Rich,
Congratulations on another successful build. Neat work!
Also good to know that the Aleph J is rocking it with this preamp even with the lowish sensitivity LS50s.
6L6 never runs out of helpful advice for the DIY community. As our Australian friends would say "The man is a bloody legend". 😀
Can you point me to the post discussing the masking tape technique or elaborate a bit? I am currently working on a Wayne BA 2018 preamp, but have the Nutube B1 preamp parts and would like to give it a shot some time.
And you enjoy the music!
Congratulations on another successful build. Neat work!
Also good to know that the Aleph J is rocking it with this preamp even with the lowish sensitivity LS50s.
6L6 never runs out of helpful advice for the DIY community. As our Australian friends would say "The man is a bloody legend". 😀
Can you point me to the post discussing the masking tape technique or elaborate a bit? I am currently working on a Wayne BA 2018 preamp, but have the Nutube B1 preamp parts and would like to give it a shot some time.
And you enjoy the music!
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Here is the link to 6L6’s excellent B1 Nutube preamp build guide:
B1 with Korg Nutube - diyAudio Guides
B1 with Korg Nutube - diyAudio Guides
Quote
6L6 never runs out of helpful advice for the DIY community. As our Australian friends would say "The man is a bloody legend".
+1 for 6L6...
French copying the Aus...'Cet homme est une légende' 🙂
6L6 never runs out of helpful advice for the DIY community. As our Australian friends would say "The man is a bloody legend".
+1 for 6L6...
French copying the Aus...'Cet homme est une légende' 🙂
he's having plenty of time, while on AutoPilot
(ZM, knowing everything about flying, as is the case with everything else
)
(ZM, knowing everything about flying, as is the case with everything else
)
Rich - nice build! Looks great.Is that a PEC pot? What values did you use for the coupling capacitors?
Aleph J can run any low-impedance load you can throw at it, AJ just happily chugs along. 😀
Thanks.
The volume pot is a 50k audio taper Cosmos Tocos pot that ClaudeG recommends.
“COSMOS TOCOS Potentiometer RV24YG 20S 15A503 x2 A50kΩx2 A50K 50K 24mm Japan”
Input signal caps: .22uF/400V Panasonic ECQP PP film/foil
Middle signal caps: 2uF/250V Axon True Cap metallized PP film
Output signal caps: 4.7uF/50V Black Gate N non-polar electrolytic
I finally found a use for these Black Gate N caps I bought several years ago from Sonic Craft when Black Gate caps were phasing out. Both measured at 4.47 uF and 4.48 uF using my LCR meter.
My B1
r1Hello,
thought I'd share my take on the B1 w Korg. Standard build with homemade enclosure, internal wiring is Duelund DCA.
Setup: Wadia 121 into the B1, Parasound A23 amp, KEF LS50 speakers and a homemade sub.
My opinion: blown away. Transparency, micro detail, placement/soundstage all took a big step. There's something very inviting and RIGHT about the sound now, and and and, well, I guess y'all know what I mean. Here's a very big, heartfelt Thank You to `Mr. Pass!
I like it so much, I have decided to build another (for reasons I really want 4 channel volume control, so I'll build a dual-stereo pre-amp), but with upgraded parts. Be fun to see if I hear a difference. Some searching trough here will probably put me on the right track, but if somebody already has a BOM of upgraded parts, yes please.
Below some pics.
r1Hello,
thought I'd share my take on the B1 w Korg. Standard build with homemade enclosure, internal wiring is Duelund DCA.
Setup: Wadia 121 into the B1, Parasound A23 amp, KEF LS50 speakers and a homemade sub.
My opinion: blown away. Transparency, micro detail, placement/soundstage all took a big step. There's something very inviting and RIGHT about the sound now, and and and, well, I guess y'all know what I mean. Here's a very big, heartfelt Thank You to `Mr. Pass!
I like it so much, I have decided to build another (for reasons I really want 4 channel volume control, so I'll build a dual-stereo pre-amp), but with upgraded parts. Be fun to see if I hear a difference. Some searching trough here will probably put me on the right track, but if somebody already has a BOM of upgraded parts, yes please.
Below some pics.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Congratulations
Very nice wood enclosure Vomisa. Looking forward to your next B1 Nutube project.
This preamp is very musical and engaging. The Duelund DCA wire is a nice touch. I used the DCA20GA wire myself. I used it in my other Pass DIY amps: the Sony VFET amp and the Aleph J I completed last month. Everything plays well together, and it comes down to whether I want to listen to a complementary Class A amp or a single ended Class A amp. Tough choices, I know.
