I was mistaken. There is apparently a attenuation section and a gain section. The Passlabs XP-30 does not use the gain section according to Wayne Colburn.
From the review of the Passlabs XP-30 in Stereophile:
"The volume control, also carried on a small daughterboard, is based on a Muses NJU72320 integrated circuit. Although I am an unrecovered collector of datasheets, this chip was new to me; I asked Wayne Colburn about it. "It is part of the NJR Muses line from an in-house audiophile in Japan. They use copper lead frames and laser-trim the part. The designer of these parts came from Japan and gave samples to Nelson and myself to try and they ended up in the XP-30. I run the NJU72320 on ±15 volts so it has a large overload margin. I really like this part as it has no op-amps in it—I only used the front, attenuation section of the chip and not the gain setting section. We didn't use the Muse line op-amp—a discrete circuit is simpler and performs better with higher current and voltage." "
Hi Bassivus,
I don't know how this volume control compares to Muses, because I have not tried a Muses yet ... but I am using a volume control (bought on eBay) that looks exactly like the one you linked to. Using it as an attenuator for my Aikido build. It sounds very transparent (better than an Alps Blue) and works flawlessly. And it is remote-controlled, and has four-way source switching, as well.
Best regards,
Claas
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Hi Bassivus,
I don't know how this volume control compares to Muses, because I have not tried a Muses yet ... but I am using a volume control (bought on eBay) that looks exactly like the one you linked to. Using it as an attenuator for my Aikido build. It sounds very transparent (better than an Alps Blue) and works flawlessly. And it is remote-controlled, and has four-way source switching, as well.
Best regards,
Claas
Thanks! It's good to know the quality of those! I'll build the trial version with simple pot and if I like the sound I'll invest in one of those attenuator/switches.
I was able to get Diana working recently and this is one channel of the Nutube preamp at 11.4v.
Can one of you wizards help tell me what this means? I think I know but at the expense of sounding dumb, I'm just going to ask
Thanks,
Kevin
BTW - It sounds awesome and I have a couple things to do before I post some pics.
Can one of you wizards help tell me what this means? I think I know but at the expense of sounding dumb, I'm just going to ask
Thanks,
Kevin
BTW - It sounds awesome and I have a couple things to do before I post some pics.
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Brief update
RS have sent me a part order of tubes, some more are on the way. I should have PM'ed everyone for their address and about delivery cost:
if I have missed you please PM me.
if QWERTY! is bundling yours in with the PCB please let me know I will forward them to him.
When I said first come first served, there are plenty of tubes you just may have to wit for the second delivery which is likely to be the end of this week/start of next.
RS have sent me a part order of tubes, some more are on the way. I should have PM'ed everyone for their address and about delivery cost:
if I have missed you please PM me.
if QWERTY! is bundling yours in with the PCB please let me know I will forward them to him.
When I said first come first served, there are plenty of tubes you just may have to wit for the second delivery which is likely to be the end of this week/start of next.
I was able to get Diana working recently and this is one channel of the Nutube preamp at 11.4v.
Can one of you wizards help tell me what this means? I think I know but at the expense of sounding dumb, I'm just going to ask
Thanks,
Kevin
BTW - It sounds awesome and I have a couple things to do before I post some pics.
See post 994. It explains which setting yields 2nd harmonic.
Hi BassivusThanks! It's good to know the quality of those! I'll build the trial version with simple pot and if I like the sound I'll invest in one of those attenuator/switches.
I have built a preamp for a friend using the same kit. It pay attention to a few things:
1) when changing from 64 to 65 dB there could be a high pitch sound while music is playing because there is no delay to prevent relay contact swithcing wrong sequence. Also, happens from 96 to 97 dB and so on....There is a thread on that issue. I could provide a reasonable fix by adding a new board creating delay between relays and preventing all of them at the same time. I have a few spare if you need one.
2) the circuit tends to be sensible to EMI. My friend had an issue with a defective remote control extender (radio wave) where the volume changed by itself.... once he turned off the defective device it has fixed the issue.
3) relay mechanical clicking can be annoying...so I have build a sound isolation cage using damping material inside a wood box.
But the sound is quite good.
Fab
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Here are some pics of the final build. I went a little overboard on this one so it's a bit of overkill but I'm sure nobody minds that.
The PSU is a Sigma 11 24v regulated supply.
The volume control is a Khozmo remote controlled attenuator
I got the Nutube and carrier board from Pete Millet
The input selector is the Select-2 from Tubecad
I still need to glue the plexiglass inserts on the front panel but haven't gotten there yet but it will be smoked glass on the front.
A couple things I need to work out - My input selector pops. The other thing is that I have an Intel NUC -> DAC -> preamp and I can hear a slight buzz when the CPU is working. It wasn't there before but now I can hear it. I can't hear it while playing music but can when nothing is playing. Probably some sort of grounding thing.
Anyways, it sounds great. I have it hooked up to an F5 and it makes the bass much stronger (didn't expect that) and almost 3 dimensional but has a slight echo in my ears on the low end.
Thank you Mr. Pass !
Kevin
The PSU is a Sigma 11 24v regulated supply.
The volume control is a Khozmo remote controlled attenuator
I got the Nutube and carrier board from Pete Millet
The input selector is the Select-2 from Tubecad
I still need to glue the plexiglass inserts on the front panel but haven't gotten there yet but it will be smoked glass on the front.
A couple things I need to work out - My input selector pops. The other thing is that I have an Intel NUC -> DAC -> preamp and I can hear a slight buzz when the CPU is working. It wasn't there before but now I can hear it. I can't hear it while playing music but can when nothing is playing. Probably some sort of grounding thing.
Anyways, it sounds great. I have it hooked up to an F5 and it makes the bass much stronger (didn't expect that) and almost 3 dimensional but has a slight echo in my ears on the low end.
Thank you Mr. Pass !
Kevin
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Looks great
How did you get the lettering on the front panel?
David
I'm guessing mine will be ready in about 6 months
Here is my version.
Does sound very good. Have a VAC (tube) preamp and the sound is very similar - the B1 Nutube maybe being a bit more articulate and having tighter bass. It definitely is in par, even with the basic switching power supply. No critical listening done yet though.
A big thanks, Nelson!
Does sound very good. Have a VAC (tube) preamp and the sound is very similar - the B1 Nutube maybe being a bit more articulate and having tighter bass. It definitely is in par, even with the basic switching power supply. No critical listening done yet though.
A big thanks, Nelson!
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Oh yes… no ringing here - only if one taps on the Nutube directly. Took Nelsons advice and used hot glue. Lifted the Nutube up a bit and made a kind of a hotglue acustical felt sandwich. Seems to work fine.
And Still.. didn't fasten the pcb to the cassis directly. Also put Felt underneath the PCB and just the wires holdin the PCB in place.
And Still.. didn't fasten the pcb to the cassis directly. Also put Felt underneath the PCB and just the wires holdin the PCB in place.
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