not so easy to calculate ........ one need to include inductive nature of the beast ......
say that you're feeding AVC on top , say that Rout of buffer is 10R (round figure for easy calculus) , say that you're on -6db tap , feeding power amp
transformed Rout of buffer is 2R5 (square of voltage ratio) , add to that 50R of Rdc (half winding) ....... but with simple calculus we can't include mood of Magnetic Goddess
best way to measure it ........ or simply think of it as low enough , and properly waste time on something maximally hedonistic
say that you're feeding AVC on top , say that Rout of buffer is 10R (round figure for easy calculus) , say that you're on -6db tap , feeding power amp
transformed Rout of buffer is 2R5 (square of voltage ratio) , add to that 50R of Rdc (half winding) ....... but with simple calculus we can't include mood of Magnetic Goddess
best way to measure it ........ or simply think of it as low enough , and properly waste time on something maximally hedonistic
ZM is slow , but inevitable ...... 
Iron Pumpkin SE pcb , completed , tested , done (veni vidi vici alea iacta est )
selector , shunt reg(s) , ZM's Diamond buffer , everything on one mono pcb
tomorrow starting with Bal iteration
Iron Pumpkin SE pcb , completed , tested , done (veni vidi vici alea iacta est
)selector , shunt reg(s) , ZM's Diamond buffer , everything on one mono pcb
tomorrow starting with Bal iteration
Attachments
it seems I'm finished with checking of all (pcbs) modules
today - populated and checked balanced Iron Pumpkin electronic module
so , tomorrow taking some proper pictures of all modules , last cosmetic touch-ups of schematics ,transferring them to pictures , preparing rest of graphical documentation .......and opening proper thread
today - populated and checked balanced Iron Pumpkin electronic module
so , tomorrow taking some proper pictures of all modules , last cosmetic touch-ups of schematics ,transferring them to pictures , preparing rest of graphical documentation .......and opening proper thread
Attachments
About a year ago I had 4 PCB made up of the SE version of the Iron Pre and bought all the parts. I then proceeded to put it all in a box and forget about it.
This weekend I opened up the box, built it, and listened...
I am now kicking myself for letting it sit this long - holy moly, this preamp sounds glorious! Absolutely beautiful. I'm truly smiling and pleased, tapping my toes and humming and singing, this will be a fantastic project for so many people.
The PCB works, the revisions will be very minor, the next step is to get an attractive chassis from HiFi2000 and build up the entire preamp.
In the attached photo the relay is being held open by a jumper, I hadn't yet installed the selector switch.
This weekend I opened up the box, built it, and listened...
I am now kicking myself for letting it sit this long - holy moly, this preamp sounds glorious! Absolutely beautiful. I'm truly smiling and pleased, tapping my toes and humming and singing, this will be a fantastic project for so many people.
The PCB works, the revisions will be very minor, the next step is to get an attractive chassis from HiFi2000 and build up the entire preamp.
In the attached photo the relay is being held open by a jumper, I hadn't yet installed the selector switch.
Attachments
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as I told you ...... wait to hear balanced iteration , with full SUSY flavor ..... (which is inherent in xformers from Moses time )
decent selector, decent pot , decent shunt reg , decent local decoupling , decent buffer , decent autoformer ....... what man can expect from that .......
however , I think we agree that Store needs to have smaller and bigger kits - without and with chassis
when properly done , it can compete with gazzilion greenies priced preamps
(Mighty ZM , humble as always)
ya mean - held closed ?
)decent selector, decent pot , decent shunt reg , decent local decoupling , decent buffer , decent autoformer ....... what man can expect from that .......
however , I think we agree that Store needs to have smaller and bigger kits - without and with chassis
when properly done , it can compete with gazzilion greenies priced preamps
(Mighty ZM , humble as always)
ya mean - held closed ?
somebody somewhere asked for Cinemag iteration
yeah , here it is - most probably last and final version
any of these possible to put on pcb:
Edcor PC 600:600
Jensen JT-123-FLCPH
Cinemag CMOQ 4LPC
convenient jumper near each xformer , to kill connection to xformer while setting buffer output offset , and to choose either 6db or 9db gain
that's it , regarding SE iteration
will do the same for Bal , but no provision for changing gain (logically ,technical reasons) , it'll stay 6db
as usual , big tnx to Pa - he gave me info about pin/windings arrangement of Cinemag , couldn't find it in their datasheet
yeah , here it is - most probably last and final version
any of these possible to put on pcb:
Edcor PC 600:600
Jensen JT-123-FLCPH
Cinemag CMOQ 4LPC
convenient jumper near each xformer , to kill connection to xformer while setting buffer output offset , and to choose either 6db or 9db gain
that's it , regarding SE iteration
will do the same for Bal , but no provision for changing gain (logically ,technical reasons) , it'll stay 6db
as usual , big tnx to Pa - he gave me info about pin/windings arrangement of Cinemag , couldn't find it in their datasheet
Attachments
Last edited:
I have build it using cinemag cmoq-4 wired for 12dB gain but get only 2.5 times that! I grounded the yellow wire and using secound primary winding so twisted red and orange wire as signal input, twisted braun and grey wire also blue and violet and green is output wire to RCA??? Any thought?
