What's wrong with the kiss, boy?

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#28
In the spirit of ZM's suggestion I have been doing the following for the last couple of years. I directly tap the output of the DAC. The signal is on two legs, each riding on DC (equal but opposite polarity between the two legs). This is sent to step up transformer (2:1 voltage gain and reflecting 4:1 decreased impedance). The transformer also has the added bonus of stripping off the DC.

This is led to the pot and B1 buffer (of course). You probably want to increase the pot from the recommended 25k to 50k so the load on the source/DAC (reflected through the transformer) is high. You may need to slap a RC LPF as a reconstruction filter (although the transformer itself may provide some filtering)

You can go crazy choosing a transformer. My inexpensive solutions (in the USA) are Edcor WSM series (about $10-15) or Cinemag (15 series for about $60 or a bifilar for about half that). Jensen has a series 11 model that should also be a candidate but at a higher cost.

Buffers and transformers are fun to play with (as ZM has reminded us).
 
#30
speaking of DACs , I used xformer for differential I/V , with loading (linearisation) strictly on secondary side ;in fact , several db of missing gain was made with discrete SUSY stage , so input impedance was set as of DAC/xformer freq. linearisation loading
 
#31
So dear ZM,
About the low Rout of buffer, do you mean this Pass buffer with jfets paralled? How do you remove the pot?
pass buffer.jpg
 
#33
Diamond Alternates

Zen Mod said:
tnx boyz ...... as I said , I'm in age when I certainly forgot more than I know now .... :clown:

regarding buffer type - I'm working on Diamond buffer , which is going to have similar THD spectra as complementary JFet one , and even better when loaded hard
of course that most important advantage is 100% lesser number of preciousssssss JFets in it :rofl:

I couldn't s...we'll see soon , I'm getting pcbs in few days , will test them as Iron :Pumpkin:
Click to expand...

Curious here on this idea. I'm kinda trying to proto up some alternate buffers for a M2 and a F6 front end and curious to see if there's any new boiled water in Zen Mod... 🙂
 
#37
Zen Mod said:
that one is exact one which I made in my Iron Pre

pot is needed , I believe I drew it on simplified schematic
Click to expand...

ZM since we are on the topic of buffers and transformers

a)do you feel that even a simple buffer like the one above sounds best when supplied with a shunt regulator?
b)do you feel that a transformer or an active sounds better when doing a SE to differential conversion?

Thanks. nash
 
#38
nashbap said:
ZM since we are on the topic of buffers and transformers

a)do you feel that even a simple buffer like the one above sounds best when supplied with a shunt regulator?
b)do you feel that a transformer or an active sounds better when doing a SE to differential conversion?

Thanks. nash
Click to expand...

a) absolutely . others are having different fetishes , I'm having just shunt regs.

and thin wire
and (all ) speakers
and tubes
and transformers
and ...... :rofl:

b) it really depends of several factors , but good xformer when properly fed and properly loaded , is hard to beat in signal energy preservation department.
however , there are electronic solution for that (se to bal) task , but I can vouch only for solutions where two output phases are intrinsically connected , contrary to often used OP based circuits , where existing phase is just flipped with OP and voila ...... you have both legs , but for me they're as from different persons

nothing wrong with Frankenstein , but he's not audio signal :clown:
 
#39
Thanks mighty ZM, I am getting closer.. 🙂
Does anyone know currently available source of shunt regulation PCB? I know there is mesmerized B1 PCB here, but I wonder whether this board can cover paralleled JFets current.
 
#40
ref to your post #31 - you don't need paralleled JFets with that iteration of buffer

what I meant with paralleling is to do that with buffer made of 2SK170 up and 2SK170 down , to achieve same Rout as with complementary type

regarding shunt reg - note that one JFet vertical pair ( whichever sex it is ) is drawing no more than Idss current , which is 6-12mA for BL range

so , practically any shunt reg round is capable to feed that
say that 50mA is good point for that , feeding one channel
everything above that is waste , both of heat and my time for typing :rofl:

edit : I believe I'll have Good Gemini and Iron Pumpkin as kit in time of 1.5 months , with several possible iterations - basically SE or balanced , where balanced is (believe it or not ) SUSY , through xformer unique intrinsic characteristics
 
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