I used gorilla sticky double sided, to board then to ( I sliced the piece of foam the tube came with in half) foam, then used pressure to indent the tube into the foam and slobbered. Took additional piece of two faced and attached other side of tube. I also have, stud-1/2" sticky rubber-stud, for mounting to chassis.....chassis will be lined with dynOmat.
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I solved all my microphonic issues and sudden bursts of noise by sandwiching the tube between pieces of "anti-slip" silicone pads sold as "earthquake" resistant slip mats from Daiso. I originally slipped a piece of this pad underneath the tube. It did not really stop the noise bursts. As a last ditch attempt I added a piece of the material to completely cover the glass upper surface of the tube. I have had no issues since. The Korg tube runs cool so the pad on the top surface will not result in an overheated device. I leave the preamp all the time.
I also made isolated nylon standoffs by cutting each in half and gluing a small piece of the earthquake resistant pad between the two halves. This is more complaint than using regular rubber isolating bushes.
You can source similar in your country. Cutting the material is a PIA.
google daiso earthquake resistant mat
I also made isolated nylon standoffs by cutting each in half and gluing a small piece of the earthquake resistant pad between the two halves. This is more complaint than using regular rubber isolating bushes.
You can source similar in your country. Cutting the material is a PIA.
google daiso earthquake resistant mat
Thanks Zen Mod for that article. I am moving in that direction but slowly. Have one of my Bryston 2Bs gain reduced to 23db but loud for me is still around 9 on the b1k attenuator so I wind up reducing the level from iTunes and put the B1K to 12 o’clock. I would like to hear your/anyone’s opinion on using the digital, I think, volume control in iTunes. Thanks
B1 issue - defective trimpot?
Hello All,
This is my first post. First, I want to thank Mr. Pass for sharing his wealth of knowledge and making it possible for audio electronics fans like myself to get our hands dirty, learn about the nuances of audio circuitry, and gain the satisfaction of churning out a cool piece of gear. I have built the ACA, a class D, and some stomp boxes. I just completed the B1 and it looks good - however I do have an issue.
~*~*~*~*~
Before explaining, here are the vitals:
T1: 24.02v
T3: 22.67v
T4: 9.20v
T5: .62vdc
T6: .67vdc
T7: 10.00v
T8: 10.00v
The NuTube lights up fine with both channels responding to the trimpot adjustments.
I powered up, and waited for about 30 minutes...No smoke, high-pitched hum that dissipated pretty quickly. All pretty much as expected.
~*~*~*~*~
The issue:
Left channel seems fine
Right channel is virtually non-existant. When I adjust the trimpot, there is a loud scratchy sound that emanates regardless of the volume. As noted above, the NuTube responds to the adjustments - so the pot is working somewhat correctly. However no sound (extremely faint).
At first pass I suspected that the pot had oxidation, but I am not so sure. I re-flowed solder into the pins of the pot, no change. I also re-soldered the NuTube. One thing to note is that when soldering (during the build) a couple JFETS came loose and fell out. I do not think I mixed them up as I have taken voltage measurements across the "good" channel and affected channel and all of the Q1 and Q2 JFETS are uniform.
I suspect that I have a bad trimpot, but wanted to post my situation in case I am missing something.
Full disclosure: the testing equipment I have currently is a multimeter, so I can't provide too much detail that an oscillator might achieve.
Thanks in advance,
JP
Hello All,
This is my first post. First, I want to thank Mr. Pass for sharing his wealth of knowledge and making it possible for audio electronics fans like myself to get our hands dirty, learn about the nuances of audio circuitry, and gain the satisfaction of churning out a cool piece of gear. I have built the ACA, a class D, and some stomp boxes. I just completed the B1 and it looks good - however I do have an issue.
~*~*~*~*~
Before explaining, here are the vitals:
T1: 24.02v
T3: 22.67v
T4: 9.20v
T5: .62vdc
T6: .67vdc
T7: 10.00v
T8: 10.00v
The NuTube lights up fine with both channels responding to the trimpot adjustments.
I powered up, and waited for about 30 minutes...No smoke, high-pitched hum that dissipated pretty quickly. All pretty much as expected.
~*~*~*~*~
The issue:
Left channel seems fine
Right channel is virtually non-existant. When I adjust the trimpot, there is a loud scratchy sound that emanates regardless of the volume. As noted above, the NuTube responds to the adjustments - so the pot is working somewhat correctly. However no sound (extremely faint).
