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General Discussions => The Lab => Topic started by: raysolinski on November 16, 2005, 01:25:38 PM

Title: Racking Spectra Sonics 101
Post by: raysolinski on November 16, 2005, 01:25:38 PM
Hey All,
I will be racking a 101 I bought here in the black market...anyone have any info on this? I hear the feedback circuitry can be touchy....can you drive an output attenuator to control the level? ..any info would be helpful at this point :)

Ray
Title: Racking Spectra Sonics 101
Post by: matta on November 17, 2005, 03:39:48 AM
Hi Ray,

I?ve also got some 101?s on order.

Below is all the information I have gathered while doing my own research.
Most of it was gained from posts from the VERY knowledgeable Fred Forssell, who
knows ALOT about these pres and hopefully will jump in with further info.

The 101?s is a single ended +24VDC pre card, later replaced with the 110,
which is a Bi-polar Pre design (using a +24VDC/-24VDC configuration) and
inherently the 110 has a bit more headroom. The 101 was used all over the
Spectra Sonics desk in various rolls, including the famous 610 compressor.

For me it seems the 101 is to Spectra Sonics what the BA283AV is to Neve.

The pin out configuration on the 101, to my knowledge is as follows:

Pins 1,2,3 = Not Connected
Pin 4 = Input (+)
Pin 5 = Input (-)
Pin 6 = Ground
Pin 7 = Output (+)
Pin 8 = +24V
Pin 9 = Feedback out
Pin 10 = Feedback point for gain set resistor (feedback return)

You are correct in saying that it can be ?temperamental? with the gain
staging.

Fred words were:

Quote
I think you can get a limited adjustment range before the amp becomes unstable. From memory, it's pretty touchy.


The gain set resistor is connected between pins 9 and 10. The
following resistance values were give by Fred for the 110 cards, I?m not
sure how they differ from the 101, if at all.

40 dB gain Rf= 10.7k
45 dB gain Rf = 20k
50 dB gain Rf = 42.2k

The Input impedance of the 110 card is FIXED at 600 ohms (it's a grounded
base input amplifier) and the feedback return impedance is 100 ohms.

The cards originally used the Triad A-67j transformers as input transformers
and the HS (forget the model no) on output.

I would like to know how to add a pot for better gain control, this I?m
still not sure of, amongst a few other things.

Hopefully someone with more knowledge can assist you (and I) with these
questions and confirm the pin-outs.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: martthie_08 on November 17, 2005, 04:54:00 AM
maybe you can look at the schematic for the 610 compressor, it has an output pot. I have used this compressor as a preamp, it has a 1,1 : 1 setting, in which it will act as an amp, lots of gain, pretty nice! The output iron is HS-66 on my units.
Title: Racking Spectra Sonics 101
Post by: JLM Audio on November 17, 2005, 07:50:50 AM
(http://www.jlmaudio.com/Spectra%20Sonics%20110%20as%20mic%20pre.gif)

It is what I worked out for another DIYer a while ago from all the documents bits we have. So not sure if it is 100% correct. Also not sure what the difference between the 110 & 101 are but the pin out seems to be the same.

The input transformer is loaded by 620ohms on the input of the card so to match 600ohm mics properly input transformer needs to be 1:1.
Title: Racking Spectra Sonics 101
Post by: matta on November 17, 2005, 08:05:10 AM
Hi Joe,

Thanks for the great drawing. Is it possible to replace the 3 way switch
with say a 20K/22K pot to have a variable resistance and better control over
the gain (up to 45dB's)?

Thanks

Matt
Title: Racking Spectra Sonics 101
Post by: raysolinski on November 17, 2005, 09:14:51 AM
Thanks guys,
I plan to use one of your go betweens for the  mic input end Joe :)...I also have 2 different  600 ohm 1:1 transformers to try as the input iron...what kind of value are we looking at for an output pot? I did notice the similarities to the BA283..same voltage...I wonder if you loaded it up with tants if it would "go Neve" on you...

Ray
Title: Racking Spectra Sonics 101
Post by: matta on November 17, 2005, 09:40:10 AM
Ray,

There are alot of devices that run on +24VDC rails and I doubt buy swapping
out lytics for tans you would get a Neve sound. The Neve sound comes from
the design of the amp card and transformers themselves.

My reference to the similarity was more one of that fact that the BA283AV
amp card was used in different places to create different pres, channel
strips etc in the Neve consoles. In much the same way the 101 and 110?s were
used throughout the SS consoles.

Funny you mention Joe?s ?Go Between? Kits, it is exactly what I am planning
on doing with my cards.

Still unsure of what to use as an input transformer, I?ll most probably run
it unbalanced out.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: raysolinski on November 17, 2005, 09:51:06 AM
I was kidding about "going Neve"...A little poke at all the folks (NOT here!) who salivate at all things Rupert Neve  :green: ...

Ray
Title: Racking Spectra Sonics 101
Post by: JLM Audio on November 17, 2005, 05:18:52 PM
Quote
I plan to use one of your go betweens for the mic input end Joe :)...I also have 2 different 600 ohm 1:1 transformers to try as the input iron...what kind of value are we looking at for an output pot?


If you use the Go Between kit in front of the circuit above change the 22ohm resistor to 220ohm to make it a variable 20dB pad. That way the 20dB Pad will be your output level control and with the 20dB switched pad on the GO Between you can still bring the mic pre back to unity gain for rerunning line level into the pre.

Do not add a Pad to the output as it will only reduce the maximum output level which can only just do +18dBM as it is. If you are only driving 10k loads you could use a 1:2 output transformer to get +24dBM out.

Quote
Thanks for the great drawing. Is it possible to replace the 3 way switch with say a 20K/22K pot to have a variable resistance and better control over the gain (up to 45dB's)?


The answer is Yes but you want 32k of range so maybe a 50k lin pot with 100k resistor across it with 10k in series with it should work ok.
Title: Racking Spectra Sonics 101
Post by: soundguy on November 17, 2005, 05:21:09 PM
Quote from: "JLM Audio"
If you are only driving 10k loads you could use a 1:2 output transformer to get +24dBM out.


A 110 wont drive a 1:2 into a 600 ohm load, will it, only 1:1 right?

dave
Title: Racking Spectra Sonics 101
Post by: Family Hoof on November 18, 2005, 01:24:38 AM
Okay people, check out this site (http://www.technicalaudio.com/sconebar/spectra/spectra101.html) if you haven't already. John K. told me neither the 101 or 110 can drive a stepup output transformer while sounding decent, and I've read/heard this elsewhere too. According to all of the data I've seen for the 101 and 110 amp cards they were designed with the full intention of not needing transformers at all. The common-base input has inherently low input impedance, essentially set by a single resistor, and the amps in question can accept most any input impedance because it's an entirely resistive circuit. As for output, they're spec'd to drive anything 600ohms and up, unbalanced. Why would you want a step up if it's already at 600ohm? If you ask me, the fact that it doesn't want an output transformer or kind of heavy load is self-evident in that the output transistors are TO-92 or some equivalent package - there are no power devices or heatsinking at all! If you must have isolation or balancing then try something 1:1 and easy to push on both the input and/or output. In the case of the 110, the input is already actively balanced (well, kinda) with ground isolated, and doesn't want to see a transformer at all.

As for gain, the 110 datasheet says this:
open = 35dB (??)
10.7k = 40dB
20k = 45dB
42.2k = 50dB

but I recall adjusting from unity gain to about 40dB using a 10k pot and everything seemed to be working okay.
Title: Racking Spectra Sonics 101
Post by: matta on November 22, 2005, 11:21:03 AM
Hey Guys,

I've managed to get hold of the Spectra Sonics 101 Info/Sales Sheet (thanks to Doty)
and have it hosted up on my site. It has some great info and wiring advise, feel free to download it.

Spectra Sonics 101 (page one) (http://www.matt-allison.com/diy/ss101/ss101_1.jpg)
Spectra Sonics 101 (page two) (http://www.matt-allison.com/diy/ss101/ss101_2.jpg)
Spectra Sonics 101 (page three) (http://www.matt-allison.com/diy/ss101/ss101_3.jpg)  
Spectra Sonics 101 (page four) (http://www.matt-allison.com/diy/ss101/ss101_4.jpg)
Spectra Sonics 101 (page five) (http://www.matt-allison.com/diy/ss101/ss101_5.jpg)  

Here is the Schematic of the card it is actually of the 610 Compressor, which features a 101 card.

http://edanders.home.comcast.net/diy/ss_schem.pdf

I hope it is helpful.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: jamesfei on November 22, 2005, 01:58:47 PM
Hi folks. I have two SS 101 cards coming and just wanted to know what pin spacing the edge connectors are, since I'm putting an order at Digikey at the moment. I believe the pin out's are plated on both sides of the pcb? Thanks.

James
Title: Racking Spectra Sonics 101
Post by: matta on November 22, 2005, 02:27:39 PM
I'd also like to know where to get the edge connectors. Anyone know?

The cards are single sided, here is a pic

(http://www.matt-allison.com/diy/ss101/ss_101_cards.jpg)

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: Christian on November 22, 2005, 03:25:07 PM
Edge connectors are .156 spacing / 10 position. Digi-Key part number EDC306100-ND. I believe this is for solder tails they offer two models. Brand EDAC
Title: Racking Spectra Sonics 101
Post by: matta on November 22, 2005, 04:00:56 PM
Thanks Christian,

Have you racked up these before using those edge connectors? Any chance of some pics?

