Well, all solder joints were reflowed. Tubes still green...
I am not a scientific, but there is some logic to help me.
- All caps are good, new silmics. (Do these caps here make a difference in SQ?)
- All resistors have good quality and are new.
- The nutubes are new. They may have one problem, but it will be the last thing to check, but anyway,
- All voltage points are ok.
- Trimmers work.
Whatever the problem is, there must be a faulty part, but I'd say it is not one fet, because the issue is in stereo, so two fets would have something wrong. I don't like coincidences, but is not impossible.
For me, the next step is to check the resistors that are not in double mono, and if the green color persists, I would take out all the other resistors, because I might have done a mistake with the values. Then, I'd check the Nutubes.
Oh, I will check first my order from Mouser, to see if all resistors values are the same as they are in the manual.
I am not a scientific, but there is some logic to help me.
- All caps are good, new silmics. (Do these caps here make a difference in SQ?)
- All resistors have good quality and are new.
- The nutubes are new. They may have one problem, but it will be the last thing to check, but anyway,
- All voltage points are ok.
- Trimmers work.
Whatever the problem is, there must be a faulty part, but I'd say it is not one fet, because the issue is in stereo, so two fets would have something wrong. I don't like coincidences, but is not impossible.
For me, the next step is to check the resistors that are not in double mono, and if the green color persists, I would take out all the other resistors, because I might have done a mistake with the values. Then, I'd check the Nutubes.
Oh, I will check first my order from Mouser, to see if all resistors values are the same as they are in the manual.
are they (resistors) color-coded , or you have some fancy ones ?
Pa once told me that Dale are terrific resistors - they have value written with numbers
Pa once told me that Dale are terrific resistors - they have value written with numbers
Maybe a picture of the amp which also shows input/output connections could tell something?
Do you have another preamp you switch in......and then everything is ok?
Which power amp do you use?
Do you have another preamp you switch in......and then everything is ok?
Which power amp do you use?
Finally, it is not out of the equation that I have a problem in the psu and the board is receiving to much noise, and I will have to send a botle of wine to MEPER.
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Keep going, you'll find the problem. I thought I was pretty good with an iron, too, until I found a problem with a cold solder joint...
Zen Mod, I don't know why I did not buy RN55, they are very very good and as you say, they have the value writen on it.
Pa is right, (if I have permission to call Pa when I speak about Mr Nelson).
MEPER, I will post a clear photo of the board. I have to re activate casimages.com (pay some more...), then extract a link to post here.
Pa is right, (if I have permission to call Pa when I speak about Mr Nelson).
MEPER, I will post a clear photo of the board. I have to re activate casimages.com (pay some more...), then extract a link to post here.
I prefer Romanee-Conti …..maybe vintage 2005 could do it...…. 😀
How will you check if PSU is noisy? DMM set to AC?
R1 depends on the current source Jfet Q2, but it typical figure.
What voltage do you have across it?
What voltage do you have across it?
The buffer was connected to a chinese TPA3116 amp board.
I should have it connected it to a toroid with 18VA but the toroid has 9VA.
There is a linear psu in between of course!
But what's the point? The tubes are green when the buffer is alone...not connected to the amp.
"How will you check if PSU is noisy? DMM set to AC?" No, It was in DC, that's after filter, caps, just to read 24V. I can make another simple psu. Diodes, big cap LT7824, litle cap
Nelson :
Near Nutube :
left, R1 = 1,8V right, R1 = 1,8V
left Q2 - 9,5V right Q2 - 9,7V
Near Trimmers :
left, R1 = 1V right, R1 = 1,6V
left Q2 - 9,7V right, R1 = 10,4V
Across T1 - 0,824V; across T2 - 0,824V; across T3, 3,2V
Voltage in Q2 is measured between left and right leg
I should have it connected it to a toroid with 18VA but the toroid has 9VA.
There is a linear psu in between of course!
But what's the point? The tubes are green when the buffer is alone...not connected to the amp.
