With 2sk170/2sj74 having symmetric drain/source, the tester really has no way of
distinguishing the two pins. Note its measurement of 0.55mA @ 0.37V is consistent
with what you can expect from a 2sj74.
As Andy pointed out, a simple jig is great for Idss and j113 measurements since
you're interested in controlling Vgs/Id.
distinguishing the two pins. Note its measurement of 0.55mA @ 0.37V is consistent
with what you can expect from a 2sj74.
As Andy pointed out, a simple jig is great for Idss and j113 measurements since
you're interested in controlling Vgs/Id.
It’s alive. Drops across R18, R15, R11 as expected. DC/gnd at approx 10v7. 10.29 and 10.31 mA through the 113s, a tad higher than jig (0.3mA). I hope happy days.
Porn to follow tomorrow. The cheap kind, and probably not arousing even for solderofiles. And then a listen. If I can find some headphones 🙂
Cheers,
Andy
Porn to follow tomorrow. The cheap kind, and probably not arousing even for solderofiles. And then a listen. If I can find some headphones 🙂
Cheers,
Andy
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Ready for listening
Following up with a few pics. Managed to sqeeze in the final mounting this morning.
Very happy with almost everything, but as always I have a few things that I know may be improved. But good enough it seems, measures fine voltage and current-wise. Tested with some terrible apple earplugs, and sounds promising. But something else is required to really hear what this baby is good for.
This project I tried to do some things for the first time. As reported earlier, I matched J113s and resistor pairs, and that turned out to work. Really happy with that. I used the same jig / breadboard to pair J74s, also a first for me. Baby steps.
Thanks to Mr. Pass, ZM and many others!
3rd project done, ready for more when time allows
Following up with a few pics. Managed to sqeeze in the final mounting this morning.
Very happy with almost everything, but as always I have a few things that I know may be improved. But good enough it seems, measures fine voltage and current-wise. Tested with some terrible apple earplugs, and sounds promising. But something else is required to really hear what this baby is good for.
This project I tried to do some things for the first time. As reported earlier, I matched J113s and resistor pairs, and that turned out to work. Really happy with that. I used the same jig / breadboard to pair J74s, also a first for me. Baby steps.
Thanks to Mr. Pass, ZM and many others!
3rd project done, ready for more when time allows
Attachments
Andy glad u found Bens post and pix.
Great....its an easy mod...and I use the ACP+ with my HD 650's...excellent results.
For 300 Ohm headphone, add a 36 Ohm resistor at the two positions shown in my picture and change R16 and R17 to 300 Ohm.
2 - 36 ohm
2- 300 ohm
Alex
Great....its an easy mod...and I use the ACP+ with my HD 650's...excellent results.
For 300 Ohm headphone, add a 36 Ohm resistor at the two positions shown in my picture and change R16 and R17 to 300 Ohm.
2 - 36 ohm
2- 300 ohm
Alex
to andy #1803
Hello Andy,
I am pretty sure you will like this preamp/headphonamp a lot!
Cheers
Dirk
Hello Andy,
I am pretty sure you will like this preamp/headphonamp a lot!
Cheers
Dirk
Thanks a lot, guys!
Been running all day. Despite the crappy headphones I can hear real potential. There is no apparent overweight of sugar, but it’s mellow and clear at the same time. Good dynamics too. It is the first piece of hi fi kit I have really enjoyed GNR on, and those recordings need a little help with their harmonics 🙂 Enjoyable so far.
Wrt headphones. Adydula, thank you for the resistor tips. I am currently considering some Grados. Anyone tried Grados with the ACP? The cool thing is they are 32 or 38 ohm in my pricerange 🙂 94-97db/mW. So I figure worth a shot, though I expect most anything to work on this great little big circuit 🙂
Been running all day. Despite the crappy headphones I can hear real potential. There is no apparent overweight of sugar, but it’s mellow and clear at the same time. Good dynamics too. It is the first piece of hi fi kit I have really enjoyed GNR on, and those recordings need a little help with their harmonics 🙂 Enjoyable so far.