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: raysolinski on November 23, 2005, 01:18:53 AM
Okay, with some sleuthing and piecing together of the information here and on the data sheets from doty I got the 101 up and running (kinda slapass, no edge connector, wired a mic cable right to the tranny etc...)...it sounds really good! I have the gain hard wired at 40 db with a 20k resistor in the feedback loop. I used an input transformer from an old pm1000 module that I use for parts.and ran the output unbalanced.This thing has got a HUGE bottom end that isn't muddy at all..I did a quick, unscientific A/B with an sm81 on my takamine n-10 acoustuc guitar between my mackie vlz and the 101 and the 101 SMOKED the wackie..the vlz sounded okay but the 101 has a really nice low end, smoother mids and no brittleness to the highs..there is still a little noise/hum I need to work out of the 101. For those who are interested pin 6 is the ground..I wired all the grounds there and then to the chassis. I am using a 24 volt dc walwart that could probably use a little filtering as well in the final box...I can post some sound files later in the week if someone cares to host them for me since I currently don't have any space online to host things...

Cheers,
Ray
Title: Racking Spectra Sonics 101
Post by: matta on November 23, 2005, 02:14:12 AM
Hey Ray,

Congratulations! Glad you are up and running. I?ve got the space, so you are
most welcome to e-mail me the comparison files and I?ll host them for you
and then post the links here. My e-mail is matt(@)matt-allison.com (remove
the brackets).

Well done again, I think this resource of info will prove helpful for future
101 rackers.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: PRR on November 23, 2005, 04:08:23 PM
> designed with the full intention of not needing transformers at all.

The input is unbalanced. While I've had great results with unbalanced mikes, in hostile rooms you probably do want a 1:1 input transformer.

> The common-base input has inherently low input impedance

Actually, with feedback the emitter impedance is far over 2K, in parallel with a resistor of about 600Ω. Most mikes will be fine with that, though some say they want 1K or 2K load.

Noise level is not ultra-low (the common-base rigging has no special noise advantage in audio) but low enough for any normal studio work. Noise Figure may be as high as 4dB: you can find mike-amps that in practice will be a couple dB quieter IF your studio background noise does not mask mike/amp noise. Of course any condenser mike's noise level will be set by the head-amp, not by the console amp (unless it is incredibly bad).

Unlike many newer amps, the input noise level does not rise as gain is reduced. However minimum gain may be limited by stability. I assume that is why JLM suggests an input pad to accept today's hot mikes.

> output, they're spec'd to drive anything 600ohms and up, unbalanced.

Right. SS was consolidating racked tube-amp consoles into a more compact system, where most runs could be unbalanced. In those days we didn't have a lot of outboard processors. Unbalanced is cheaper, lighter, cleaner. Now we've turned back to balanced systems so we can patch-in outboard boxes randomly without ground-loops.

> the fact that it doesn't want an output transformer or kind of heavy load is self-evident in that the output transistors are TO-92 or some equivalent package

Actually, the TI epoxy blob will dissipate a Watt or more. But a conservative analysis of this output stage suggests 40mA max-peak and maybe 20mA low-strain. With just +24V supply, voltage is 10V peak. 10V/20mA is 500Ω minimum happy load. Any load reduces open-loop gain of this output; at 500Ω it runs maybe 80dB forward gain in the bass, less in the highs. So at high closed-loop gain and low load Z it will start to sound strained, especially in the highs. A 1:1.4 300Ω:600Ω step-up might be tolerable if you HAD to have isolation and over 10V peak, but in general 1:1 600Ω:600Ω is the limit and working no-iron is really the way it was meant to live. As JLM says, if all loads are over 10K, you could use a high-quality 1:2 2.5K:10K step-up to ensure full 19V peaks; darn few 10K inputs really need to be hit so hard. If you just like iron, use 1:1 and try a resistor in series so the amp doesn't try to damp-out all the iron-sound.
Title: Racking Spectra Sonics 101
Post by: raysolinski on November 26, 2005, 01:52:03 AM
The latest update..I got rid of the hum..it requires a ton of star grounding. Each ground thru a seperate wire to the chassis since there is no common ground that runs thru the board.I recapped the input and output coupling caps and that was a big improvement.  I played around with it some more and the low end still sounds HUGE without any mud. I ran a fender bass into it thru a di box and it was beautiful....It would be cool to mod it to squeeze a little more high end out of it but it has enough without being sharp..prolly good for mics that are a little bright (414's come to mind)....Definately a color for the crayola box :)..now to add phantom and get a front panel...

Ray
Title: Racking Spectra Sonics 101
Post by: Christian on November 26, 2005, 11:34:57 AM
Please keep the posts coming and if you could explain in a diagram regarding the grounding procedure it would be awesome. Seems easy enough, but I am about to start racking a few of these and all the visuals diagrams available would be awesome. How thick of wire for the ground, did you just stick with 22 or thicker?

     Since there is no balanced out, would the circuit of the balanced output of the SSL pre work good here using the SSM2142 if you do not want to mess with transformers?

Thank you,
Chris
Title: Racking Spectra Sonics 101
Post by: matta on November 27, 2005, 01:53:09 PM
Hey Guys,

Ray passed on his Grounding notes and drawing which I'm hosted up on my site. It is a Word Document.

Spectra Sonics 101 Grounding Scheme (http://www.matt-allison.com/diy/ss101/SS101_Grounding.doc)

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: matta on December 12, 2005, 05:38:21 PM
Hi Guys,

These clips are courtesy of Ray who has got his 101's up and running (rather envious, but my time with come!).
He managed to do a couple passes with 3 pres, the details of which are below.

The mic was a Shure KSM44 set on cardiod, no pad or bass roll off...12th fret..Guitar was a Takamine N-10
on a recording guitar stand (so the position was the
same for all three)..I tried to gain stage them equally...

Mackie VLZ (http://www.matt-allison.com/diy/ss101/Mackie%20Sample.mp3)
API 312 with Melcor (http://www.matt-allison.com/diy/ss101/API%20312%20Sample.mp3)
Spectra Sonics 101 (http://www.matt-allison.com/diy/ss101/SS%20101%20Sample.mp3)

Enjoy!

Matt
Title: Racking Spectra Sonics 101
Post by: guavatone on December 12, 2005, 06:20:43 PM
Nice, I've heard folks describe the Spectrasonics as "sweet".  Now I know what they mean.  I feel it really stands up to the API.  And good thing the Mackie is there to laugh at.

The problem is that each performance is different.  Ideally you'd want the same performance recorded to all three preamps.  I am sure someone can explain the correct way to do this.  And it would probably involve building another box. Just my 2cents.

Thanks for the samples!

OH!  ....Ray, What XFRMs did you use on the SS? in/out?
Title: Racking Spectra Sonics 101
Post by: JustinS on December 12, 2005, 09:00:50 PM
Interesting to hear... I agree though, kinda hard to make a super informed decision about what you're hearing with this kind of example - most of the differences in each sample could be attributed to how differently the snippet was played each time.  Having said that, the 101 did sounded neat - my favourite of the bunch... The API w' melcor had an interesting prescence and I have to say, the Mackie didn't suck that much(a little bit gutless)... especially after a little compressing.  What you really need is a mic splitter transformer, now that's a much more informative kind of test!

Justin
Title: Racking Spectra Sonics 101
Post by: raysolinski on December 12, 2005, 09:48:50 PM
The input and output tranny's on the SS101's are opamp labs...t-25's (?)..1:1...I didn't mean for this to be scientific in any way  :oops: ..I think the mackies are a little gutless and it really builds up in a multitrack mix.They sound okay with a track or two, or live where there is too much room noise to care..The 101's have a really pleasant high end to them...great on vox too.

Ray
Title: Racking Spectra Sonics 101
Post by: Bryson on December 13, 2005, 02:07:23 AM
The 10 pin - AMP 583417-1 is good, but a 15 pin Amphenol as used with API 312 etc. will also work fine.
(http://home.earthlink.net/~redbugg/all/AMP-EdgeConn.jpg)
Title: Racking Spectra Sonics 101
Post by: Bryson on December 13, 2005, 02:11:41 AM
(http://home.earthlink.net/~redbugg/all/SS-101-Chnl.jpg)
Title: Racking Spectra Sonics 101
Post by: matta on December 13, 2005, 02:24:29 AM
Throw someone  a bone they want your arm, LOL

As Ray said it wasn't designed as a pre shootout and even with my deafening
ears I can hear the different tonal qualities between the 2. The API seems
'Clearer, and has a nice Top End' the Spectra Sonics is 'Warm & Smooth'.

Bryson thanks for the heads up with card connectors, what si that lovely
blue thing?

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: Bryson on December 13, 2005, 05:21:31 AM
Quote from: "matta"


Bryson thanks for the heads up with card connectors, what si that lovely
blue thing?

Cheers

Matt


An MXR Mini Limiter (a real atom smasher). Click on the pic for full size.
The ten pin AMP connector came with it, but fits the 101 nicely.

The batch of 101s I got came with the 15 pin connectors.
Title: Racking Spectra Sonics 101
Post by: matta on December 13, 2005, 05:48:33 AM
Ah I see,

I've ordered some of the 10 pin ones from Digikey, I believe they fit
snuggly. That comp looks lovely. Have fun racking up the 101's. Out of
interest what is the Schematic of, a complete Spectra Sonics console?

Where did you get your 101 cards, if I can ask.

