Well, origin thread is here : Iron Pumpkin(s) and other smaller vegetable animals
If nothing else, read at least first several posts on linked page , to grasp enough info about concept itself.
This one having two purposes :
-placing all necessary info about final iteration,
-trying to layout clearer picture of what's fuss about,
-with edits of this first post - making comprehensive list of tips and tricks and funny fine details , and answering on any clever or dumb question you'll possibly have ......either here or further in thread
(3 purposes then , not two
)
edit at 22.05.2020. short how-to-do for Iron Pumpkin SE, referencing to post #2:
do not connect buffer output to Turtle
maximize trimpot R36 (measure across R39 to confirm max value)
R37 position is irrelevant for now
if you're sure that you connected everything properly, just power it on
set positive and negative rails to +/-12Vdc , with trimpots R9 and R10
power off, place DVMdc crocs across R34, power On then fiddle with R36 to set 20mV across R34, then fiddle with R37 to set 0mV DC offset at output
do everything the same with other channel, connect outputs of buffers to Turtle, enjoy
If nothing else, read at least first several posts on linked page , to grasp enough info about concept itself.
This one having two purposes :
-placing all necessary info about final iteration,
-trying to layout clearer picture of what's fuss about,
-with edits of this first post - making comprehensive list of tips and tricks and funny fine details , and answering on any clever or dumb question you'll possibly have ......either here or further in thread
(3 purposes then , not two
)edit at 22.05.2020. short how-to-do for Iron Pumpkin SE, referencing to post #2:
do not connect buffer output to Turtle
maximize trimpot R36 (measure across R39 to confirm max value)
R37 position is irrelevant for now
if you're sure that you connected everything properly, just power it on
set positive and negative rails to +/-12Vdc , with trimpots R9 and R10
power off, place DVMdc crocs across R34, power On then fiddle with R36 to set 20mV across R34, then fiddle with R37 to set 0mV DC offset at output
do everything the same with other channel, connect outputs of buffers to Turtle, enjoy
Last edited:
Perfect place for Iron Pumpkin SE set of informative files
OK ....... you already read Origin Thread , so you know that Iron Pumpkin SE package is comprised of two mono pcbs , and one Iron Turtle module , where two Metglas-cored AVCs are sandwiching one pcb , with plenty of Takamisawa relays ...... operated by rotary switch ..... there is a wide flat cable between switch pcbs and Turtle
Channel pcbs contains relay input selector, Good Gemini bipolar shunt regs and extra funny zillion small JFets buffer.
Selector Takamisawa relays are operated with second rotary switch - Lorlin 2section/6 position ( shorting or MBB) , so two tinier flat cables are going from switch to channel pcbs ( one cable per channel)
set of pics :
OK ....... you already read Origin Thread , so you know that Iron Pumpkin SE package is comprised of two mono pcbs , and one Iron Turtle module , where two Metglas-cored AVCs are sandwiching one pcb , with plenty of Takamisawa relays ...... operated by rotary switch ..... there is a wide flat cable between switch pcbs and Turtle
Channel pcbs contains relay input selector, Good Gemini bipolar shunt regs and extra funny zillion small JFets buffer.
Selector Takamisawa relays are operated with second rotary switch - Lorlin 2section/6 position ( shorting or MBB) , so two tinier flat cables are going from switch to channel pcbs ( one cable per channel)
set of pics :
Attachments
Perfect place for Iron Pumpkin set of informative files
So call it either Iron Pumpkin Bal or just Iron Pumpkin - it is not having SE in name .....
Also made of two mono channel pcbs , difference to SE being one more buffer, simply because it is needed for additional phase
Iron Turtle for balanced - each Metglas cored AVC having two bobbins (one per phase) , connected in pure differential mode (contrary to some other AVCs around , using one xformer per phase , so no possibility of intrinsic Supersymmetric operation of differential iron
Also - each AVC is having own relay pcb , but two channels are stacked vertically , practically taking same space as SE Turtle
same switches and flat cables as for SE iteration
additional relay (6-th) on channel pcb is for case that you want to use arbitrary number of SE inputs ; when SE input is chosen , additional relay is energized , so connection between negative buffer output and negative AVC coil is cut , ensuring that non-modulated negative buffer is not acting as virtual GND for its coil ...... which is now modulated from his twin - positive coil , thus we still have full balanced/differential output
set of schm/pics:
(last one - proper input pads labeling - for guys recently getting my pcbs with old, still buggered silkscreen ; sorry guys - it's already corrected for next batch of pcbs)
So call it either Iron Pumpkin Bal or just Iron Pumpkin - it is not having SE in name .....
Also made of two mono channel pcbs , difference to SE being one more buffer, simply because it is needed for additional phase
Iron Turtle for balanced - each Metglas cored AVC having two bobbins (one per phase) , connected in pure differential mode (contrary to some other AVCs around , using one xformer per phase , so no possibility of intrinsic Supersymmetric operation of differential iron
Also - each AVC is having own relay pcb , but two channels are stacked vertically , practically taking same space as SE Turtle
same switches and flat cables as for SE iteration
additional relay (6-th) on channel pcb is for case that you want to use arbitrary number of SE inputs ; when SE input is chosen , additional relay is energized , so connection between negative buffer output and negative AVC coil is cut , ensuring that non-modulated negative buffer is not acting as virtual GND for its coil ...... which is now modulated from his twin - positive coil , thus we still have full balanced/differential output
set of schm/pics:
(last one - proper input pads labeling - for guys recently getting my pcbs with old, still buggered silkscreen ; sorry guys - it's already corrected for next batch of pcbs)
Attachments
Iron Turtle set of schmtcs
oh yeah ... this one was tricky one ..... but am I satisfied with final result ...... you can bet
may I remind you ..... 24 position rotary switches , even if made by Most Beautiful Chinese Virgins only in Full Moon nights - each one is dissasembled , greased (some old and fancy graphite based grease , good for Stagecoaches and my switches) and assembled , thus expecting at least 15 years of proper use ....... two sections are connected in parallel
oh yeah ... this one was tricky one ..... but am I satisfied with final result ...... you can bet
may I remind you ..... 24 position rotary switches , even if made by Most Beautiful Chinese Virgins only in Full Moon nights - each one is dissasembled , greased (some old and fancy graphite based grease , good for Stagecoaches and my switches) and assembled , thus expecting at least 15 years of proper use ....... two sections are connected in parallel
Attachments
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Should I post some fresh measurements ....
OK , my buddy Zeljkor ( as known on Baby DiyA) recently acquired AP1 Dual Domain ( or whatever) , and he was interested in having fun with Iron Pumpkin SE
as soon I manage to make another balanced , we'll arrange AP session for that one , too
so - set of measurements follows :
OK , my buddy Zeljkor ( as known on Baby DiyA) recently acquired AP1 Dual Domain ( or whatever) , and he was interested in having fun with Iron Pumpkin SE
as soon I manage to make another balanced , we'll arrange AP session for that one , too
so - set of measurements follows :
Attachments
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Now zillion of pics about assembly of channel pcbs
I'm really getting tired of upload routine
anyway - pcbs in question were for balanced Iron Pumpkin ; will post detailed instructions for setting both SE and balanced in forst post of thread later ...... for know you know the drill - parts smallest in height first , then taller ones , then taller ones ........
I'm really getting tired of upload routine
anyway - pcbs in question were for balanced Iron Pumpkin ; will post detailed instructions for setting both SE and balanced in forst post of thread later ...... for know you know the drill - parts smallest in height first , then taller ones , then taller ones ........
Attachments
