TS-990 // Twin Servo Mic Preamp for 500 series

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elskardio

Well-known member
Joined
Sep 29, 2010
Messages
560
Location
Montreal - Canada
Hi Guys,

I just wanted to share my latest project. It's my take on the Jensen Twin Servo for the 500 series format.
I'm using Cinemag transformers at the Input & Output.
The discrete opamps are my version of the 990.
So far this is my favourite mic preamp. A lot of clean gain and well balanced over the frequency range.

Cheers
Gabriel


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I finally assembled the latest revision with the 10dB output Trim. Huge Jensen on the output. Lots of clean gain 8)

TS990-Trim-Front.jpeg

TS990-Trim-Side.jpeg

TS990-Trim-Back.jpeg


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Update November 4:

Here's the latest revision with bias adjustment for the discrete opamps and pcb footprint for Jensen transformers.

TS-990_Front_800x800.jpg

TS-990_Jensen_800x800.jpg

TS-990_Cinemag_800x800.jpg
 
Last edited:
Wordsushi said:
Yeah, that looks pretty amazing. Any thoughts on kits/pricing as of yet? I'm super intrigued.

I'm not planning to sell kits at the moment... But if there's enough interest I could probably do a small batch  ;)
 
Looks great.
At one point i did had a couple of prototypes done but never made it past there... I love their 3d type of sound.
Good luck
 
3nity said:
Looks great.
At one point i did had a couple of prototypes done but never made it past there... I love their 3d type of sound.
Good luck

Thanks 3nity
The grounding scheme  is a bit tricky with this one... I made 3 prototypes before everything was 100% stable, even at extreme gain settings.
I just ordered the final PCB revision. I added Bias adjustments for the discrete opamps to help the servo work faster. I also added footprint for Jensen transformers.
I'll post pictures when it's assembled in 1-2 weeks.
Cheers
 
I might do a small batch of kits by the end of the year...

I have the latest revision in intensive test at 2 different studios. So far everyone's loving them.  8)

I'm also testing different flavour of discrete opamps

DOAs.jpg
 
This is a beautiful build. I’d love to build a pair. Even if you don’t do a “kit”, I’d be interested in the PCBs
 
I'm still very interested in a kit.

Have you tried a version of the OA10 op amp? I just put a pair of Gary Bennett's new OA10's in a Hairball Lola and they really sound great. Adds a wee bit of bite that the Hardy 990s don't have. So, as such I have a pair of Hardy 990c's sitting around just waiting for a preamp to be put into...
 
Hi guys,

I updated the first post pictures. This is the latest revision with bias adjustments for the discrete opamps and pcb footprint for Jensen transformers.

I could probably make a few partial kits available before Christmas.

If you're interested, please post the following details:

- Your username
- How many kits?
- Planning to use the CA-990? or another DOA?
- Would you like to have transformers included in the kit?

Cheers
 
elskardio said:
Hi guys,

I updated the first post pictures. This is the latest revision with bias adjustments for the discrete opamps and pcb footprint for Jensen transformers.

I could probably make a few partial kits available before Christmas.

If you're interested, please post the following details:

- Your username
- How many kits?
- Planning to use the CA-990? or another DOA?
- Would you like to have transformers included in the kit?

Cheers

Ricardus
I would be interested in 2 kits after Xmas. Money will be too tight before Xmas.
I would probably use a different Op-Amp, but would want transformers.
 
elskardio said:
Hi guys,

I updated the first post pictures. This is the latest revision with bias adjustments for the discrete opamps and pcb footprint for Jensen transformers.

I could probably make a few partial kits available before Christmas.

If you're interested, please post the following details:

- Your username
- How many kits?
- Planning to use the CA-990? or another DOA?
- Would you like to have transformers included in the kit?

Cheers
Fuzz Face
2 kits
CA-990
Transformers yes
 
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