60 Sowter trafos in stock, need project

[pesloth]

Hi there!

I have a lot of the attached Sowter transformers.

A lot of 1:1 input and output trannies
Under 10 pc. 1:6 Mic inputs

I would really like to start building 500-series stuff. The better documented the projects are the better for me.

I am looking for DIY Neve/API/etc. sounding preamps, 1176 etc. sounding compressors, API/Neve/etc. sounding equalizers.

No tube designs.

What designs can you recommend me?

best,
Peter

 

[xazrules]

Would you like to sell a couple of mic input trafo?
With 1:1 input trafo you can build a neve preamp but you have not a suitable output trafo because it needs a gapped core to withstand dc current in the primary.
With 1:6 api pre and 1:1 output is cool.
In solid state eq and comps you can use almost everything, just experiment.

cheers

 

[Ricardus]

Sounds like your Sowter inventory is better than Sowter's right now.

 

[pesloth]

Sounds like your Sowter inventory is better than Sowter's right now.

Haha

 

[pesloth]

Would you like to sell a couple of mic input trafo?
With 1:1 input trafo you can build a neve preamp but you have not a suitable output trafo because it needs a gapped core to withstand dc current in the primary.
With 1:6 api pre and 1:1 output is cool.
In solid state eq and comps you can use almost everything, just experiment.

cheers

Thanks! No Neve preamps i see.

Do you know any well documented 500 series preamp builds with 1:1 transformers on in and output?

I would really like to build a whole lot

Best,
Peter

 

[pesloth]

Would you like to sell a couple of mic input trafo?

As mentioned i would like to build preamps/eqs/compressors from the transformers. If i cant find any suitable builds the transformers vill be used as balancing amps before ad-converters to sweeten up the sound of my pro tools rig.

Best,
Peter

 

[oran.outan]

I don't know any 500 series fitting this transformer specifically... but maybe that exist !?
and the 4563 will not fit into 500 series size with that "screw legs".
But you could go for 19" rack and there you will have more possibilities...
Like the ML12/Access312 which is API type preAmp and well documented, probably fews EQ and Comp...

Also, maybe try to find build related to the Transformer... like write the transformer name and see what pop up...

best
F

 

[L´Andratté]

Take this with a grain of salt as I am in no way a pro at this:

1:1 Mic input trafos (those, that are not mic splitters with dual secondaries) are suitable for preamps that are noise optimized without transformer already, so they don´t need an impedance transformation, that means they are only useful for things like RFI protection, galvanic isolation, etc. while their negative sides need to be taken into account too...(possibly distortion, reduced BW)
If I am not mistaken Sowter made e.g. 1:1(200R:200R) for some soundcraft desks like the 200B, B100 etc. Garden variety preamps but I like them pretty well...even without xformers

 

[xazrules]

I’m no 500 series expert, but 60s sowter has different mounting scheme than modern ones. With 19” rack you can mount them off board and open up a lot of possibilities.

 

[xazrules]

Maybe with 1:6 and 1:1 you can find some helios 500 series mic pre, try the search function, they are pretty popular

 

[TwentyTrees]

Maybe with 1:6 and 1:1 you can find some helios 500 series mic pre, try the search function, they are pretty popular

Helios preamp (2128 amp) is optimised for a 1:10 mic input transformer, so you'll lose some gain and increase noise by using a lower ratio. 1:1 would work well for line input to a 2128 though.

 

[dale116dot7]

The line input transformer could be used backwards (CT gets control voltage) for a vari-mu with semi remote tubes (6ES8 or similar) or maybe for a diode bridge compressor input and maybe even interstage transformer for the same compressors.

 

[pesloth]

Diode bridge compressor sounds really cool! Can you recommend a built?

 

[TwentyTrees]

Diode bridge compressor sounds really cool! Can you recommend a built?

I love my Garash / DIY Studio Toys DB54 (2254-style):
DB54 - 2254 style compressor {update 22.10.19}

You'd need to check the specs of the suggested Carnhills against your Sowters of course.

 

[pesloth]

I love my Garash / DIY Studio Toys DB54 (2254-style):

DB54 - 2254 style compressor {update 22.10.19}

You'd need to check the specs of the suggested Carnhills against your Sowters of course.

Ill look in to that

 

[pesloth]

Can anyone tell me if any of the tranformer types in post #1 would be suitable for putting before my Pro Tools rig?

I would love to have 32 transformer balanced inputs to add color when tracking.

But are they suitable?

 

[anders]

Allen&Heath/Brennell ("AHB") Syncon B consoles modified for broadcasters used Sowter 4757 on almost all outputs, including the direct outputs. The 4757 was Sowter´s replacement for Gardners MU7524 and MU7564. AHB wired 4757 in reverse for line outputs. Sowter developed the 4757 into 3257, later 1715. So yes, you could make a rack of 32 x 4757 transformers connected beetwen console busses/mic-preamps (electronically balanced) outputs and yhe ProTools interface (electronically balanced) inputs. Pass the signals through 4PDT switches for monitoring between 4757 in circuit or bypassed.
The 4757s are hence not used for balancing/trouble-fix purposes, just for adding "some transformer coloring" to recordings. This subtle "effect" may suit some but not all types of signals, depending on recording levels and/or frequency content.

 

[nielsk]

The Sowter bridging line inputs would work good on your Pro Tools inputs, maybe add some color?
They would work great for an API line input (for an EQ or whatever).
Remember the API 500 series are unbalanced input
Very good for balancing unbalanced line inputs (power amps, insert returns, and so on...)