Also does anyone have an e-mail address for Spectra Sonics? I believe they
are still in business, but not making consoles, but have some old modules
around. The 501 Eq's look cool.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: guavatone on December 13, 2005, 04:22:01 PM
Doty was selling a bunch on BM.  He was selling XFMRs too,  He was parting out a console so he may have more. PM him.

PS. I didn't mean to belittle the great effort of posting these samples.  My curiousity is more the reason for posting that comment.  I do actually greatly appreciate the samples.
Title: Racking Spectra Sonics 101
Post by: matta on December 13, 2005, 04:51:11 PM
Quote
Doty was selling a bunch on BM. He was selling XFMRs too, He was parting out a console so he may have more. PM him.


Thanks Guava,

I know, I got my cards from Doty  :green:  I was just wondering about the EQ's more and just touching base with SS in general.

No worries on the samples.

Matt
Title: Racking Spectra Sonics 101
Post by: wiz1der on December 15, 2005, 02:17:58 PM
I was one of the people lucky enough to get a pair of these when Doty offered them in the black market. After Re-reading through the post a few times, I am sad to say that I am thinking about selling these. Even with the Go-between kits from JLM, I just don't see how I would wire this up. Do I need Iron? or not?  What would I use as a pot for Variable gain?

Just so many questions that without a specific "dummy" drawing, (hook this (a) up to this (b)), I think I would be lost. So I may be offering these to some lucky soul.

 :sad:
Title: Racking Spectra Sonics 101
Post by: JustinS on December 15, 2005, 03:15:20 PM
Oh... hey in my earlier post I just went straight in and criticised the validity of the test... oops first thing I should have said is thanks for putting up the samples!! (my girlfriend would have killed me for that)...

And wiz1der - you'll need iron in (either a straight 1:1 600:600 tranny, or better a 1:2 150:600 tranny), I don't think the Spectrasonics are really setup for for variable gain... most people run them with either a variable pad on the input or output.  So the way to hook these up would be xlr in -> JLM go between kit -> variable input pad -> input iron -> line amp -> optional output transformer -> xlr out.

Justin
Title: Racking Spectra Sonics 101
Post by: cwileyriser on February 14, 2006, 02:37:39 PM
I'd love to see photos or schematics of finished, racked-up 101's if anyone is so inclined - or even just info on how what you set them up with.  I'm working on some too.  I was planning to use the JLM Go Between and the JLM DI, but am not sure on transformers.  I'm hoping to be able to make a good choice the first time, so I don't spend a ton buying more than I need.

Thanks!
Title: Racking Spectra Sonics 101
Post by: matta on February 14, 2006, 04:27:48 PM
Hey Chris,

Welcome to the Forum! I've seen your virtual face over at Tape Op, and had I had the money I would have taken your Valley stuff... was drooling...

Anyways, back to your question...

Most, if not all you need is in this thread. I would def. recommend getting some of Joe's kits, they are easy to use and take out alot of the guesswork and makes for neater wiring.

RE transformers you just want to make sure it the secondaries terminate at 600 ohm's which is what the pre wants to see. You can use either a 1:1 (600:600) or even a 2:1 (150:600 ohm) transformer. Personally I used an OEP, which is made in the UK, and good value for money.

RE a pic, here is a front view of my rack, the SS101's situated on the right.

(http://www.matt-allison.com/diy/spectratone/front.jpg)

Feel free to ask more questions if you need to.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: 87w on February 14, 2006, 06:40:59 PM
Matt,

Very nice looking rack job. I've got a couple questions for you, if you don't mind my picking your brain. I just ordered a pair of these for myself and will be racking them either right before or right after I rack my Telefunken V672s, depending on which arrives first.

First off, that is a very pro looking front panel, where did you have it done?

Second, about the transformers. Did you end up using 600:600 or 150:600? I read in the manual that you posted that they reccomend using 600:600 for condensor mics and 150:600 for dyanamic mics. Have you run into any problems with this? For example, if you put in a 150:600 have you had issues running a condensor into it, or vice versa? Also, did you use an output transformer, or are you running unbalanced?

How did you resolve the gain set issue? Did you hardwire the amps at 50dB with a 42.2k resistor, and than use a variable input pad to set your level?

Anyway, the pre's look great. Thanks for posting the pic.

Sam
Title: Racking Spectra Sonics 101
Post by: cwileyriser on February 15, 2006, 01:10:17 AM
Yes, nice-looking job!  Sorry about the doofus post earlier.  I hadn't noticed that the thread was 3 pages long!  I had only read the first page....  Looking forward to getting more into this.  Thanks to all for the resources so far.
Title: Racking Spectra Sonics 101
Post by: 87w on March 01, 2006, 04:54:15 PM
Hi all,

I'm reviving this thread because I'll be racking my spectra sonics soon, and have a couple questions before I order my parts.

I'm going to use the variable input pad from Joe's drawing on page one of this thread. Should that pot be audio taper or linear?

Also, I've got a ss103 line amp card. Any ideas on what I ought to do with this? Does anybody know if the pinout is the same as the 101s?

Thanks,
Sam
Title: Racking Spectra Sonics 101
Post by: 87w on March 02, 2006, 04:03:19 PM
Bump,

Log, Linear, Anyone?

Sam
Title: Racking Spectra Sonics 101
Post by: matta on March 02, 2006, 04:11:02 PM
Hey Sam,

I'm not sure, best drop Joe an e-mail and post back. I didn't use the variable pad, I just have a Lorlin switching the resistors in the Feedback path, which is not so cool as I'm getting pops when switching.

I know Ray used a REV pot in the Feedback loop, he said this in an e-mail/PM

----
A 50k audio or log taper pot wired in reverse with a 5.5k resistor hanging off the ground side (used as a variable resistor, NOT a shunt to ground) in the feedback loop makes a really nice and smooth gain control
----

I dropped him and e-mail to get more details, I'll report back if I hear anything.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: JLM Audio on March 02, 2006, 05:40:33 PM
The pot for the variable pad should be a dual 1k log or audio taper pot.
Title: Racking Spectra Sonics 101
Post by: raysolinski on March 02, 2006, 07:55:11 PM
I used a 50k audio taper in the feedback loop with a 5 k in series so the minimum is 5k and the max 55k..a little over spec but you can watch your gain for distortion etc...Since it is in a dc feedback loop it is a little noisey when you turn it...probably better to set it at 50 db with a resistor and control the output,  or with an input pad. Not very much gain with these guys..probably best suited as intended, as a line amp, or maybe strap 2 together set at 40 db and control it with some type volume pot?

Ray
Title: Racking Spectra Sonics 101
Post by: cannikin on March 02, 2006, 09:46:28 PM
Hey Matta,

I'm starting to dive into this project and I was wonder what PSU you used.
I got 2 101 cards :grin:

I was thinking of getting one of JLMs PSU boards and the go between (of coarse). Also, What is Power trannie Rated.

In Addition, I have a 103 card -  What Could I use it for?? a DI?

thanks
Title: Racking Spectra Sonics 101
Post by: matta on March 03, 2006, 03:05:07 AM
Hey Cannikin,

I can't praise Joe's kits enough. I wired all my FETboy's off board, took about and hour or more, and alot of caution, and still managed to mess up the pad... I bought some of Joe's kits for the Spectra Sonics, had them built in 20 minutes and since it is all on one board as long as you don't mess up resistors (which is kind of hard to do) you will be up and running in no time.

RE PSU I used a converted Peter C Green Pre PSU board as I had a few lying around. But I would suggest using Joe's if you are going to order the switch kits. They 2 are easy to use and will allow you to trim down/up the rails.

I would suggest you heed Joe's advise on using a Variable input pot. Ray tried a pot, and is is scratchy because it is in  DC feedback path, and I used a Lorlin which pops and not as easily tweaked.

I'm going to be fixing my gain at say 50dB's and using a 20dB variable pad on input.

RE the 103's, I'm not familiar with them so can't comment on their use. If you wanted to add a DI I would suggest adding in Joe's DI kit which combined with the 'Go Between' will be a great combo.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: Twist Turner on March 05, 2006, 01:21:02 PM
I have a pair of these to rack as well.  Matt I really like the red knobs. Where did you get them???
Title: Racking Spectra Sonics 101
Post by: cannikin on March 21, 2006, 12:49:13 AM
Hey guys could I Use the sowter 9145 Neve Mic/Line Input
300/1k2 to 1k2/4k8. Ratio 1+1:2+2.  For the input??

Got a couple on the shelf collecting dust... :?
Title: Racking Spectra Sonics 101
Post by: matta on March 21, 2006, 10:33:20 AM
Hi Guys,

Twist, the knobs are from Small Bear Electronics (http://www.smallbearelec.com/home.html)

Cannikin, not sure the tranos will work. The board was designed to see 600R on input. So a good 1:1 at 600:600 is what you should be looking for.

I have mine wired 150:600, which seems to work well.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: cannikin on March 21, 2006, 12:50:08 PM
thanks Matta


I'm just going to use the triad HS-66 on input and a Cinemag 1:1 on the output

Cheers
Title: Racking Spectra Sonics 101
Post by: Twist Turner on March 22, 2006, 01:31:21 PM
Got a quick question for you guys.  I've got 2 Sowter 3603  600ohm to 600 ohm transformers and also a pair of Triad HS-66's coming. Which would you use on the input, which on the output and why?  I was thinking to use the Triads on the input using the 150ohm to 600 taps, and the sowter on the output, what do you think?