"How will you check if PSU is noisy? DMM set to AC?" No, It was in DC, that's after filter, caps, just to read 24V. I can make another simple psu. Diodes, big cap LT7824, litle cap
Nelson :
Near Nutube :
left, R1 = 1,8V right, R1 = 1,8V
left Q2 - 9,5V right Q2 - 9,7V
Near Trimmers :
left, R1 = 1V right, R1 = 1,6V
left Q2 - 9,7V right, R1 = 10,4V
Across T1 - 0,824V; across T2 - 0,824V; across T3, 3,2V
Voltage in Q2 is measured between left and right leg
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I made another psu with a big toroid 18Vsecondary, one mudorf 22000μf/25V cap, schottky diodes, 24V TO220 regulator. 100μf/25V Kaisei cap in the nutube board input.
Nutubes still green.
All resistors are measuring well.
Nutubes still green.
All resistors are measuring well.
Polaron, just curious about what your music source might be? When I initially got my Nutube B1 up and running I used my iPhone headphone jack output feeding the B1 which went into a portable music dock and it sounded horrible. I couldn’t even put the volume on my iPhone volume up past half way without the output sounding very harsh. I was very upset that something might be wrong even though all of the measurements were well within the numbers Nelson suggested in his write up on the Nutube project. I had HUGE relief when I tried it feeding my M2x with my CD player as my source. Then it was all grins and a glass of wine while I enjoyed some music.
Hi JSA1971, I used to have a lot of hifi stuff before, like Naim CDS, all the cd players from 47 Labs, tube amps, olive amps, you name it. Many years before I sold everything. I was out of the hifi scene.
Recently I build a Soekris dam1121 and now I am building the psu for the Soekris dam1921 that I bought a few weeks ago. It will joind the Aleph3 that I am finishing too. As tools, I have an old Koala cd from Gold Note and a very old Arcam from the 90's. I bought it last year for 30 euros. I also have a few other amps, nothing special. The Nutube had a grainy sound with both cd's.
But the important thing is that the tubes are green, even when the buffer is not connected to the cd's. When the sound is not grainy, when it is not pianos for example, when it is percussions, I can "see" how good this thing is, I have no doubts.
Recently I build a Soekris dam1121 and now I am building the psu for the Soekris dam1921 that I bought a few weeks ago. It will joind the Aleph3 that I am finishing too. As tools, I have an old Koala cd from Gold Note and a very old Arcam from the 90's. I bought it last year for 30 euros. I also have a few other amps, nothing special. The Nutube had a grainy sound with both cd's.
But the important thing is that the tubes are green, even when the buffer is not connected to the cd's. When the sound is not grainy, when it is not pianos for example, when it is percussions, I can "see" how good this thing is, I have no doubts.
Voilà, some images!
Waiting for a resistance 10K pot.
Someone in the family says it is green, someone says it is blue...
Waiting for a resistance 10K pot.
Someone in the family says it is green, someone says it is blue...
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http://www.imageshotel.org/images/polaron/dsf2208.jpg
I will connect it to one of my dacs that have no buffer output.
I remember when I connected my K buffer to my Koala cd, it was not terrific, because the K cd has an output buffer and the sound was saturated. May be that's aht's happening today. I will report later today.
What worries me noww is to have only 1volt in R1, (left/high) in the board.
I will connect it to one of my dacs that have no buffer output.
I remember when I connected my K buffer to my Koala cd, it was not terrific, because the K cd has an output buffer and the sound was saturated. May be that's aht's happening today. I will report later today.
What worries me noww is to have only 1volt in R1, (left/high) in the board.
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#2477 : yes , it's almost impossible to post it smaller 
120px × 79px, 1.7 KB
make it 1200xsomething , and it'll show as needed
120px × 79px, 1.7 KB
make it 1200xsomething , and it'll show as needed
http://www.imageshotel.org/images/polaron/dsf2208.jpg
I will connect it to one of my dacs that have no buffer output.
I remember when I connected my K buffer to my Koala cd, it was not terrific, because the K cd has an output buffer and the sound was saturated. May be that's aht's happening today. I will report later today.
What worries me noww is to have only 1volt in R1, (left/high) in the board.
I think you should read the part of discussion on potentiometer(and the lack of it) /input, posted earlier in this thread...
Hi Bassivus,
Can you tell me where is that part of the discussion? This threat is very big.
Thanks.
Can you tell me where is that part of the discussion? This threat is very big.
Thanks.
Hi there. I’m not able to get a stable voltage at T8. After trying to set to 9.5V it’s now fluctuating between 8.5 to 10V... All good at T7 with a very stable 9.5V. I’m wondering if the crooked “frame” on the right channel of my Nutube is more important than I thought? See attached photo. Any suggestions?
