Taking what you are doing with IRON PRE to an earlier part of the chain ...
I have been wondering just how much gain one can get from an autoformer between two complementary buffers. I will keep wondering until someone tells me since I have no idea. The question being how far can you go before it does work very well.
I am thinking (beware) of a phono stage using this idea. One would think the buffers would allow much easier use of an LR or LCR equalization. Thing an input tranformer, typical MC 1:32 (I use a very low output cartridge) into a buffer then an autoformer - 1:20 (?) another buffer then to the RIAA equalizer of whatever configuration then to another buffer - an autoformer (1:20) then to the final buffer.
Could there be anything good about this or is it hopeless?
I have been wondering just how much gain one can get from an autoformer between two complementary buffers. I will keep wondering until someone tells me since I have no idea. The question being how far can you go before it does work very well.
I am thinking (beware) of a phono stage using this idea. One would think the buffers would allow much easier use of an LR or LCR equalization. Thing an input tranformer, typical MC 1:32 (I use a very low output cartridge) into a buffer then an autoformer - 1:20 (?) another buffer then to the RIAA equalizer of whatever configuration then to another buffer - an autoformer (1:20) then to the final buffer.
Could there be anything good about this or is it hopeless?
like anything in this world ....... too much of good thing is ...... simply no more good
as you already have some experience - with transformers , magic is there only if everything is in order - properly sized cojones to drive it , then appropriate amount of gain ( or whatever is primary - gain or impedance transfer etc)
that especially demands proper strategy - using xformers moderately , trying to exploit all benefits and gain none of drawbacks (each time you multiply amplitude , you're loosing bandwidth and linearity , not mentioning accumulation of phase issues - that's simple physics....... same applies to buffers - if you can skip one , that's certainly better than having it in chain
don't fall in any of well known critical categories (tube junkies , especially ...... and yes - I'm one of them , even if sort of closet one for last decade) , and insist on just one approach as best
choose what's best for exact location in chain , do not alter chain to include what you prefer from some romantical reasons
ok - 'nuff generalizations
decent SUT - decent gain stage with steady input impedance and not critical input capacitance .... with decent Rout
then , if needed something as buffer to properly shake LR(C) Eq net
then decent gain stage with steady input impedance and not critical input capacitance .... with decent Rout ........ and you're done
simple ............. but not so simple
I think I'm gonna put some Metglas cores in good use in some near period
dreaming about proper LR phono stage for last decade .....
well , as soon I close full circle with Iron Pumpkin(s) 😉
as you already have some experience - with transformers , magic is there only if everything is in order - properly sized cojones to drive it , then appropriate amount of gain ( or whatever is primary - gain or impedance transfer etc)
that especially demands proper strategy - using xformers moderately , trying to exploit all benefits and gain none of drawbacks (each time you multiply amplitude , you're loosing bandwidth and linearity , not mentioning accumulation of phase issues - that's simple physics....... same applies to buffers - if you can skip one , that's certainly better than having it in chain
don't fall in any of well known critical categories (tube junkies , especially ...... and yes - I'm one of them , even if sort of closet one for last decade) , and insist on just one approach as best
choose what's best for exact location in chain , do not alter chain to include what you prefer from some romantical reasons
ok - 'nuff generalizations
decent SUT - decent gain stage with steady input impedance and not critical input capacitance .... with decent Rout
then , if needed something as buffer to properly shake LR(C) Eq net
then decent gain stage with steady input impedance and not critical input capacitance .... with decent Rout ........ and you're done
simple ............. but not so simple
I think I'm gonna put some Metglas cores in good use in some near period
dreaming about proper LR phono stage for last decade .....
well , as soon I close full circle with Iron Pumpkin(s) 😉
How well I know it is not so simple! But it never stops me from thinking I can find some short cut to good sound.
My motivation with that scheme was its simplicity in conception without any awareness of the pitfalls. I wanted a "free lunch" phono stage. I can make those buffers and anyone can wire them up the transformers ...
I would love to see/hear your take on a phono stage, ZM!
Take care,
My motivation with that scheme was its simplicity in conception without any awareness of the pitfalls. I wanted a "free lunch" phono stage. I can make those buffers and anyone can wire them up the transformers ...