Oh, thanks for the knob link Matt, those Cream colored ones they have look pretty nice.
Title: Racking Spectra Sonics 101
Post by: cannikin on April 20, 2006, 11:50:20 PM
Hey Matta,

I have a couple questions about racking the 101.  I'm a little baffled on a few things.
Imagine this was a block diagram:

XLR in --
JLM go Between --
input level Pot (Have a couple DAVEN 600 Ohm) --
input transformer (triad HS66) --
101 card --
Output transformer (Cinemag 1:1) --
XLR out

Also I could do without the Input Level Pot and just use the 3way Switch to attenuate within 10dB ... Correct?

On the Triad HS66 anyone know off hand which Pin is Ground?

Thanks
Title: Racking Spectra Sonics 101
Post by: matta on April 21, 2006, 11:25:59 AM
Hey Cannikin,

Your sequence looks pretty dead on. You could indeed do away with the level pot. Something to be aware of is that when you change the level you are switching the gain resistor in the feedback path, which has some DC and I tried this with both MBB and BBM switches and still got a 'pop' doing it (not sure if it was because of the DC, just thinking aloud) so I FIXED the gain at 50dB's and then used Joe's Input Pad instead of a level pot.

So it now goes JLM, Variable Pad Pot and then transformer, and then 101 card.

This has provided the best result for my needs, it is wired so that as you turn the pot CW the pad decreases the pad till it is off when fully CW.

I'm not sure on the Triad as I used an OEP trano as my input.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: jamesfei on April 22, 2006, 12:07:44 PM
If you're mostly using the 101 as a mic pre, it's better to put the Daven (probably a Ladder or T?) on the output, before the transformer, and keep the input path as clean as possible. If the JLM has a 20db pad it'll keep the card from clipping, along with the gain adjustment switch, and the output attenuator will let you set levels precisely. Off hand I don't think the Triad has a ground pin, just ground the case via the mounting screws.

Best,

James


Quote from: "cannikin"
Hey Matta,

I have a couple questions about racking the 101.  I'm a little baffled on a few things.
Imagine this was a block diagram:

XLR in --
JLM go Between --
input level Pot (Have a couple DAVEN 600 Ohm) --
input transformer (triad HS66) --
101 card --
Output transformer (Cinemag 1:1) --
XLR out

Also I could do without the Input Level Pot and just use the 3way Switch to attenuate within 10dB ... Correct?

On the Triad HS66 anyone know off hand which Pin is Ground?

Thanks
Title: Racking Spectra Sonics 101
Post by: cannikin on April 22, 2006, 12:31:18 PM
Thanks Guys

Much appreciated...
Title: Racking Spectra Sonics 101
Post by: cannikin on May 13, 2006, 12:17:57 PM
Hey Guys,

I'm having some difficulties -- I'm stumped  :roll:

First of all Let me tell you what I have and what I'm trying to do...

JLM ac/dc (+/- 24Vdc)

Here's My Signal Chain:

XLR In
JLM Go Between (NO DI) using Jumpers
Triad A-67j Input (Wired 1:1 600 Ohm)
101 Card  
HS-66 Output ( 1:1 600 Ohm)
XLR out

Feedback Using Grayhill Switch with Resistors (10K 20K 42K) for DC Signal Ouput Gain Adjust

I'm using the layout supplied by JLM

THE ISSUE: NO Signal :mad:

I noticed that -24V (B-) is really not connected to anything on the card... Correct?  ON the Layout connection C

Next I thought Maybe I have the Transformers wired incorrectly  :?

Go Between to transformer Input Primaries - Secondaries to 101 ( D which is + and E which is Minus)

101 Card output (H -- signal output + and F -- Signal Output MInus) to Secondaries of the HS66 Primaries to XLR

I can't figure it out.......
Title: Racking Spectra Sonics 101
Post by: matta on May 13, 2006, 01:31:41 PM
Hey David,

The 101 is single ended, only needing a +24V rail, so you are right there is no -24V rail.

Let try break it down to the simplest form.

Your connections sound right on the front end, to just check things lets do a basic processes of elimination.

Can you remove your switch and for now just hard wire a 10K resistor between tab K+L.

Then run the card unbalanced out, removing the output trano, so tab H to Pin2, tab F to Pin 1 on the Output XLR, and join pin3 to pin 1.

Now we concern ourselves with the basics, which should be.

XLR In - Go Between
Go Between - Input trafo primaries
Input trafo secondaries - 101
101 - XLR Out

Just try that configuration and report back with results.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: cannikin on May 13, 2006, 02:15:11 PM
Thanks Matta..

Ok Your suggestion worked....

Getting Sound (although output is really low)

Next... ??
Title: Racking Spectra Sonics 101
Post by: matta on May 13, 2006, 02:24:48 PM
Quote
Getting Sound (although output is really low)


Hi David,

Good to hear. Just clarify the sound you are getting. Is it clear, just low output, any distortion, muffled in anyway?

Try replacing the 10K with a 42K, this should bring the volume up, and also make sure you tie Pin 1 and Pin 3 together on the Output XLR, otherwise you will loose some volume there as well.

Once done, report back.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: cannikin on May 13, 2006, 03:50:05 PM
The sound is Pretty Dirty ... Definitely not clear..

I haven't Grounded the circuit like your recommended and have not replaced the caps Yet.
Title: Racking Spectra Sonics 101
Post by: matta on May 13, 2006, 04:13:17 PM
Well the grounding is important, I've found it VERY tempremental on these cards.

I'm not famialer with the Triad's sicne I used an OEP, but I know that on the OEP I had ground the screen as well.

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: cannikin on May 13, 2006, 04:44:27 PM
Thanks Matta,
Since there is only +24 Rail.

On the JLM ac/dc you don't need the -24 Rail connected to anything.
What about the 0V rail on the Ac/dc...  Goes to the GO BETWEEN and then to Ground (if Pin 1 and 3 are tied to ground)??

Except for  + Basically everything goes to goes to ground in one way or another?
Title: Racking Spectra Sonics 101
Post by: Neeno on May 13, 2006, 05:50:43 PM
Hi David, i didn't racked my 101s yet, but one is wired inside a old case i use to check out stuff before rack it...

I'll suggest to remove the output transformer, and check it unbalanced.

If you are using the JLM psu, remember the the 0V on the JLM psu should be your star ground point. There is one of the fixing holes (the one near the 10R resistor) that shall be connected to your case, and then from the case you'll have a connection to your IEC.

I'll start from the input XLR:

- Input XLR Pin1 should be connected to the star ground (JLM PSU)
- Input XLR Pin2 and Pin3 should go to the GO BETWEEN input.
- Connect the 0V of your GO BETWEEN to the star ground
- Connect the transformer input to your GO BETWEEN output (i used 150:600)
- Connect the transformer ground to the star ground
- Connect the transformer output to your 101 input
- Connect the output of the spectrasonics to the output XLR and tie pin1 and pin3 togheter.

Hope this helps...

Quote from: "cannikin"
Thanks Matta,
Since there is only +24 Rail.

On the JLM ac/dc you don't need the -24 Rail connected to anything.
What about the 0V rail on the Ac/dc...  Goes to the GO BETWEEN and then to Ground (if Pin 1 and 3 are tied to ground)??

Except for  + Basically everything goes to goes to ground in one way or another?
Title: Racking Spectra Sonics 101
Post by: cannikin on May 19, 2006, 03:31:20 PM
Thanks Neeno and Everyone..

Ok.. I had to take a Break from this because I Blew up my JLM ac/dc by shorting the 48V rail... the LM317 Exploded and destroyed the PSU Traces

...Live and Learn....

Check it out Fellas... Finally Got it figured out!!! they sound great!

http://www.groupdiy.com/index.php?topic=184071#184071

Thanks So Much for everything
Title: Racking Spectra Sonics 101
Post by: clintrubber on May 30, 2006, 04:40:26 PM
I just finished reading the patent about that 101 circuit (3,376,515) and since it's such a compact circuit & a bit different from the rest it'd be fun to thrown one on breadboard (one day...).

Is there a complete schematic with all component values out there ? Haven't found anything like that yet.

As I understood from the patent it's all Ge-transistors except for the two NPN output devices. Which types ? (not that I expect to be able to find those, but one has to start somewhere).


Regards,

  Peter
Title: Racking Spectra Sonics 101
Post by: clintrubber on May 30, 2006, 05:46:44 PM
Quote from: "clintrubber"
I just finished reading the patent about that 101 circuit (3,376,515) and since it's such a compact circuit & a bit different from the rest it'd be fun to thrown one on breadboard (one day...).

Is there a complete schematic with all component values out there ? Haven't found anything like that yet.

As I understood from the patent it's all Ge-transistors except for the two NPN output devices. Which types ? (not that I expect to be able to find those, but one has to start somewhere).


Regards,

  Peter


edit: Ah, found the circuit-values, thanks Matt - I had already downloaded the schematic from the first page of this thread last week but hadn't really looked at it.
Everything's there  :thumb:
Title: Racking Spectra Sonics 101
Post by: clintrubber on June 01, 2006, 09:25:42 AM
Quote from: "matta"
Hey Guys,

I've managed to get hold of the Spectra Sonics 101 Info/Sales Sheet (thanks to Doty)
and have it hosted up on my site. It has some great info and wiring advise, feel free to download it.