This preamp is very musical and engaging. The Duelund DCA wire is a nice touch. I used the DCA20GA wire myself. I used it in my other Pass DIY amps: the Sony VFET amp and the Aleph J I completed last month. Everything plays well together, and it comes down to whether I want to listen to a complementary Class A amp or a single ended Class A amp. Tough choices, I know.
Nasty surprise
Just listening to Hans Zimmer 'Live in Prague' following a week of excellent music from my B1Korg. This lovely device really likes playing Blues music by the way.
Then, a loud snap - like a fridge clicking on the mains line, only much, much louder - followed by a diminishing ringing sound and the left channel is gone.
I've opened up the case and removed the eraser from the top of the Nutube (It hadn't been particularly microphonic, I was just covering bases). There's no glow from the left side of the Nutube. I've checked the voltages:
T1 = 24.17v
T2 = 23.37v
T3 = 22.58v
T4 = 9.41v
T5 = 9.5v (both T5 & T6 were in the 0.6v range when I set it up last week)
T6 = 0.719v
T7 = 9.53v (it had been set to 11.45v, the same as T8)
T8 = 11.45v
There are no visible burnt-out components or odours. The soldering was all checked last week when I was chasing down a previous error (a reversed 10uF capacitor on the right channel). It had been playing beautifully up until that point.
Can anyone help please?
Just listening to Hans Zimmer 'Live in Prague' following a week of excellent music from my B1Korg. This lovely device really likes playing Blues music by the way.
Then, a loud snap - like a fridge clicking on the mains line, only much, much louder - followed by a diminishing ringing sound and the left channel is gone.
I've opened up the case and removed the eraser from the top of the Nutube (It hadn't been particularly microphonic, I was just covering bases). There's no glow from the left side of the Nutube. I've checked the voltages:
T1 = 24.17v
T2 = 23.37v
T3 = 22.58v
T4 = 9.41v
T5 = 9.5v (both T5 & T6 were in the 0.6v range when I set it up last week)
T6 = 0.719v
T7 = 9.53v (it had been set to 11.45v, the same as T8)
T8 = 11.45v
There are no visible burnt-out components or odours. The soldering was all checked last week when I was chasing down a previous error (a reversed 10uF capacitor on the right channel). It had been playing beautifully up until that point.
Can anyone help please?
@SR
Did you change a new one the reverse polarity 10uF or just soldered back in right polarity?
It have a chance this cap went wrong.
I've read again your post, and I realized the left channel damaged.
Did you change a new one the reverse polarity 10uF or just soldered back in right polarity?
It have a chance this cap went wrong.
I've read again your post, and I realized the left channel damaged.
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Hi Deenoo,
Thanks for the reply. I replaced both of the 10uF capacitors at that point of the circuit with Silmic II of the same value. The error had been on the right channel though.
Thanks for the reply. I replaced both of the 10uF capacitors at that point of the circuit with Silmic II of the same value. The error had been on the right channel though.
Hi van0718,
That's already been replaced with the Silmic II I mentioned above. The original one was blown so it went in the bin.
Deenoo,
Still not fixed unfortunately. I can read a schematic and solder, but I'm useless with diagnostics.
That's already been replaced with the Silmic II I mentioned above. The original one was blown so it went in the bin.
Deenoo,
Still not fixed unfortunately. I can read a schematic and solder, but I'm useless with diagnostics.
@ SuppersReady
Left channel T5 = 9.5V that tooo much , need to be in 0.6V range +-(0.05)V.
Could you verify visualy if inside of Nutube filament wire string is not broken on the left side ?
Left channel T5 = 9.5V that tooo much , need to be in 0.6V range +-(0.05)V.
Could you verify visualy if inside of Nutube filament wire string is not broken on the left side ?
The tube cathode will not glow if the tube is not in bias. If the filament is broken
then it shouldl measure as open with a multimeter.
then it shouldl measure as open with a multimeter.
Thanks for the cold solder tips a week or two ago. Had a chance to sit down for a few hours today, fix those solders, test PSU (check!) and stuff/solder the rest of the board and "floated" Korg tube (tip - slice the tube packing material thin for a shim)! Solders look good - just like those in the Sixties YouTube training video recommended! Damn power diode is still not functioning so not sure what's up there. But making headway. Appreciate you all for the help. Sneak preview - what I'm using to isolate the board is novel and yet to be reported but looks promising!