I have more than enough capable CAD-design software to take your old schematics and create all-new CAD-schematics and PCB-layouts!!! That's what I do!!! Let me know, OK??? THANKS.
Would love for someone to recreate those cards. The schematics are here: https://groupdiy.com/threads/spectrasonics.45521/#post-570251
 
Would love for someone to recreate those cards. The schematics are here: https://groupdiy.com/threads/spectrasonics.45521/#post-570251
THANKS!!! -- I already have downloaded all of those schematics into a separate "Spectra-Sonics" folder on my hard-drive. Now.....do you or anyone have any -- detailed -- mechanical data and/or dimensions of the original cards? That would help immensely.

For me personally, I would probably design a whole new and different type of PCB to fit within a 1U rack-chassis. But, if someone wanted an exact clone of the original PCBs, then I would need either highly-detailed mechanical dimensions or someone would need to physically mail me an actual Spectra-Sonics PCB so I could "Reverse-Engineer" it. As an example, a few years ago some guy down in Florida had bought an original 1974 API mixing-console that he wanted to restore and he had mailed to me one each of the PCBs that were inside. He wanted me to exactly "Reverse-Engineer" the original PCBs so he could then have fabricated exact "New/Old" PCBs for his API mixing-console restoration project. And, even though I could have made some easy routing improvements about the layout, he wanted the PCB routing to exactly mimic all of the originals. I get it. Anyone? Bueller? Bueller???

/
 
THANKS!!! -- I already have downloaded all of those schematics into a separate "Spectra-Sonics" folder on my hard-drive. Now.....do you or anyone have any -- detailed -- mechanical data and/or dimensions of the original cards? That would help immensely.

For me personally, I would probably design a whole new and different type of PCB to fit within a 1U rack-chassis. But, if someone wanted an exact clone of the original PCBs, then I would need either highly-detailed mechanical dimensions or someone would need to physically mail me an actual Spectra-Sonics PCB so I could "Reverse-Engineer" it. As an example, a few years ago some guy down in Florida had bought an original 1974 API mixing-console that he wanted to restore and he had mailed to me one each of the PCBs that were inside. He wanted me to exactly "Reverse-Engineer" the original PCBs so he could then have fabricated exact "New/Old" PCBs for his API mixing-console restoration project. And, even though I could have made some easy routing improvements about the layout, he wanted the PCB routing to exactly mimic all of the originals. I get it. Anyone? Bueller? Bueller???

/
No sorry. There are some clear pics of the original cards here, but of course you can only see the routing of the bottom card, not the top one.
TBH i would prefer if a potential remake would be 1 pcb with the 601 and 603 together (and maybe even the 101 output card as well, although being able to connect it to whatever output amp available is also nice i guess)
 
Just let us start to recreate a pcb, You can also suggest to replace the front discrete amp with an opamp, lunchbox and so on.
But with the info we have we can try to copy the idea esp. of the gainreduction and than later see how we are going to implement it. I'm willing to help on this. What we need is:
-which free pcb software and which pcb service do you recommend taking in to account that I'm from europe. I've done a bunch of pcb's in the past or if somebody is willing to do the work I'm willing to check it or help where I'm needed.
-Who is willing to do a Spice model? Something we are gonna need for shure. I can do that, but I've never done that before. I will need somebody who wants to look over my shoulders.
-Who has a physical unit (preferable a later adission) and is willing to make pictures, make audiofiles,...?
 
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Just let us start to recreate a pcb, You can also suggest to replace the front discrete amp with an opamp, lunchbox and so on.
But with the info we have we can try to copy the idea esp. of the gainreduction and than later see how we are going to implement it. I'm willing to help on this. What we need is:
-which free pcb software and which pcb service do you recommend taking in to account that I'm from europe. I've done a bunch of pcb's in the past or if somebody is willing to do the work I'm willing to check it or help where I'm needed.
-Who is willing to do a Spice model? Something we are gonna need for shure. I can do that, but I've never done that before. I will need somebody who wants to look over my shoulders.
-Who has a physical unit (preferable a later adission) and is willing to make pictures, make audiofiles,...?
[which free pcb software and which pcb service do you recommend taking in to account that I'm from europe] -- KiCAD 6.0 is all the rage these days and it is a European-based -- FREE -- PCB design software program. You can download it from here:

https://www.kicad.org
I am also more than willing to design any PCBs for a "Spectra-Sonics" project, although I am merely only a beginner at designing PCBs, since I only have 40-years of experience designing PCBs for defense contractors, medical electronics firms, "RF/microwave" companies, video electronics corporations and others. My experience designing 12-layer PCBs for NASA probably wouldn't apply here either, you think???

I have the full-blown ALTIUM Designer 2022, CADENCE/OrCAD "PCB Editor" Release 17.4 and the KiCAD 6.0 PCB Design programs all loaded onto my home CAD-workstation and ready to start designing some PCBs for "something"!!! (NOTE: The ALTIUM and the CADENCE/OrCAD programs were "NOT" -- FREE -- and cost me a "pretty penny" (or, Euro)!!!

Does anyone have any detailed mechanical dimensions of the Spectra-Sonics PCBs, including the radii on either side of the edge connector fingers? I have spent hours searching for the mechanical dimensions of these types of PCBs to no avail. ANYONE??? I have been reluctantly considering buying a Spectra-Sonics card on eBay just to physically measure and "Reverse-Engineer" it so I would be able to accurately recreate a "New/Old" PCB layout as I have already done with some 1974 API mixing console PCBs. There has to be some kind of a document somewhere that someone has that shows all of the mechanical details of these cards. And, I certainly can't trust measuring anything/something from an online photograph!!!

[Something we are gonna need for shure] -- In this instance the word is spelled "sure". The word "Shure" is a US-based microphone company. You can check them out here:

www.shure.com

Well.....that's it for now!!!

/
 

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