In addition to the nice stuff that Matt found, I encountered a few more interesting downloads for 101-builders:

http://recforums.prosoundweb.com/index.php/mv/msg/9573/0/0/0/ (2 pages)

Especially:
http://www.technicalaudio.com/a2z/S/SpectraSonics/SpectraSonics_101_manual.pdf (courtesy of John Klett)

but have a look at the complete thread I'd say.

Regards,

  Peter
Title: Racking Spectra Sonics 101
Post by: cannikin on June 01, 2006, 09:34:51 AM
Hey Clint

I have been working on some sub parts for the Diodes and Transistors.

Here is the thread:

http://www.groupdiy.com/index.php?topic=15506&highlight=101

I purchased the parts I listed in the first post and put them on the board... just haven't had time to hook to transformers and test
Title: Racking Spectra Sonics 101
Post by: clintrubber on June 01, 2006, 09:47:28 AM
Quote from: "cannikin"
Hey Clint

I have been working on some sub parts for the Diodes and Transistors.

Here is the thread:

http://www.groupdiy.com/index.php?topic=15506&highlight=101

I purchased the parts I listed in the first post and put them on the board... just haven't had time to hook to transformers and test


Hi,

Yep, had seen that thread, thanks. Since the possible replacements weren't much easier to find here I'm settling for BC550 & BC560, with perhaps BC337 for the output-NPN's. Not completed yet, but I'll be reporting once done.

Bye,

  Peter
Title: Racking Spectra Sonics 101
Post by: clintrubber on June 01, 2006, 07:11:13 PM
More hello David,

As it happens I saw various differences in the component values of the previously posted schematic (earlier in this thread, 'the handdrawn one') and the one I linked to a few posts above here ('printed').

The differences concern various small differences in the resistor values, no big deal I expect; they're in essence the same, but sometimes jump to another close value in the resistorvalue-range.

But the cap in parallel with the 11k(10k7)-resistor connected to the collector of the first NPN Q1 differs more:
'handdrawn' vs 'printed': 20p vs 220p

It'll become clear from the breadboarding what the best value is, but in case someone with original 101-cards can have a look ?

Thanks,

  Peter

Note I'm not involving the schematic-topology from the patent here, that one hasn't have component values and has a slightly different topology compared with the actual 101 - cards.

And w.r.t. 'printed' I mean the version on the last but one page of that pdf; as I understood the version on the very last page is some later suggested update or something. Are you still with me ?
Title: Racking Spectra Sonics 101
Post by: cannikin on June 01, 2006, 07:27:35 PM
Its .002uf

Just measured it on the original board
Title: Racking Spectra Sonics 101
Post by: clintrubber on June 01, 2006, 07:33:05 PM
Quote from: "cannikin"
Its .002uf

Just measured it on the original board


Thanks, but  :shock:  
It gets bigger by the minute !?!   :?  :shock:  :wink:

You sure it's 2nF ? I mean, that's another ten times as much - on the first schematic I saw it was still 20pF and then 220pF.


Hey, you have original boards ? That's cool, convenient for some measurements when cloning  :thumb:

Regards,

  Peter
Title: Racking Spectra Sonics 101
Post by: clintrubber on June 02, 2006, 06:50:25 AM
And FWIW here we have the 110, so with +/-24V supply for more headroom:
http://www.technicalaudio.com/a2z/S/SpectraSonics/SpectraSonics_110A_sch.pdf

So this is the card for which JLM gave the hookup-info earlier in this thread.
So when cloning it's easy to make either a 101 or 110, but I won't really be needing the higher levels possible with the 110. A joint use of +/-24V & 48V for phantom could be considered though.

Anyone toyed around with the 101 & 110 side by side by chance ?


There's some more SpectraSonics info there, thank you Mr. Klett:
 
http://www.technicalaudio.com/a2z/S/SpectraSonics/

Regards,

  Peter
Title: Racking Spectra Sonics 101
Post by: JLM Audio on June 05, 2006, 05:46:53 AM
Yes this 110A circuit does have 2.7k input impedance so a 1:2 input transformer would work fine on the input to give 6dB more gain. Make sure you run it on the +/-24v as shown and only E & F go to 0v.
Title: Racking Spectra Sonics 101
Post by: clintrubber on June 05, 2006, 07:50:48 AM
Quote from: "JLM Audio"
Yes this 110A circuit does have 2.7k input impedance so a 1:2 input transformer would work fine on the input to give 6dB more gain. Make sure you run it on the +/-24v as shown and only E & F go to 0v.

Thanks Joe for the confirmation :thumb: Yep, will use +/-24, thanks.
 
Since I'm cloning from scratch, it sounds like the 110A would be the best way to go - more freedom w.r.t. micpre-TX-configurations.

Since from what I read I got the impression that the 600 Ohm input impedance of the 101 & 110,
even when used with a 1:1 TX, give a bit too low inp.imp, correct ?
As in 'it will do just fine, but might have been a bit more'.

Regards,

  Peter
Title: Racking Spectra Sonics 101
Post by: cannikin on June 11, 2006, 09:02:19 PM
Hey guys,

I'm racking my second pair of cards and wondering if there any way to stop the clicking sound when using a switch to change the feedback resistor?
Title: Racking Spectra Sonics 101
Post by: laitue5 on June 12, 2006, 02:13:12 AM
Do you use a ?Make Before Break? switch?
Title: Racking Spectra Sonics 101
Post by: JLM Audio on June 12, 2006, 09:13:56 AM
Quote
Since from what I read I got the impression that the 600 Ohm input impedance of the 101 & 110,
even when used with a 1:1 TX, give a bit too low inp.imp, correct ?
As in 'it will do just fine, but might have been a bit more'.

I usually like the sound of most mics with 600ohm loads except ribbons.

Quote
I'm racking my second pair of cards and wondering if there any way to stop the clicking sound when using a switch to change the feedback resistor?

Try adding a 1000uF 16v cap in series with the gain resistors. There is no DC path made back to the feedback input which is the base of the input transistor so as long as this cap is big enough to keep the roll off point in the less then 5Hz point all should work fine and no clicks.

Quote
Do you use a ?Make Before Break? switch?

Either type of switch will make clicks as the DC level changes with each gain step when no cap is fitted. But adding the series cap should fix this as shown in the two circuits below.

(http://www.jlmaudio.com/SpectraSonics110Aasmicpre640.gif)

The two ways to switch gain with a three position switch or centre off toggle will work with either card type.

(http://www.jlmaudio.com/SpectraSonics110asmicpre640.gif)

If someone can try the cap on a existing build and see if the clicks stop and all works fine please post on this thread your findings as I have only been able to computer simulate the cap idea at the moment.
Title: Racking Spectra Sonics 101
Post by: cannikin on June 12, 2006, 09:28:45 AM
Joe you Rock thanks SO MUCH :thumb:  :thumb:  :thumb:  :thumb:  :thumb:
Title: Racking Spectra Sonics 101
Post by: cannikin on June 12, 2006, 11:43:15 AM
edit :grin:
Title: Racking Spectra Sonics 101
Post by: clintrubber on June 12, 2006, 05:48:50 PM
Quote from: "JLM Audio"
Quote
Since from what I read I got the impression that the 600 Ohm input impedance of the 101 & 110,
even when used with a 1:1 TX, give a bit too low inp.imp, correct ?
As in 'it will do just fine, but might have been a bit more'.

I usually like the sound of most mics with 600ohm loads except ribbons.

Thanks for adding that - it's the last push to convince me to make it first as the version for which there's ample evidence around that they're nice mic-pre's. :wink:  
Can always easily convert to the higher input-Z, if ever required.
So 101 or 110 it'll be, thanks,

  Peter
Title: Racking Spectra Sonics 101
Post by: matta on June 12, 2006, 06:20:58 PM
Hey David,

Any luck? Thanks Joe for the words of wisdom. I think I mentioned a while back that the DC was an issue and cap may be the answer, but what cap and what value i had NO idea.

I'm quite happy with the Variable Pad with card fixed to Max gain. but this will be cool as well.

Matt
Title: Racking Spectra Sonics 101
Post by: cannikin on June 12, 2006, 09:49:05 PM
Hey Matta,

Nope haven't tried yet I'm still in the trenches of assembling..
Hopefully will have an answer in the couple days.

(http://homepage.mac.com/cannikin/.Public/spec2.jpg)
Title: Racking Spectra Sonics 101
Post by: guavatone on June 13, 2006, 01:28:12 AM
Love those big juicey knobs!

I thought I saw someone asking about components for 101s.


The top is from a NOS comp/lim.  Bottom is a card from Dotty.
The Tranies are the same but newer.  The only big difference is probablt the  Micas on the newer one.  Maybe this is why I don't like the sound.
(http://www.guavatone.com/free/ss1.jpg)
Title: Racking Spectra Sonics 101
Post by: guavatone on June 13, 2006, 04:51:32 AM
dbl post
Title: Racking Spectra Sonics 101
Post by: cannikin on June 13, 2006, 08:20:43 AM
Hey Charlie

what are the newer replacements for 2n3566 and 2n3645  that are on the NOS com/lim card??
Title: Racking Spectra Sonics 101
Post by: cannikin on June 13, 2006, 05:23:22 PM
edit :grin:
Title: Racking Spectra Sonics 101
Post by: guavatone on June 13, 2006, 10:48:08 PM
Ok from top to bottom looking at the component side with the edge contacts  facing up.  I am listing exaclty what is on the transistors.

