value of volume pot is having all with Rout of sources upstream, B1 buffer itself not caring at all about vol pot value
Log is what you need for volume, that's physiology related; you can use linear pot shunted to result in log law; search on Rod Eliot's web for "better volume control"
After dealing with AVC, I'm not looking back at resistive attenuators, when max sound quality is of interest
Log is what you need for volume, that's physiology related; you can use linear pot shunted to result in log law; search on Rod Eliot's web for "better volume control"
After dealing with AVC, I'm not looking back at resistive attenuators, when max sound quality is of interest
have a read of the last few pages
its not 100% confirmed as i have no means of testing distortion but it looks good on the graph and sounds good to my ears
Mezmerize B1 Buffer Preamp
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So I am almost done with my B1 (Jfets and board from PassDIY). This is going to be the buffer/switch for a tube amp which already has a pot. I am planning on a bypass switch on the b1 for the volume control, any issue doing this?
Also I am considering transformers on the B1, I read ZM somewhere talking about jfet gender and needing to be careful? Was this wit or wisdom? both or nether? I had no idea I thought most electronics where non-binary. Can someone clarify?
Also I am considering transformers on the B1, I read ZM somewhere talking about jfet gender and needing to be careful? Was this wit or wisdom? both or nether? I had no idea I thought most electronics where non-binary. Can someone clarify?
Red here, https://www.diyaudio.com/forums/ana...iometer-passive-preamplifier-post3157081.html ,that higher value pots combined with input capacitance of interconnect from source form a low pass filter.
Therefore 20k log is optimal for the B1.
Looks like I could still trust my ears!
Therefore 20k log is optimal for the B1.
Looks like I could still trust my ears!
Indigent Audio
My advise, use a 20 to 25k log as the input pot to B1.
If not at least connect a 25k resistor to ground and feed the 1k gate resistor on top of it so that you maintain a 25k input impedance.
The jfets you got will be in Idss matchedpairs. If so do try not to separate them
My advise, use a 20 to 25k log as the input pot to B1.
If not at least connect a 25k resistor to ground and feed the 1k gate resistor on top of it so that you maintain a 25k input impedance.
The jfets you got will be in Idss matchedpairs. If so do try not to separate them
Excellent post, but it deals with using only a potentiometer as a 'passive pre-amp'.
If you take your B1 out of the chain and wire up a 20k pot in its place, then you could compare the difference to your ears.
If you take your B1 out of the chain and wire up a 20k pot in its place, then you could compare the difference to your ears.
Red here, https://www.diyaudio.com/forums/ana...iometer-passive-preamplifier-post3157081.html ,that higher value pots combined with input capacitance of interconnect from source form a low pass filter.
Therefore 20k log is optimal for the B1.
Looks like I could still trust my ears!
Therefore 20k log is optimal for the B1.
Looks like I could still trust my ears!
ItsAllInMyHead
Read here http://hifisonix.com/wordpress/wp-content/uploads/2015/01/UBx.pdf in page6, that the best value for input vol.control of jfet buffer is between 10k to 20k.
Read here http://hifisonix.com/wordpress/wp-content/uploads/2015/01/UBx.pdf in page6, that the best value for input vol.control of jfet buffer is between 10k to 20k.
That is the post I said was nice. I am not disagreeing, but looking for further context from your point of view. Perhaps explain why 20k is optimum for the B1 vs. 10k if you are only taking into consideration the sentence quoted above re: the low pass filtering. 10k would be better, yes?
Hi All
Thanks for the helpful replies. Especially the reference to the Korg thread. I've read the first 40 or so pages and developed square eyes AND a major headache! LOL. What I need from the thread is a practical description of how to select the J112 s and associated resistor. Is this information amongst the 500+ pages? If so, I'll keep myself busy over Xmas. If not, I think my best solution may well be a second board and FETs from PASSdiy...
Rgds
Thanks for the helpful replies. Especially the reference to the Korg thread. I've read the first 40 or so pages and developed square eyes AND a major headache! LOL. What I need from the thread is a practical description of how to select the J112 s and associated resistor. Is this information amongst the 500+ pages? If so, I'll keep myself busy over Xmas. If not, I think my best solution may well be a second board and FETs from PASSdiy...
Rgds
Additionally: I started ploughing through the Mesmerise thread (thanks Glenn) and came across a reference to LSK170s available in DIYA store. Is a matched quad set of these all I actually need?
The diyaudio store sells matched quads of LSK170's for $29 Linear Systems Matched JFETs – diyAudio Store
They are grade B which should fall between 6 - 12 ma.
edit: oh this was already discovered.....
Tony.
They are grade B which should fall between 6 - 12 ma.
edit: oh this was already discovered.....
Tony.
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Isn't it a good idea to have two more Diyaudio stores one in UK and one in Singapore?
High cost of postage could be avoided.
Items in high demand could be dispensed from these.
High cost of postage could be avoided.
Items in high demand could be dispensed from these.
@ Srian
Yes two more DiyAudio shops are good idea.
One in Singapore or Hong Kong and one in continental Europe : France, Germany or Italy.
Maybe Modushop in Italy can handle DiyAudio kit's , pcb´s and components distribution business ? 🙂
Yes two more DiyAudio shops are good idea.
One in Singapore or Hong Kong and one in continental Europe : France, Germany or Italy.
Maybe Modushop in Italy can handle DiyAudio kit's , pcb´s and components distribution business ? 🙂
Three more stores? I suspect that would increase overhead by 3x, and so the retail prices would have to be increased by 3x. 😀 😀 😀
Postage (Something out of the control of the store) is almost assuredly cheaper...
Postage (Something out of the control of the store) is almost assuredly cheaper...
+ 1 zillion my vote for 2picoDumbs be the big Boss of DiyAudio shop division in Australia a country=continent 😉 Hahaha
Three more stores? I suspect that would increase overhead by 3x, and so the retail prices would have to be increased by 3x. 😀 😀 😀
Postage (Something out of the control of the store) is almost assuredly cheaper...
Yes 3 more stores = good for DiyAudio business.
Easy buy for much more Diyers , incrase dynamic speed of sales,
less taxes and lower shipping costs. All Winners
DiyAudio shop division by Italian ModuShop for Europe ?
What think the Big Bosses Team Direction ? 🙂