Wrt headphones. Adydula, thank you for the resistor tips. I am currently considering some Grados. Anyone tried Grados with the ACP? The cool thing is they are 32 or 38 ohm in my pricerange 🙂 94-97db/mW. So I figure worth a shot, though I expect most anything to work on this great little big circuit 🙂
Andy if your on a budget, take a look at the Senn 600 or 650....they work very well with the ACP +....I have had Grados here but never liked the earpads, very scratchy feeling here...I had the 325i, Hemps ....
Friends, thank you so much for your good advice!
I got a good deal on a new pair of Grado SR120e’s today, so I decided to try them. Impedance fits perfectly at least, and sound quite promising allready.
Guess I’ll be scratching my ears the coming days
I got a good deal on a new pair of Grado SR120e’s today, so I decided to try them. Impedance fits perfectly at least, and sound quite promising allready.
Guess I’ll be scratching my ears the coming days
Power bank as power supply for aca pre
Hi all, is it a pre that can be powered with a power bank 24V 1-2 A?
Hi all, is it a pre that can be powered with a power bank 24V 1-2 A?
Thanks, Vinz!
Sounding better and better. Paired with my Bryston DAC it sounds even better. The DAC can be a bit dry sounding, but nicely smoothed by the ACP. Give me a chime if you have a Pass DAC in surplus
Sounding better and better. Paired with my Bryston DAC it sounds even better. The DAC can be a bit dry sounding, but nicely smoothed by the ACP. Give me a chime if you have a Pass DAC in surplus
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Haha! Who knew it would only be a one-off digital adventure for PL. Well, at least for those of us who where teenagers or gigolos at the time of launch.
Mighty, I was thinking, since you are the master - the real life Zardoz - of DIY Papaland, how about drafting a Mighty Papa-DAC?
Three kids and twin turbo Toyota Supra speed of kids feet in the whole house, is not exactly compatible with turntable adventures right now. Hope I am not alone 🙂
Edit: temporary child free setup in a corner of the house, some class A still while waiting for what’s to come of next power amp amp speaker setup.
Mighty, I was thinking, since you are the master - the real life Zardoz - of DIY Papaland, how about drafting a Mighty Papa-DAC?
Three kids and twin turbo Toyota Supra speed of kids feet in the whole house, is not exactly compatible with turntable adventures right now. Hope I am not alone 🙂
Edit: temporary child free setup in a corner of the house, some class A still while waiting for what’s to come of next power amp amp speaker setup.
Attachments
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This is the first prototype of ZM BabelDAC: at left you have spdif input, at right analog output 😀
Haha! Who knew it would only be a one-off digital adventure for PL. Well, at least for those of us who where teenagers or gigolos at the time of launch.
Mighty, I was thinking, since you are the master - the real life Zardoz - of DIY Papaland, how about drafting a Mighty Papa-DAC?
Three kids and twin turbo Toyota Supra speed of kids feet in the whole house, is not exactly compatible with turntable adventures right now. Hope I am not alone 🙂
Edit: temporary child free setup in a corner of the house, some class A still while waiting for what’s to come of next power amp amp speaker setup.
Papa, with Papateam - they made at least another one digital gizmo, to my knowledge - "digital" amp (ok, not so digital, but some wakoo class, which is same as digital to your truly) ...... though - dunno/can't remember was it commercial product or ended "just" as prototype
There is somewhere pic of it , Pa showing of, while Boyz were at front chamber of his Ark
lemme see can I find it
wasn't issue do I have it, it is always - how it's named
regarding DAC ...... one can do wonder taking as base cheap Topping D10 or even better - D30
toss it in bigger case, remove generic drek after DA chip, go wild to replace it
though, I'm only one ........ maybe in next life I'll grow enough to have one or few Aprentice/s ........... problem is having much more ideas than time to conduct them
photo - courtesy of Pa and Mighty AR2 ( Pa is Mighty by Default and Title)
regarding DAC ...... one can do wonder taking as base cheap Topping D10 or even better - D30
toss it in bigger case, remove generic drek after DA chip, go wild to replace it
though, I'm only one ........ maybe in next life I'll grow enough to have one or few Aprentice/s ........... problem is having much more ideas than time to conduct them
photo - courtesy of Pa and Mighty AR2 ( Pa is Mighty by Default and Title)