FPN
3566
EBC

FPN
3566
EBC

N552   (the N i think is National logo with arrows on the stems of N)
PN
3645

N552   (the N i think is National logo with arrows on the stems of N)
PN
3645

MPS
3566

My mica caps say "050D03" -is that 5 pf?
Title: Racking Spectra Sonics 101
Post by: cannikin on June 18, 2006, 12:03:45 PM
Quote from: "JLM Audio"
(http://www.jlmaudio.com/SpectraSonics110asmicpre640.gif)

If someone can try the cap on a existing build and see if the clicks stop and all works fine please post on this thread your findings as I have only been able to computer simulate the cap idea at the moment.


Hey Joe -

This Build with the 1000uf cap does not solve the clicking issue.

Would putting a cap on both ends of the switch be a potential solution?
Title: Racking Spectra Sonics 101
Post by: JLM Audio on June 19, 2006, 06:25:54 AM
Hi David
OK the DC thumps should be gone but if a non shorting switch is used the pre will jump to huge gain in between gain steps. So if there is no clicks with no input signal but loud clicks when switching with a input signal a shorting type switch will be needed or use the toggle setup on the 110A circuit as it limits the gain jump up to 10dB. Hope that makes sense.

Let me know what you find.
Title: Racking Spectra Sonics 101
Post by: cannikin on June 19, 2006, 09:48:00 PM
:grin:  :grin:
Title: Racking Spectra Sonics 101
Post by: clintrubber on June 20, 2006, 06:21:32 AM
Quote from: "cannikin"
Hey Guys

Scanned and put in Adobe Illustrator -- not perfect but pretty good (not a illustrator master) :cool:  :cool:  

Thanks ! Always handy - I've put 2 channles worth of components on Veroboard already, but no soldering yet. While the various pics around showed the traces already, your diagram will be the most convenient when wiring it.

Regards,

  Peter
Title: Racking Spectra Sonics 101
Post by: guavatone on June 20, 2006, 06:20:23 PM
I finally have  hs-67j XFMRs now.  What is best?  on output?  Will the phantom on input mess up the card without input XFMR?
Title: Racking Spectra Sonics 101
Post by: guavatone on June 21, 2006, 02:37:53 AM
A little update on the NOS cards.  I did AB to the old ones I got from Doty and so far the NOS is much "better" with more bass.  I may move this to another thread and post sound files.  I just recapped the 220uF caps on the old one to see if it comes close.
Title: Racking Spectra Sonics 101
Post by: cannikin on July 08, 2006, 11:38:03 PM
GuavaT

I used the A-67J on input....

My recommendation is:  Wire it 150:600 (1:2) it sounds so much better (to me).

I had 2 pair of cards One set I wired 1:1 the second I wired 1:2.

IMO The 1:2 was much fuller in sound.

Secondly I recapped the "big" caps with Sprague Atoms
Mouser Part #:

75-TVA1223 200uf 35V
75-TVA1312E 250uf 35V

The bass really came alive!  Really like the sound of these they're my favorite pre right now
Title: Racking Spectra Sonics 101
Post by: cannikin on July 08, 2006, 11:44:04 PM
Guys can you recommend a good "make before you break switch" for the feedback resistor.. the popping is the one thing that is driving me crazy!

Next "test" wiring up a newly etched board using BC560 BC550 Transistors
DO you guys know the ECB configuration for 2n3566 and 2n3645?
Title: Racking Spectra Sonics 101
Post by: clintrubber on July 09, 2006, 08:21:21 AM
Quote from: "cannikin"
Next "test" wiring up a newly etched board using BC560 BC550 Transistors
DO you guys know the ECB configuration for 2n3566 and 2n3645?

I thought they're all EBC, just like BC5X0. But with the PCBs already in hand it's easy, just follow the traces to the other components & see what each hole needs to be, E, B or C.

Keep us posted  :thumb:

Regards,

  Peter
Title: Racking Spectra Sonics 101
Post by: cannikin on August 23, 2006, 08:08:47 PM
Hey Guys...

Just curious.. I have some "make before you break" rotary switches.  but they are 12 position.

I was wondering if you could add more values to the feedback resistor
Between 5.6K and 42.2K to make more gain control...

thanks
Title: Racking Spectra Sonics 101
Post by: matta on August 23, 2006, 08:10:42 PM
It makes sense David, if you got it, do it! The issue I still have with the switches is that I got  loud pop when switching, I tried MBB and BBM and both had the same results? Are you having any better luck?

Cheers

Matt
Title: Racking Spectra Sonics 101
Post by: cannikin on August 23, 2006, 09:05:14 PM
I haven't tried a make before you break switch yet ... so I'll give that a try
and report back
Title: Racking Spectra Sonics 101
Post by: frob on January 19, 2007, 05:18:52 AM
just a sugestion, but this should be in the meta.
Title: Racking Spectra Sonics 101
Post by: frob on January 24, 2007, 12:10:14 AM
has anyone tryed the make before break switch with a cap yet. and does it solve the problem of the pops?
Title: Racking Spectra Sonics 101
Post by: cannikin on January 24, 2007, 12:34:55 PM
Joe mentioned a cap before the switch - page 6 of the thread.

I got a make before you break switch in addition to the cap fixed the "pop" issue for me.
Title: Racking Spectra Sonics 101
Post by: frob on January 25, 2007, 04:12:17 AM
good it does work then. also did you just use the four possition switch or did you figure what the values would be for more stages? i just got two and so i am kind of excited.
Title: Racking Spectra Sonics 101
Post by: hejsan on February 07, 2007, 01:49:00 PM
Hi, I'm starting racking up of a pair of channels.

On the 101 cards, are there only 2 caps that need to be replaced, or are some of the small capacitors also electrolyte?

What capacitors have you guys used?

Thanks,
hejsan
Title: Racking Spectra Sonics 101
Post by: 3nity on April 04, 2008, 10:28:43 AM
i'm trying to gather all the info i need to finally rack mines...but i have a question if i usae  a rotary switch for steped gain is there anyway i should be able to install an output trimmer?? or should i use a 50K rev Log instead?
thanks.
Title: Racking Spectra Sonics 101
Post by: Animatic on July 18, 2008, 01:00:37 AM
Used to have a studio rack FILLED with these things.
3 dozen or more SS 101's, and sad to say, without consulting me,
the whole rack went to a landfill decades ago.  
I was sad then and sadder now...

It was out of a rebuilt Flickenger console.
Or maybe the SS were the rebuild new parts.

As to the feedback gain question a simple 25k linear pot
would easily replace the resister choices I think.
Personally I would use a 50K.
put it in and run it with a scope
and mark your DB points on a scale.
Nothing really says it needs to be fixed.
Title: Racking Spectra Sonics 101
Post by: 3nity on August 23, 2008, 12:29:59 PM
How old are those boards? Do you think they could something wrong? with them given the age on them?

Like resistors or non electro caps ( i already replaced the electros)

Thanks by the way.
Title: Racking Spectra Sonics 101
Post by: Animatic on August 23, 2008, 01:42:17 PM
Likely pre 1970...
The're cool,
but the same thing is smaller than your fingernail these days.
And likely cleaner.  But they are still interesting
and should have a defined sound.
Only listening will decide if this is a good sound for you.
IMHO.

I find it interesting that so many are looking to the tech of the past,
to create the sounds for tomorrow. I still love tubes.
Title: Racking Spectra Sonics 101
Post by: 3nity on August 23, 2008, 08:24:02 PM
The reason why i asked that...its cuz theres a 10R just after the 24 volts pad...burning every time i powered the cards!

What can be wrong?
Title: Racking Spectra Sonics 101
Post by: raysolinski on August 23, 2008, 11:46:39 PM
Bad transistor? these guys are pretty simple...do you have the schematic? I know I have one around here somewhere.....

Ray
Title: Racking Spectra Sonics 101
Post by: Animatic on August 24, 2008, 12:10:57 AM
I'd say try a much lower voltage like 5v and see what's happening around
the circuit WITHOUT smoking it. Gradually bring it up and check voltages/current etc.
Title: Racking Spectra Sonics 101
Post by: 3nity on August 24, 2008, 09:20:57 AM
I'm gonna try that...(lower voltage)...
I'm pretty sure its a bad transistor but hey where can i find this oldies?

I'm thinking of lift some parts, where power  flow trough and see if the 10R still burns untill i identify the bad part.

Thanks guys.
Title: Racking Spectra Sonics 101
Post by: Animatic on August 24, 2008, 09:42:51 AM
Post a parts list.
I am sure there are close approximations still available.

If I still have a schematic for these,
it is 10 boxes down, in a storage box 12,000 miles away.

But they shouldn't be hard to draw out.
Might be a useful thing to do anyway.
Title: Racking Spectra Sonics 101
Post by: 3nity on August 24, 2008, 04:48:47 PM
heres the schematic:
http://www.technicalaudio.com/a2z/S/SpectraSonics/SpectraSonics_101sch1.pdf
Title: Racking Spectra Sonics 101
Post by: 3nity on August 24, 2008, 07:30:20 PM
before going on with the trouble shooting i wanna make sure that wiring is right...

heres a pic of how i did it...
(http://www.twin-x.com/groupdiy/albums/userpics/ss_101_cards.jpg)

I;m sorry for not getting it guys...
Title: Racking Spectra Sonics 101
Post by: Animatic on August 24, 2008, 11:19:15 PM
Man! is THAT nostalgic.

