[samsquanch]

I'm about to build a DC-Coupled B1 Buffer for my preamp, the preamp will also contain a 4 input 4 output switcher, which will have the buffer between the in's and outs.  I will also use relays to put a volume pot in the path for when I switch to the output for my power amp.  The question becomes where will the buffer be most effective for the power amp, pre or post the volume pot?  In my head it's after the pot, as this is just how I've always seen gear schematics, pot->circuit.  But which is more impacted by an impedance change, an output (a low impedance) or input (high impedance), it would seem that the ratio of constant impedance (gear input/output) to variable impedance (volume pot) would be better if the pot followed the buffer.  
 
I'm probably over thinking this, and should just put the pot before the buffer and be done with things.
 
Any thoughts or links to reading on the subject are appreciated.

 

[qusp]

yeah well I would say after provided your source can drive the cables and pot without issue.
 
do remember the DCB1 and standard B1 are pretty much for pleasant harmonic colouration, they do not have significant output current, they do not have low output impedance, they do not have very large input impedance either. dont get me wrong I love Nelson's stuff mostly, but while it may have lower output impedance than some tube circuits and the DCB1 in particular is very low noise and has great (though toasty) PSU, it fails pretty badly to provide the functionality that one normally expects of a buffer.

 

[samsquanch]

Ok, after doing some more reading, then re-reading what I posted, I believe I was thinking about things wrong, and yeah, pot then buffer...
 
Interesting what you had to say though, maybe I'll just stick with my current pre:  opamp (unity gain) -> pot -> opamp (unity gain)
 
 
Thanks!

 

[nikongod]

why not:
opamp --->transformer volume control ---> opamp
:evil:

 

[samsquanch]

But that would be just silly... 
 
 
 
I'M ON IT!
 
 
I've got some volume control transformers laying around at work, looks like this boy got himself something to screw around with tomorrow!

 

[qusp]

Quote:

why not:
opamp --->transformer volume control ---> opamp
:evil:

haha awesome! way to fly in the face of 'wisdom' samsquanch

 

[samsquanch]

Quote:

haha awesome! way to fly in the face of 'wisdom' samsquanch

 
Honestly, I don't think there's enough parts here...
 
1:1 transformer input -> tube buffer -> VCT w/ pots for fine adjustment -> DCB1 -> 1:1 transformer output 
 
Let's get stupid!

 

[qusp]

hey with the right transformer you could actually get a low impedance output from the DCB1

 

[nikongod]

A long term dream of mine has been this:
10k:600 ohm transformer
Shunted 2-deck audio pot in balanced config
One of the purpose built balanced opamps. 
10K:600ohm transformer - output. 

 

[samsquanch]

Quote:

A long term dream of mine has been this:
10k:600 ohm transformer
Shunted 2-deck audio pot in balanced config
One of the purpose built balanced opamps. 
10K:600ohm transformer - output. 

 
For about $500 in transformers (at least from Jensen), you've got me currious, what are the intended benefits/results?

 

[nikongod]

Quote:

 
For about $500 in transformers (at least from Jensen), you've got me currious, what are the intended benefits/results?

 
Im kind of obsessed with ground loops, and converting from SE to balanced and back effortlessly. 
And I like transformers. 
 
I have not even bread-boarded it, but I doubt it would cost more than $100 with Edcor transformers. Not really the same as Jensen, but the price is right.