I don't care
just searching for similar triples , one up , one down
so - 3 in triple so-so similar (in 10-15%)
then pairing two triples in 10%
good enough for me , trimpots will take care of difference , while final difference between triples will influence only TempCo , but that one anyway being so superior to complementary buffer
just searching for similar triples , one up , one down
so - 3 in triple so-so similar (in 10-15%)
then pairing two triples in 10%
good enough for me , trimpots will take care of difference , while final difference between triples will influence only TempCo , but that one anyway being so superior to complementary buffer
Iron Pumpkin SE final schematics
long time-ish , but realized it in best way possible ......
regarding Iron Turtle part , no change , but due to lucky find of still current production Toshiba JFets , I was able to make final iteration of buffer stage
so , already sent replacement boards to ppl previously equipped with earlier ones and now is time to publish proper set of schematics
xformer prescribed - 30Vct to 36Vct , minimum 150mA , one per channel , to preserve dual mono arrangement
or - if you're able to get custom one , use one with two sets of 30Vct (to 36Vct) secondaries , 300mA minimum
reg set to 12V both rails , programmed current in reg CCS is 60mA , while buffer Iq is 21mA , so plenty of leeway
selector relays are powered locally from own pcb , each channel independently , so front mounted 6position/2 section rotary switch is best way to handle that , resulting in separated electrical circuits
Iron Turtle relay selector circuit - just route one secondary to controller pcb (30V or 18Vac , whatever) , it will be floating and no interference to audio part of shebang
long time-ish , but realized it in best way possible ......
regarding Iron Turtle part , no change , but due to lucky find of still current production Toshiba JFets , I was able to make final iteration of buffer stage
so , already sent replacement boards to ppl previously equipped with earlier ones and now is time to publish proper set of schematics
xformer prescribed - 30Vct to 36Vct , minimum 150mA , one per channel , to preserve dual mono arrangement
or - if you're able to get custom one , use one with two sets of 30Vct (to 36Vct) secondaries , 300mA minimum
reg set to 12V both rails , programmed current in reg CCS is 60mA , while buffer Iq is 21mA , so plenty of leeway
selector relays are powered locally from own pcb , each channel independently , so front mounted 6position/2 section rotary switch is best way to handle that , resulting in separated electrical circuits
Iron Turtle relay selector circuit - just route one secondary to controller pcb (30V or 18Vac , whatever) , it will be floating and no interference to audio part of shebang
Attachments
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Iron Pumpkin (Bal) final schematics
electrically pretty much the same as SE , except doubled buffer , increased programmed current to ~100mA , and added relay and few parts to have possibility of SE to Bal conversion , thus enabling any number of SE inputs you want
electrically pretty much the same as SE , except doubled buffer , increased programmed current to ~100mA , and added relay and few parts to have possibility of SE to Bal conversion , thus enabling any number of SE inputs you want
Attachments
in a meantime , I made one SE iteration for my buddy Ninja (nick from Baby DiyA)
find enclosed some randomly taken pics , as surrogate to properly made pcb shots ......... which I'm going to make hopefully soon and post here
NB that nothing really changed in overall approach and concept of Iron Pumpkin
what I got with JFet iteration (vs. previous Diamond buffer iteration) is increased input impedance and superior output offset behavior in temp. and time domain
hopefully..... no - really slightly better sound , even if penultimate iteration was damn good , without any false modesty (of which is Mighty ZM anyway not capable )
find enclosed some randomly taken pics , as surrogate to properly made pcb shots ......... which I'm going to make hopefully soon and post here
NB that nothing really changed in overall approach and concept of Iron Pumpkin
what I got with JFet iteration (vs. previous Diamond buffer iteration) is increased input impedance and superior output offset behavior in temp. and time domain
hopefully..... no - really slightly better sound , even if penultimate iteration was damn good , without any false modesty (of which is Mighty ZM anyway not capable )
Attachments