Talon has the 2N4248, 2N3566,  transistors in stock

http://www.talonix.com/shop/item.aspx?itemid=3292

TheCS1711 is discontinued but here's the data sheet

http://www.datasheetarchive.com/pdf-datasheets/DataBooks/52-68.html


One stupid question.
Were you using the feedback gain pot turned low?

At this age caps are the 1st choice for things gone bad.
Resisters might change value a bit, but not quite die off yet.
Title: Racking Spectra Sonics 101
Post by: clintrubber on August 25, 2008, 08:49:25 AM
IIRC the circuit in the patent featured a few Ge-transistor types, yet most/all implementations here use all-Si. Anybody knows more ? Maybe most of the real-world boards had Si perhaps ?
Hah, maybe they had already switched to all-Si by the time the patent was granted (1968) :wink:

From the patent I get the impression that at the time of writing (1965) the choice for Ge or Si was partly influenced by the cost of the one over the other, who knows that might have been the main reason... ?

http://www.pat2pdf.org/patents/pat3376515.pdf
Title: Racking Spectra Sonics 101
Post by: 3nity on August 25, 2008, 02:40:43 PM
I used a 10K resistor as a fixed gain.
Title: Racking Spectra Sonics 101
Post by: 3nity on August 26, 2008, 08:01:27 PM
bump?
Title: Racking Spectra Sonics 101
Post by: Baltimore on August 26, 2008, 09:03:18 PM
assuming you have your 10k resistor between the pins labeled "signal in" and "signal out" then i believe it is wired correctly.
Title: Racking Spectra Sonics 101
Post by: 3nity on August 26, 2008, 09:24:35 PM
Thanks Baltimore.

now if you look at the schematic....Between the 2N4248 and 2N5366 theres a capacitor...4.7uf/35V is that polarized or not...if yes negative goes to ground??

I lifted fromt the pcb and the card dont smoke anymore!!!! :green:
Title: Racking Spectra Sonics 101
Post by: 3nity on August 27, 2008, 04:41:18 PM
anyone?
Title: Racking Spectra Sonics 101
Post by: Animatic on August 28, 2008, 01:38:52 AM
Well it SEEMS to be creating some relative or maybe virtual ground vs 24v power.
In many schematics polarized caps have a curve and a straight line.
and non-polarize is just two straight lines. As show here.
But I am not familiar with the standard of this era.

It is also not on the 1965 drawing. So maybe you can try it with it out.
Of course looking at what was on the board to begin with is a good hint.
Title: Racking Spectra Sonics 101
Post by: 3nity on August 28, 2008, 04:53:40 PM
I did tried a 25uf/25V and its working fine but it has some warmth...altough almost hard to tell but it was there...gonna try a bigger voltage one....
Title: Racking Spectra Sonics 101
Post by: 3nity on August 31, 2008, 10:45:22 PM
I got one of the cards working on theory....but i dont have sound with a mic plugged.... altough for a moment i forgot to unplugged the preamp from my headphones amp and i heard the 1k  wave coming from my Generator...hum??

One step at a time! :thumb:
Title: Racking Spectra Sonics 101
Post by: 3nity on September 01, 2008, 01:06:04 PM
cool i got it! i got 1 channel working!!!
Everything was fine but i forgot to wire XLR pin 1 to OEP.

Cool!!!


I think i;ll have to remove the foroidal from the rack cuz i have some RF.

 :green:  :thumb:
Title: Racking Spectra Sonics 101
Post by: Animatic on September 01, 2008, 09:33:28 PM
mereveaux c'est bien!

Toroidals do seem to make RF,
maybe a Cinimag in Mu metal can etc?
Title: Re: Racking Spectra Sonics 101
Post by: hairymoses06 on February 02, 2009, 01:05:12 PM
I've noticed it's been awhile since anyone has posted on this site. I've got a pair of 110 cards that I want to rack up. I'm going to buy JLM audio power supply and go between, but I have no idea on what transformers to buy. Does anyone have suggestions for transformers that they have used? I of course need the 600Ohm 1:1 or 1:2. THANKS!
Title: Re: Racking Spectra Sonics 101
Post by: 3nity on February 02, 2009, 11:07:11 PM
I'm not sure but they used triad on input....some of them used Jensen too...
Right now i'm using Jensen 600:600.
Title: Re: Racking Spectra Sonics 101
Post by: electrochronic on February 03, 2009, 02:43:24 AM
Anyone use a T66 trasnformer ? there in a black and look a lot like a Triad HS66 , but the windings seem differentns
Title: Re: Racking Spectra Sonics 101
Post by: rattleyour on February 03, 2009, 03:16:40 AM
I have four 110s racked up, we used Cinemags on input-- CMMI-2C.

For output I used some old iron that folks here at the lab helped identify as (probably) stancor.
Title: Re: Racking Spectra Sonics 101
Post by: hairymoses06 on February 03, 2009, 02:36:06 PM
Thanks for the help on the Xfrs. I was just given 2 Reichenbach RE 11SSP-6M. I think they're similar to Jensen, but I'll have to put them on a scope and see what they read. I think they're gonna be 600:600. I found a set of Triad A-67J ...but they're in Vietnam...not sure how I feel about that transaction. I'll be sure to post some picks when I get them racked.
Doug J.
Title: Re: Racking Spectra Sonics 101
Post by: goldenGeek on February 09, 2009, 05:38:00 AM
I just finished racking a SS101 and it seems to be working fine finally. But I stubled upon something that probably is like it should be, but I though I`d ask anyway. Is it correct to connect pin E and F (signal input - and signal output - ) and then connect it to ground? It was the only way I could get sound out of it. The weird part is that if I grounded this at my star gound to the back of the chassis I got a ground hum. If I grounded this anywhere else closer to the front panel the hum was gone. Why did this happen do yiou think?
Title: Re: Racking Spectra Sonics 101
Post by: 3nity on February 09, 2009, 09:44:20 AM
you went unbalanced out or transformer balanced?
E, F and C are 0V, ground reference.
i used F as reference for input transformer, E for 24V reference and C for output transformer reference.

Matta gently posted a ground scheme for this board....they go from certain points straight to star ground.....
Title: Re: Racking Spectra Sonics 101
Post by: bdubya on March 20, 2009, 08:12:20 PM
Hey now.  Just wanted to extend a big thank you to all ya'll on this thread.  Just finished racking up a 110 card in a case from some old data network equipment, with a jlm power supply run off a wall wart.  Sounds fantastic, quiet, and BIG.  Would never have even known a thing about any of this stuff without this forum. Props.

bw
Title: Re: Racking Spectra Sonics 101
Post by: 3nity on October 13, 2009, 09:04:51 AM
Just to hear what i sounds like i wired the input unbalanced and i'm amazed at how good it sounds..
It sounds louder first thing and i think its not dark like with any 600:600 input.
To my ears it sounds more open and coloured...first real tests....
Title: Re: Racking Spectra Sonics 101
Post by: bdubya on January 07, 2010, 03:27:47 AM
So, instead of the dual 1k log pad in front of the input transformer, could one use the 600-ohm attenuator that Hairball sells, or am I misunderstanding the affect that the attenuator would have on the input impedance?  I know its more expensive than the the dual-pot, but I like the curve of that attenuator in both the 1176 and the VP26.  It covers the ground evenly, so to speak. 





ben
Title: Re: Racking Spectra Sonics 101
Post by: bongolijus on April 04, 2010, 09:57:23 AM
Can someone confirm what ratio transformers needed for the 110A model? Are they 150/600:2k5 ohm on input and 600:600 ohm on output?

Thanks.
Title: Re: Racking Spectra Sonics 101
Post by: techardent on June 03, 2010, 11:32:05 AM
If anybody is interested.  I found this in my Spectra Sonics file.  As I understand it a lot of the components were hand picked for amplifier stability.  I am unsure who filled in the values.  I removed the link between R3 and R4 to make it accurate to the the actual card.

(http://ardentstudios.com/tech/spectrasonics/Spectra-Sonics-101-card.jpg)
Spectra Sonics 101 / 100 schematic
Title: Re: Racking Spectra Sonics 101
Post by: rocksure on March 12, 2011, 05:11:58 AM
Quote from: JLM Audio
(http://www.jlmaudio.com/SpectraSonics110asmicpre640.gif)


I am currently racking a pair of these using Triad A67j input transformers and Jensen JE-123A output transformers. This may seem like a silly question, but looking at the pinout in the picture, if I send the 0v  from the input transformer to pin E, and the 0v from the card ( pin F) to the power supply common, where is the best place for me to connect the 0v from the Jensen output transformer?
Title: Re: Racking Spectra Sonics 101
Post by: rocksure on March 14, 2011, 01:59:01 AM

I am currently racking a pair of these using Triad A67j input transformers and Jensen JE-123A output transformers. This may seem like a silly question, but looking at the pinout in the picture, if I send the 0v  from the input transformer to pin E, and the 0v from the card ( pin F) to the power supply common, where is the best place for me to connect the 0v from the Jensen output transformer?
Bump....Anyone out there?


Quote from: JLM Audio
(http://www.jlmaudio.com/SpectraSonics110asmicpre640.gif)


I am currently racking a pair of these using Triad A67j input transformers and Jensen JE-123A output transformers. This may seem like a silly question, but looking at the pinout in the picture, if I send the 0v  from the input transformer to pin E, and the 0v from the card ( pin F) to the power supply common, where is the best place for me to connect the 0v from the Jensen output transformer?