I would love to see/hear your take on a phono stage, ZM!
Take care,
ZM, do I understand that I can also order ( in time) the super special AVC's and the PCB's from you, in order to build a balanced Iron Pumpkin?
How is this project going?
Will the store have PCB's for Iron Pre soon or do you expect it will take some months?
( desperate looking for a balanced preamp 😀 )
-small batch of Metglas cores - ordered ystrdy
-pcbs for Iron Pumpkin SE, Iron Pumpkin , Iron Turtle SE, Iron Turtle and switch pcb for them - ordered ystrdy
hope to have them all in few weeks time
will have zillion of relays and important semis in quantity in same time
so , pictures of finished monsters are near .......
as it seems - Store will be second with Iron Pre SE and Iron Pre
-pcbs for Iron Pumpkin SE, Iron Pumpkin , Iron Turtle SE, Iron Turtle and switch pcb for them - ordered ystrdy
hope to have them all in few weeks time
will have zillion of relays and important semis in quantity in same time
so , pictures of finished monsters are near .......
as it seems - Store will be second with Iron Pre SE and Iron Pre
I believe it'll certainly going to be a first time I would actually build something of my own construction (well , made in sort of series, not just one unique piece) for my self .......
name it - Babelfish J , Babelfish J2 ,Pumpkin , PSM LS ........ when I'm finished with actual "package" , something new is always more interesting than actually investing time in building it for my own use
so , I'm having two Koans , both dreamed by Mithrandir ... so I'm really not needing better or other amps in daily use ,while few (mostly no-gainers) "preamps" are all I need for my setups
but , this one (Iron P & T) .... I really never dreamed that one day I will make my own AVC based stage .... and it came by coincidence , playing with autoformers , making two custom preamps from start of the thread .....
funny - acquisition of all puzzles needed to slip in , was more tiring and troublesome than construction itself
name it - Babelfish J , Babelfish J2 ,Pumpkin , PSM LS ........ when I'm finished with actual "package" , something new is always more interesting than actually investing time in building it for my own use
so , I'm having two Koans , both dreamed by Mithrandir ... so I'm really not needing better or other amps in daily use ,while few (mostly no-gainers) "preamps" are all I need for my setups
but , this one (Iron P & T) .... I really never dreamed that one day I will make my own AVC based stage .... and it came by coincidence , playing with autoformers , making two custom preamps from start of the thread .....
funny - acquisition of all puzzles needed to slip in , was more tiring and troublesome than construction itself
Balanced Pre...
I'm With Walter W, need a balanced Pre for Pass F4 Dual Mono. On quest, build all diy Pass Amps. More amps more Preamps. No end!!! H.
I'm With Walter W, need a balanced Pre for Pass F4 Dual Mono. On quest, build all diy Pass Amps. More amps more Preamps. No end!!! H.
for F4 bridged , you need either BA3 FE Bal , or Pumpkin , or SY's tube one
Iron Pumpkins are simply not made with that gain and amplitude as goal
neither Iron Pre(s) , hopefully soon available through Store
Iron Pumpkins are simply not made with that gain and amplitude as goal
neither Iron Pre(s) , hopefully soon available through Store
And than, you didn't even count in the amps I still want to build in my head....it's a true addiction😱
J2, F7, XA25, SIT1, 50W BAF2015 Schade Amp, UGS-preamp aaaaargh.....😉
J2, F7, XA25, SIT1, 50W BAF2015 Schade Amp, UGS-preamp aaaaargh.....😉
well , I did build almost all , at least representatives of each family
almost all with schmtc known to public and few of them with schmtc still unpublished .....
I betcha my M2 Koan will sing with Cousin Pre ......
correction - it sings ....
almost all with schmtc known to public and few of them with schmtc still unpublished .....
I betcha my M2 Koan will sing with Cousin Pre ......
correction - it sings ....
Preamp Balanced
ZM; yes, building BA3 as preamp. 6L6 Build Thread. Your pre's will work with the other builds Pass can't seem to stop designing (for us). Maybe for 'new toyz for greedy boyz' he has planned to release in '6 months'. Have not found Pumpkin info as yet. Will continue search. Thanks, H.
