Is Summit TLA100 optical, or what?

[strangeandbouncy]

Hi,


  I haven't had the pleasure of using one for quite a while. I was just wondering id any of you cats know what kinda compressor it is? it is optical, surely(?)


    Anyone got a schemo by any chance? I am just interested to know what's under the hood, not to clone!



    Kindest regards,


      ANdyP

 

[mik]

It's a varyMu type, I do not have any schema.

Mik.

 

[strangeandbouncy]

Mik,


    Thank you for reply, but I would be extrememly surprised if it were vari-mu, since the Compression cell has no HT or LT going to it . . . . Any tube would be far to big to squeeze into the encapsulated box iirc


    Kindest regaRDS,


    ANdyP

 

[pucho812]

the manual says

The TLA-100A features a vacuum tube amplifier driving an electronically
balanced 990 output stage. All the signal amplification in the audio path
takes place in the tube circuit. The 990 amplifiers provide a low output
impedance for driving cables and 600 Ω loads. The 990 is a high
performance op amp made of discrete parts, and then potted for thermal
stability.
The input is electronically balanced, and directly feeds the unique
compression cell. The SIDE CHAIN allows for stereo coupling, or the
insertion of an equalizer. Due to the combination of tube and solid state
circuitry long term drift of the compression circuit is minimal and tracking
of two TLA-100As stereo linked is within .3dB.

compression cell sounds a lot like an opto cell and not a vca


great units although I was unaware of the 990 circuit inside as I never opened one up. I wonder how it would sound with a 2520 instead?

 

[strangeandbouncy]

Hi,


    I found a schematic, but giving no details of the compression cell, other than hook-up. There are no + or -15v, or 180v connected, so I am erring on the optical side at the mo, unless someone else can chip in?


  Does anyone know what the compression cell in a TLA50 is? is it the same do you think? I have one here, and might be persuaded to 'ave a CJ, since I don't use it much. I would use a TLA100 loads and loads . . . .


    Kindest regards,


      ANdyP

 

[strangeandbouncy]

Oops!


  I see that there is +15v, via a 20k trimpot.


  AndyP

 

[pucho812]

my vote is optical as they compare it to an la2a. Build one using a t4b ;D

 

[amorris]

http://optoelectronics.perkinelmer.com/content/applicationnotes/app_analogopticalisolatorsvactrols.pdf

 

[MartyMart]

Optical, quite LA2a "sounding" I have the "50" and it's pretty damm good for a half rack
sized jobbie !

MM.

 

[mushy]

I've got a DCL-200 but I love me some TLA100. I always thought it was optical but I also always wondered how they got the variable attack and release in there.

I'd say call them. They're a cool bunch of dudes.

Wouldn't it be funny if it was a potted VCA?

 

[gyraf]

There must be some active stuff inside that gain cell: note the very high input impedance (0.1uF input capacitor) - and the low output impedance (drives a 10K potentiometer from it's output)

Sent some additional schematics and alignment procedures to the group Gmail account.

Jakob E.

 

[strangeandbouncy]

HI,



      Thanks, Jakob! Most interesting! Lets hope someone can shed some light on the "compression Cell" . . . .


      Kindest regards,


 
            ANdyP

 

[Tubemooley]

I have a DCL-200. I have 3 TLA-50's. I don't have a TLA-100. The compression cell in the DCL and probably also in the TLA is not optical. I am pretty certain it is a PWM device. David Hill designed it when he was still at Summit. They don't give out much (or any) info on that device. The guys at Summit are very cool. I know Paul Grove, head of customer service. Mike Papp started the company (I think) but he has retired. His son Eric now runs the business. They used to be in northern Cali, just south of San Fran. But they have since moved to Arizona. The compression cell does not wear or degrade over time like most opto-devices. And yes, most of the full-sized Summit boxes (not the half-rack boxes) have Summit SA-990 discrete opamps in there. The SA-990 is pretty much exactly a Deane Jensen 990 but the original version and not the 990c later version with that additional filter in there. A 2520 would probably work OK in the Summit boxes but I wouldn't put money on that. The Summit circuits (just like any other quality box) are highly tuned and optimized for those amplifiers. A 2520 is different from a 990. I know what the SA-990's are because I asked Paul Grove about 6 months ago. I also have one of the earlier TPA-200 dual tube preamps. It's the A version and not the B version. It's sick. Summit gets the lovely tube harmonics in their circuit. And then their 990-based output circuits are just the sickest, cleanest, loudest things going. I calibrated my TPA-200 about two years ago and it drove to +34dBu before clipping. Friggin' amazing. I own 17 boxes from Summit and yes, I have problems. Big problems. DW.

 

[strangeandbouncy]

HI


  here is poor piccy of the tla50 compression cell


  looks like an opamp and a transistor array(?) to me. I wonder if it is the same as TLA100?



  Kindest regards,



      ANdyP

 

[amorris]

VACTROL optical

 

[mushy]

I have a DCL-200. I have 3 TLA-50's. I don't have a TLA-100. The compression cell in the DCL and probably also in the TLA is not optical. I am pretty certain it is a PWM device.

Eric has told me that the DCL-200 and TLA-100 work on completely different principals. He also said that the compression cell in the TLA-50 is similar in design, but of course not the same.

 

[strangeandbouncy]

Oh well,



  so  we're no further down the line then! To my ears, the TLA50 is much "squashier" than the TLA100, which is SO transparent. It is a while since I had the pleasure of the TLA100, and I have never made a direct comparison. I am really tempted to whack in a 2520 instead of the tube/ss output, and see how it sounds! I like the action of the TLA50, but it is a tad rough 'n ready as is.


  Kindest regards,



      ANdyP

 

[Johan]

judging from the blurry pic..OTA built up by transistor array's?..
j

 

[strangeandbouncy]

Please forgive my ignorance, but what is an OTA?




    ANdyP

 

[Johan]

Please forgive my ignorance, but what is an OTA?

    ANdyP

operational transconductance amplifier  http://en.wikipedia.org/wiki/Operational_transconductance_amplifier
it's just a wild guess based on the blurry pic, but would fit Jacob's "Hi-z in, low-Z out active device"
..OTA's have been used as compressors before ( the CA3080 in MXR Dynacomp and ROSS compressor comes to mind) and sidechain responce can be tuned to give the feel of optical if thats what they wanted  ..but I really dont know, just something that came to mind based on a blurry pic and I'm sure someone else will come up with a much better idea/explanation/answer for what that thing is.. ;D
j