Title: Re: Racking Spectra Sonics 101
Post by: AJMAC on March 25, 2011, 04:36:48 PM
So I'm racking up a pair of 101 cards using Joe's diagram (Thanks Joe!)  I am using A67J input wired 600:600 and HS66 on output.  I have a couple questions however..I have the output of the card wired to the primaries of the transformer and the secondaries connected to XLR out.  It works, but after re-reading the thread for the 10th time it seems I've got it backwards.  Since the transformer is 1:1 does it make a difference?  Should I wire secondaries to the card and primaries to the XLR?  Also, PRR mentions using a resistor in series to keep the card from damping out the iron sound.  Could someone elaborate on this in noob terms?  Also, what value resistor would be suitable?  Thanks!!
Title: Re: Racking Spectra Sonics 101
Post by: drew baker on June 17, 2011, 12:00:36 AM
Hello,
I first want to say what an amazing board this is. It is remarkable how polite and intelligent everyone is here. Thank you all so much for the information on the spectrosonics 101 cards,I am trying to breadboard one as I type. Cannikin, the 103 board you have is a summing card.
I think it might be the unsung hero of the Spectrosonic console. If I understand it is 0 ohm input summing amp. I think it predates the SSL low impeadence summing amp by 20 years. Is thee any way you could post color photos of the front and back of the card,I would love to try
to bread board one. Once again thank you all for your information, I look forward to participating in this great forum.
Drew Baker
Title: Re: Racking Spectra Sonics 101
Post by: rocksure on July 28, 2011, 03:27:37 AM
I finally got my 2 channels of Spectra Sonics 110 racked and up and running. They sound really good. Nice and warm and fat. Quite a bit of work and time consuming to do, but well worth the effort and cost of racking them up. No issues with noise or hum, as I was pretty careful to ground everything as well as using metal shields round things like power supply and transformers (just to make sure).
I am not too clued up on electronics really, and so I had a few minor problems working it all out, but with a bit of help from a friend who is an electrical technician we nutted the issues out. I have Triad A67-J transformers on inputs and Jensen JE-123-A's on outputs. I used a JLM AC/DC to power them, and JLM go-between and variable pad kits for attenuation, phase and 48V. On the picture I have posted here, I have the labels for these underneath the switches, they should have been on top. I have subsequently changed the labels. I have no output gain control: output is fixed with the use of 42k resistors. I have around 40db of input gain control via the JLM input pots and attenuation switches.
I am very happy to have these.  :)
Title: Re: Racking Spectra Sonics 101
Post by: bassinyourface on January 30, 2012, 03:44:54 PM
Hi all,

Just a quick note to say that this topic is fantastic,lots of useful info !

Some pretty neat racking here too : knowledge and ingeniosity go a long way.

I just wanted to add an insert to the circuit ( for connecting an eq or compressor)

What do you think would be the optimal spot ?
Title: Re: Racking Spectra Sonics 101
Post by: superjimmer on March 18, 2012, 04:03:36 PM
Hi Guys I am looking to trade a pair of SS 110a/502 modules in a really cool rack with PSU and VU meters for some modules for my console.

Here is a movie of the unit at work:

http://dl.dropbox.com/u/5629729/IMG_3001.MOV

Now for the deal! I am looking to acquire more Spectra Sonics modules, so if you have any spectra sonics parts or modules that you never racked up let's trade. I am trying to put a console together and need more 502/110a modules and possibly other parts. I am looking to trade this unit, loaded with two modules, for four of your raw modules etc.

So if you never racked yours up here is your chance to plug and play and help a console get rebuilt. This rack and vintage API meters with FiveFish PSU, custom rack etc plus mod/rewiring labor from a tech has easily cost me $1500.00 not counting modules. But it sounds amazing!

In addition to this amazing rack I have other console parts, bus modules, anodized gold meter panel, some old meters and more. Just trying to get my console running. And lemme tell you I am not one of those guys who famously lucked into one. I have paid through the nose for every part. Just a love affair with this sound.

pm for more info. It currently runs at 17.5 volts, but can go to 24 volts if you want to mod it. Also the attenuation pots you see are very high quality but not wired up as I liked the simple -10 -20 -30db switches. I also have it wired for line in but the XLR's are on pigtails - you can run them out a hole or install the TRS jacks I have included in this deal (pictured).

When I find out how to post pics I will. I have 100% positive trading on ebay since 1998 and Gearslutz since 2003 and can provide references and contact info if you PM me!
Title: Re: Racking Spectra Sonics 101
Post by: superjimmer on March 18, 2012, 04:07:50 PM

Here is a pic of my Spectra Sonics 110a/502 racked pair with original SS API VU meters.
Title: Re: Racking Spectra Sonics 101
Post by: rocksure on September 14, 2012, 08:33:47 AM

Here is a pic of my Spectra Sonics 110a/502 racked pair with original SS API VU meters.

It looks really nice. I'm still loving the sound of my racked pair. They really excell on electric guitar cabinet micing among othe rthings.
Title: Re: Racking Spectra Sonics 101
Post by: toddro on March 18, 2013, 06:48:46 PM
I know this is one year old, but I wanting to rack up a 110/502eq set and my eq's came from an old broadcast console with a custom faceplate.  Can anyone post a straight-on shot so I can see the toggle switch & gain / freq pot positions?  When I pulled them off the console I was forced to leave the faceplates behind and need to build a new one.  Somehow, the photos of the console I took have disappeared and I have been unable to locate a shot clear enough to see what the positions are.

Superjimmer, nice build!!!  That is what I am shooting for!

Thanks.

Todd
Title: Re: Racking Spectra Sonics 101
Post by: Whoops on May 05, 2013, 02:02:14 PM
So I'm racking up a pair of 101 cards using Joe's diagram (Thanks Joe!)  I am using A67J input wired 600:600 and HS66 on output.  I have a couple questions however..I have the output of the card wired to the primaries of the transformer and the secondaries connected to XLR out.  It works, but after re-reading the thread for the 10th time it seems I've got it backwards.  Since the transformer is 1:1 does it make a difference?  Should I wire secondaries to the card and primaries to the XLR?  Also, PRR mentions using a resistor in series to keep the card from damping out the iron sound.  Could someone elaborate on this in noob terms?  Also, what value resistor would be suitable?  Thanks!!

PRR mentions using a resistor in series to keep the card from damping out the iron sound.  Could someone elaborate on this in noob terms?  Also, what value resistor would be suitable?
Title: Re: Racking Spectra Sonics 101
Post by: duantro on December 28, 2013, 12:43:57 PM
Getting ready to rack a pair of ss101's and really appreciate all of the info here! Cheers
Title: Re: Racking Spectra Sonics 101
Post by: j.frad on June 10, 2014, 09:02:11 AM
Hi everyone, what would happen if I lowered the supply voltage to, say, 16v ?
Wondering if I can make 500 series modules with them...
Title: Re: Racking Spectra Sonics 101
Post by: bxt403 on August 31, 2018, 11:28:38 PM
I've realized that Spectra Sonics modules should definitely be sent to Ogden and Spectra Sonics (now apparently called Spectra 1964) for repair and/or refurbishing.  I sent two 101s that didn't match (age wise) and Spectra replaced one of them (while also refurbishing them).  They did an excellent job repairing my 110s, as well (and converting them to 110As).   

In any case: I've just completed racking a pair of 101s so figured I should share some gain resistor values as an alternative to the (I think) "JLM" method of having 3 gain settings and a variable pot at the input transformer.

You'll need a non-shorting rotary switch as a shorting type causes loud thump sounds (from gain instability).  I  haven't had any issues with gain stability using a non-shorting type rotary switch with my 110 (in that I hear a very faint clicking sound).   I noticed the clicking sound is significantly louder with the 101 (likely since the 101 only needs a +24 VDC supply to work while the 110 requires + & - 24 VDC).  It's not as bad as the loud thumping I'd hear when using a shorting type switch with the 110 but it's still apparent.

Note that I did the algebra on the gain equation found in the original Spectra Sonics manual and made a spreadsheet to do the calculations.  The numbers given are for the EXACT (theoretical) resistor value that'll yield the EXACT gain value number.  Since the gain equation is given in the 101 manual: it should be easy to figure out which gain is yielded from the actual resistor values that are available from electronics suppliers.

The spec sheets for the 101 and 110 both state the gain for each module is adjustable to 40dB to 55dB (which contradicts the manual that gives a resistance for 35dB).  Given the specifications of the 101 (and 110): I'm certain 40dB is the optimal MINIMUM gain setting .   


Gain (dB)     Resistance(kΩ)
    40                     11.111
    41                     12.638   
    42                     14.402
    43                     16.449   
    44                     18.834
    45                     21.629   
    46                     24.926
    47                     28.845   
    48                     33.545
    49                     39.244   
    50                     46.248
    51                     54.994   
    52                     66.143
    53                     80.728   
    54                     100.476
    55                     128.489  (the "actual" value I got was 127kΩ @ 54.96dB)

Also: Jensen (at the time of this post) makes the line input JT-11SSP-6M and the line output JT-11SS-DLCF transformers (where I suspect the SS might actually stand for Spectra Sonics).  I'm guessing that the sound from these transformers will be less coloured than using vintage Triad A-67J  + HS-66 transformers (albeit only the DLCF mentions 50% Nickel content while the 6M sheet doesn't list anything about its Nickel content).  Pricewise: a used Triad A-67J and the Jensen JT-11SS-DLCF are probably the best combination (given how expensive the HS-66 tends to be and JT-11SSP-6M is). 

 :)