Reduction power supply question

[bishop]

Has anyone tried (or thought about) using a K&K Audio cascode (or basic) CCS with their Reduction?  If so, did you have any issues?  How well did it work?  Thanks!

[Paul Birkeland]

The Integration kit adds six constant current sources and two voltage regulators to the Reduction. 

-PB

[bishop]

The Integration looks like a very nice upgrade.  I was just considering some other less expensive alternatives.  Thanks.

[mcandmar]

Its a very basic kit, PCB, couple of transistors, and a trim pot.  From there its up to you to work out the current setting/operating point to run them at.  That is the most important bit, the circuit design/operating point is what you are really buying from BH, the physical parts are inconsequential.

[Doc B.]

You're also buying Camille Cascode Constant Currrent Source from us. It is different than the circuit K&K sells.

[Paul Birkeland]

The Integration looks like a very nice upgrade.  I was just considering some other less expensive alternatives.

The mosfet kits do cost less, as they use fewer parts, but you'll end up needing to trim each CCS individually to set the correct current.  (This takes a battery and another resistor, and some patience)  Mosfets also are higher capacitance devices than BJT's, which can decrease CCS performance at high frequencies. 

[Doc B.]

Just to clarify, we offer no tech support for the installation of the K&K parts.

[bishop]

From there its up to you to work out the current setting/operating point to run them at. 

Understood.  That will take a bit of doing, but might be an interesting undertaking.

[bishop]

Mosfets also are higher capacitance devices than BJT's, which can decrease CCS performance at high frequencies.

But I would be modifying the power supply not the signal chain, so I would expect this to be a non-issue.  Thanks.

[bishop]

Just to clarify, we offer no tech support for the installation of the K&K parts.

Sure, that is to be expected.  That said, if I had a general question about the operational parameters of the Reduction (like what voltage is expect at point X, or what current range is acceptable for point Y), I would assume that sort of question would be answered, right?

[Doc B.]

Yup that info is readily available in the manual. From the numbers there and measurements you can take from the stock circuit you can just Ohm's law your way to what you need.

I don't mean to be a dick about this, and we will happily offer support for the build of the stock Reduction. If you want my tech support to install a CCS I will happily supply it if you buy my stuff. If you buy the K&K parts it seems reasonable that Dave would be the guy to ask about implementation. If he is selling a kit intended to modify one of our products he would know how our product works, I hope.

[Paul Birkeland]

But I would be modifying the power supply not the signal chain, so I would expect this to be a non-issue.  Thanks.

Hmm, I can't quite tell what you would be doing with the CCS's in the power supply...

[bishop]

Hmm, I can't quite tell what you would be doing with the CCS's in the power supply...

So clearly I don't understand how the CCS is implemented then, but that's OK... my thinking was that starting with a simple, inexpensive method of constant current operation would lead to a deeper understanding of things.  Then, if I eventually upgrade to an Integration kit, I will understand and appreciate it better.   

[bishop]

I don't mean to be a dick about this...

Of course... I wasn't thinking that at all. No way to support every idea/mod that comes to your customer's mind.  I was just wondering if anyone had tried another method of employing a CCS.