ZM; yes, building BA3 as preamp. 6L6 Build Thread. Your pre's will work with the other builds Pass can't seem to stop designing (for us). Maybe for 'new toyz for greedy boyz' he has planned to release in '6 months'. Have not found Pumpkin info as yet. Will continue search. Thanks, H.
posts #331 ad #345
Turtle is AVC package , Iron Pumpkin is accompanying electronics (reg plus buffer) , together they're (again) Iron Pumpkin
one without suffix is balanced ,while one with SE suffix is ........ SE, what else
Turtle is AVC package , Iron Pumpkin is accompanying electronics (reg plus buffer) , together they're (again) Iron Pumpkin
one without suffix is balanced ,while one with SE suffix is ........ SE, what else
forgot to say - 6L6 is da Man to ask these questions ; prototype is still in his yard
ZM, went to your sig. You have nice sig! Plenty for study. Always seem to miss things. Search does not come up with such treasures. Thanks for map! H.
to run the iron pumpkin with the optimal (lowest) attenuation, it would be nice to have the gain switchable on the frontplate. (party an normal😀) Since the Turtle will be directly behind the frontplate there wouldn´t be ecessivly long cables neccesary.
Does anyone have an insight if the switch (maybe classic switch with just 2 positions) should be “break-before-make” or “make-before-break” ones.
I guess it´s make -before -break and the former attenuation setting it´s than kind like bridged/shorted in the continuous autoformer winding?
stefan
Does anyone have an insight if the switch (maybe classic switch with just 2 positions) should be “break-before-make” or “make-before-break” ones.
I guess it´s make -before -break and the former attenuation setting it´s than kind like bridged/shorted in the continuous autoformer winding?
stefan
An externally hosted image should be here but it was not working when we last tested it.
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logic is that Iron Turtle is near as possible to back plate , where outputs are
OK , sort of compromise , because you need Iron Pumpkin close to inputs , while you also need Iron Turtle close to outputs
however , purpose of these jumper fields is to set adequate gain for your system and to forget it , and I'm vary of routing these lines to any sort of front plate situated switch ...........maybe Elna or other really good quality rotary switch , placed near Turtle , with extending shaft from front plate ..........
however - I took great care of switching arrangement for Turtle , using Takamisawa goldies for all switching purposes , finding them better than most expensive rotary switches ; this jumper field is somewhat weaker point , but if someone is willing , after initial setting , one can even solder pins together instead of jump(er)ing them
.......... NB that manufacturers are using those even on MC level positions, so ZM really doesn't need to be too hysteric
OK , conclusion ...... I'm simply doubting that you'll need to change gain in daily use
and , if you really need that , 2 sections/5 positions quality rotary switch near Turtle is all you need
one section for Gain A group , second section for Gain B group , with 0,2,4,6,8db positions
OK , sort of compromise , because you need Iron Pumpkin close to inputs , while you also need Iron Turtle close to outputs
however , purpose of these jumper fields is to set adequate gain for your system and to forget it , and I'm vary of routing these lines to any sort of front plate situated switch ...........maybe Elna or other really good quality rotary switch , placed near Turtle , with extending shaft from front plate ..........
however - I took great care of switching arrangement for Turtle , using Takamisawa goldies for all switching purposes , finding them better than most expensive rotary switches ; this jumper field is somewhat weaker point , but if someone is willing , after initial setting , one can even solder pins together instead of jump(er)ing them
.......... NB that manufacturers are using those even on MC level positions, so ZM really doesn't need to be too hysteric OK , conclusion ...... I'm simply doubting that you'll need to change gain in daily use
and , if you really need that , 2 sections/5 positions quality rotary switch near Turtle is all you need
one section for Gain A group , second section for Gain B group , with 0,2,4,6,8db positions
yes, you are right (of course 🙂, i planned it diagonal to the power trannie and ended up in the front therefore. will change that.
and you´re wise also, i virtually used it a bit and did not found me fiddling too much in the gain settings. So i plan to use dip switches in the back and probably don´t use them in the end 😀
tnx
st.