Hi! I have been reading up on the Iron Pumpkin, it seems like a great project! I have read different numbers of the input impedance, maybe with earlier / later iterations. I might have missed something in my reading quest. What would the input impedance of this vegetable animal be (roughly)? I would use it between my 250 ohm (30V) tubed phono pre and a DAC and a FW SIT 3 or 300b tube amplifiers.
sorry, missed this one
Rin is practically value of shunt resistor going from gate of input JFet to gnd
default 100K, can be altered to 220K with no worries ...... except worries about interconnect cable capacitances
tnx to your remarks, I realized that I made omission with snubber arrangement
already edited for future IP Motherboards
again, not of much importance having snubbers, in this case
but, again, we like overkill
OBS: I have not read the tips and trix thread yet, so my questions might be premature, if so, don't spend time answer that which has already been answered.
If we look at Tribute and Intact Audio, their inductance is 150-180Hy and was perhaps designed for passive operation rather than active. So my first questions are:
1. How come yours is only 10Hy ?
2. Is 10Hy enough when in combination with active buffer as in relying on current rather than inductive reserve ?
3. If run in passive mode, Turtle only, would increasing the Hy to 150 be beneficial ?
Reason for asking is this: I plan on using/building custom PASS XA30.8 amplifiers in my audio chain, meaning they become monoblocks (redesigned) besides building Babelfish XA252 as monoblock as well. The reason for s as in multiples is simple: Active filter. I intend to also build around Nelsons active Analog Crossover Network because I want to have the option of listening to a fully active system besides passive.
4. Will my system be best if paired with the active buffer (Iron Pumpkin) ?
If we look at Tribute and Intact Audio, their inductance is 150-180Hy and was perhaps designed for passive operation rather than active. So my first questions are:
1. How come yours is only 10Hy ?
2. Is 10Hy enough when in combination with active buffer as in relying on current rather than inductive reserve ?
3. If run in passive mode, Turtle only, would increasing the Hy to 150 be beneficial ?
Reason for asking is this: I plan on using/building custom PASS XA30.8 amplifiers in my audio chain, meaning they become monoblocks (redesigned) besides building Babelfish XA252 as monoblock as well. The reason for s as in multiples is simple: Active filter. I intend to also build around Nelsons active Analog Crossover Network because I want to have the option of listening to a fully active system besides passive.
4. Will my system be best if paired with the active buffer (Iron Pumpkin) ?
Slagle - cheapest (was 200$, now 300$ for pair) is declared from 20H to 190H, depending of lams stacking arrangement
probably matter of measurement apparatus, but I did measure less than 15H, driven by stage of my choice, in lam. arrangement of my choice
1. because it is enough in context of entire construction; for comparison, Edcor used in various constructions known to us (starting from DEFiSIT/SIT-3, then various concoctions of mine) is fed to 1,5H tap, with buffer having wimpier Cojones than one used in IPumpkin; see:
2. again, Iron Turtle is constructed to be fed from low Rout stage; my directive from very start wasn't to make swiss-knife-good-to-drive-from-wimpy-tube-phono, but to make entire package
3. no passive, as is; also no 150H - simply because making Iron Turtle with 150H would result in Megalodon, not Turtle; bigger core (for size or two), higher Rdc etc. .......... as anything, Turtle is group of compromises, and I did choose this exact group, not any other
4.if you ask me, you can hardly make or buy better; but that's just me, fully biased
probably matter of measurement apparatus, but I did measure less than 15H, driven by stage of my choice, in lam. arrangement of my choice
1. because it is enough in context of entire construction; for comparison, Edcor used in various constructions known to us (starting from DEFiSIT/SIT-3, then various concoctions of mine) is fed to 1,5H tap, with buffer having wimpier Cojones than one used in IPumpkin; see:
2. again, Iron Turtle is constructed to be fed from low Rout stage; my directive from very start wasn't to make swiss-knife-good-to-drive-from-wimpy-tube-phono, but to make entire package
3. no passive, as is; also no 150H - simply because making Iron Turtle with 150H would result in Megalodon, not Turtle; bigger core (for size or two), higher Rdc etc. .......... as anything, Turtle is group of compromises, and I did choose this exact group, not any other
4.if you ask me, you can hardly make or buy better; but that's just me, fully biased
Thanks.
I know the value of inductive attenuation. It is a transformer, as voltage goes down amperage goes up.
Resistors are converters, as voltage goes down, so does amperage and excess energy is converted to heat and thrown out.
Resistive attenuation introduce artificial source compression and that is why signal integrity is lower via resistive.
It doesn't matter if it is in the form of lose resistors or IC (MUSES 72320), same function. Resistive attenuation is best used at full volume which makes them pointless ... LOL
Only inductive or iron based INCREASE micro dynamics at lower listening levels. As you turn down the volume, more current becomes available which is increasing or making sure that the dynamic range is maintained.
I know the value of inductive attenuation. It is a transformer, as voltage goes down amperage goes up.
Resistors are converters, as voltage goes down, so does amperage and excess energy is converted to heat and thrown out.
Resistive attenuation introduce artificial source compression and that is why signal integrity is lower via resistive.
It doesn't matter if it is in the form of lose resistors or IC (MUSES 72320), same function. Resistive attenuation is best used at full volume which makes them pointless ... LOL
Only inductive or iron based INCREASE micro dynamics at lower listening levels. As you turn down the volume, more current becomes available which is increasing or making sure that the dynamic range is maintained.
Mightiness,
maybe a stupid question, but can the amount of gain influence the sound quality of the whole system depending on which power amp is used? I find for example that this vegetable, used with the M2x, sounds better with 8 dB gain than with just 2 dB, at the same volume, of course.
Or is it just me? 🤪
maybe a stupid question, but can the amount of gain influence the sound quality of the whole system depending on which power amp is used? I find for example that this vegetable, used with the M2x, sounds better with 8 dB gain than with just 2 dB, at the same volume, of course.
Or is it just me? 🤪
I believe that you can find complete measurements published in one of threads, done with AP One by my friend
There is difference of course, THD being higher with higher gain setting but - that difference being so small that I believe what you're hearing is not effect of Iron Pumpkin gain setting but rather difference in amp you're using
In fact, I don't believe that, I'm damn certain
ZM, Omnicertain
There is difference of course, THD being higher with higher gain setting but - that difference being so small that I believe what you're hearing is not effect of Iron Pumpkin gain setting but rather difference in amp you're using
In fact, I don't believe that, I'm damn certain
ZM, Omnicertain
in that case, you're able to hear diminutive increase in THD, and you like it
besides playing with gain setting, there is funny (shunt) resistor position on buffer output, designated "LOADING"
its role being exactly that - if you want some Sugar, introduce appropriate valued resistor there and stop changing value when you're happiest
use 1pin sockets, so easy to change
start with 2K2 and go down
leave gain setting where appropriate for system
ZM, Omniaware
besides playing with gain setting, there is funny (shunt) resistor position on buffer output, designated "LOADING"
its role being exactly that - if you want some Sugar, introduce appropriate valued resistor there and stop changing value when you're happiest
use 1pin sockets, so easy to change
start with 2K2 and go down
leave gain setting where appropriate for system
ZM, Omniaware
I enjoyed going "hands on" with an Iron Pumpkin today. Even when my job was just to steady the board while @timkrone soldered some of TO-92 critters home. This has now forced me to actually read about the Pumpkin/Turtle...I think I kind of want one now. This design seems oddly familiar, like "Mighty One" on Groundhog Day or something to that effect.
