Suhr Minimix II - complete schematic

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bluesfendermanblues
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Suhr Minimix II - complete schematic

Post by bluesfendermanblues »

This is the full schematic of the Suhr Minimix II. (with a bug in the switch wiring)

As earlier mentioned the US price is only USD 250, so its not worth your while to make a DIY version. The right components (e.g. 1% resistors), line transformers, omron relays, switches, DC|DC converters, jacks and hammond box....you cannot possible beat the price in US.

So buy a real genuin version.

This schemo is only posted in order to show that the Suhr Minimix II is basically a buffer amp and a summing amp - no mumbo jumbo, no phase shifts, just a plain and simple quality product that delivers the goods.
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bluesfendermanblues
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Re: Suhr Minimix II - complete schematic

Post by bluesfendermanblues »

As you can see from the gut shots its a nicely made product.
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bluesfendermanblues
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Re: Suhr Minimix II - complete schematic

Post by bluesfendermanblues »

and more
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Last edited by bluesfendermanblues on Mon Mar 14, 2011 9:53 pm, edited 2 times in total.
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bluesfendermanblues
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Re: Suhr Minimix II - complete schematic

Post by bluesfendermanblues »

And two more
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Structo
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Re: Suhr Minimix II - complete schematic

Post by Structo »

You already took it apart!?

What is the little silver cube? Transformer?
Tom

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bluesfendermanblues
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Re: Suhr Minimix II - complete schematic

Post by bluesfendermanblues »

Structo wrote:You already took it apart!?

What is the little silver cube? Transformer?
Yes, else I couldnt make the schematic :wink:
The small metal box is one of the three transformers. Had to unsolder in order to make correct measurements.
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angelodp
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Make one

Post by angelodp »

You gonna make one? It does not look too difficult.

A
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Structo
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Re: Suhr Minimix II - complete schematic

Post by Structo »

Gottcha.
What do you mean S1 Switch not correctly wired?
Tom

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GatesofDawn67
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Poor Design

Post by GatesofDawn67 »

I cannot believe they put the relay in the summing node of the op amp. Any noise that couples in here will see the total open loop gain of the op amp. The input resistor should go between the relay and the op amp.

The 49.8k's are probably the recommended load for the xformers. They could be wired as shunts and the summer could use 2k input and feedback resistor for lower hiss and less noise pick up.
bluesfendermanblues
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Re: Poor Design

Post by bluesfendermanblues »

GatesofDawn67 wrote:I cannot believe they put the relay in the summing node of the op amp. Any noise that couples in here will see the total open loop gain of the op amp. The input resistor should go between the relay and the op amp.

The 49.8k's are probably the recommended load for the xformers. They could be wired as shunts and the summer could use 2k input and feedback resistor for lower hiss and less noise pick up.
Do you own a minimix II or have you tried one? If so, what hiss and what noise, are you refering to, the MMII is completely noiseless. Dont try to reinvent the wheel ;-) The relays are there in order for you to switch off parallel operation if you use eg a compressor Or eq in the loop.

@angelodp, I have build a clone on a peice of veroboard for my second rack, using the simplified schematic I posted - without xformers and relays - using a simple +/-15v supply. And it is aldo completely noiseless and transperant. :?
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Mark
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Re: Suhr Minimix II - complete schematic

Post by Mark »

The transformers aren't high quality ones, but they are sufficient to do the job. RG Keen uses them in a A/B/Y splitter box he designed. I have this on my to do list. :oops: :oops: :oops: :oops:

http://www.geofex.com/
Yours Sincerely

Mark Abbott
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Re: Suhr Minimix II - complete schematic

Post by bluesfendermanblues »

Mark wrote:The transformers aren't high quality ones, but they are sufficient to do the job. RG Keen uses them in a A/B/Y splitter box he designed. I have this on my to do list. :oops: :oops: :oops: :oops:

http://www.geofex.com/
Yes, I'm sure you can use the Mouser 42TM018-RC for a DIY MM II clone

However, as mentioned before (in the threat about the simplified MM II) you don't need the xformers in order to make a clone. An if you want to use xformers, you only need one in the return patch if want ot be sure not to have ground loops.

As mentioned above I don't use xformers in my clone and it is just as noiseless as the genuine original in my main rack.
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Structo
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Re: Suhr Minimix II - complete schematic

Post by Structo »

So those tiny transformers are just isolation transformers?

What about T3?
Tom

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Drumslinger
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Re: Suhr Minimix II - complete schematic

Post by Drumslinger »

that's what i was thinking Tom. They are used to supress noise in the circuit and possibly with other benefits like transfering power between 2 circuits that are not connected together.
bluesfendermanblues
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Re: Suhr Minimix II - complete schematic

Post by bluesfendermanblues »

Yes, the xformers are just for isolation purposes.

The reason the use 3 is that you can use a stereo jack to connect two effect units - one on tip, one on ring - and eac of the two returns 'get' a xformer.

IF you, however, flick the little switch you can alter the operation to balanced mode instead.

However, using transformers both send an return are IMO way overkill or over engineering. You can avoid ground loops simply by using xformer on the send OR using gound lift on either the send or return jack.
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Last edited by bluesfendermanblues on Thu Mar 17, 2011 3:45 pm, edited 1 time in total.
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