At first pass I suspected that the pot had oxidation, but I am not so sure. I re-flowed solder into the pins of the pot, no change. I also re-soldered the NuTube. One thing to note is that when soldering (during the build) a couple JFETS came loose and fell out. I do not think I mixed them up as I have taken voltage measurements across the "good" channel and affected channel and all of the Q1 and Q2 JFETS are uniform.
I suspect that I have a bad trimpot, but wanted to post my situation in case I am missing something.
Full disclosure: the testing equipment I have currently is a multimeter, so I can't provide too much detail that an oscillator might achieve.
Thanks in advance,
JP
Thank you for your quick response, Nelson. Yes, I think the fets are okay. I just did a quick resolder of the caps and resistors along the signal path, I still have the issue. Each turn in the pot just makes this loud static.
I will make my way through the circuit tonight to see what I can find. My voltage at Q1 is 12.03v (versus the left channel of 11.27v at the source). Interestingly the Q2 is 1.597v at the source in the affected channel (versus .524v in the left at the source of Q2) in the passive path. I am not sure if that is something to note, but relatively that is a bit of a difference. I'll go through the signal path more closely tonight.
Thanks again for the response,
Joe
(btw, I grew up in Sacramento and got my first audio equipment at Sun Stereo on Arden Way - next to Pizza and Pipes. I definitely remember the days of Threshold...though I was 11-12, I was a reader of Audio and Stereo Review. My best friend had ESS Tempests. Wonderful days. But with DIY, it is a new golden age)
I will make my way through the circuit tonight to see what I can find. My voltage at Q1 is 12.03v (versus the left channel of 11.27v at the source). Interestingly the Q2 is 1.597v at the source in the affected channel (versus .524v in the left at the source of Q2) in the passive path. I am not sure if that is something to note, but relatively that is a bit of a difference. I'll go through the signal path more closely tonight.
Thanks again for the response,
Joe
(btw, I grew up in Sacramento and got my first audio equipment at Sun Stereo on Arden Way - next to Pizza and Pipes. I definitely remember the days of Threshold...though I was 11-12, I was a reader of Audio and Stereo Review. My best friend had ESS Tempests. Wonderful days. But with DIY, it is a new golden age)
Fixed! It was a bad connection in Q1, the source pin actually...voltage at the source went down to 10.7v on the right Q1 (from over 12v). Now it is singing and sounds great. I will tweak to correct any microphonic issues and fortunately there's a lot of info here I'll mine (and will share any findings not found).
Thanks again,
Joe
Thanks again,
Joe
First diy build completed today.
I completed the build today, I was trying to fit it into a Hammond 1590J guitar pedal box, so it will go with my small system. The tube was lifted and facing the front, the six small holes let the light shines through, so I don't need a bright LED. Turned it on and it worked! This is my first diy project and it was easy enough to build and it sounds quite good compare to my other tube preamps. This can be my summer preamp when it's too hot to use real tubes. Very happy with the outcome!
Thinking about trying better components like potentiometer, capacitors and power supply later. I am thinking about trying the F6 build, but not sure how to figure out the psu.
I completed the build today, I was trying to fit it into a Hammond 1590J guitar pedal box, so it will go with my small system. The tube was lifted and facing the front, the six small holes let the light shines through, so I don't need a bright LED. Turned it on and it worked! This is my first diy project and it was easy enough to build and it sounds quite good compare to my other tube preamps. This can be my summer preamp when it's too hot to use real tubes. Very happy with the outcome!
Thinking about trying better components like potentiometer, capacitors and power supply later. I am thinking about trying the F6 build, but not sure how to figure out the psu.
An externally hosted image should be here but it was not working when we last tested it.
Attachments
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p90fan - congrats on the successful troubleshooting! Enjoy!
archishih - very cool! Nicely done. re: the F6 - 6L6 has an excellent build guide for the universal PSU. An equally good alternative, IMO, is the Aleph J build guide for noobs blog posted by a forum member. It goes into the build a bit more noob friendly and walks through the entire PSU build. Same PSU for F6 and other FW amps. Mainly, if you have questions, post. Links.
diyAudio Power Supply Circuit Board v3 illustrated build guide
Introduction: What Is This and Who Is It For?
Sagen - Beautiful. Love the matting idea. Nice!
Enjoy the music, everyone!
archishih - very cool! Nicely done. re: the F6 - 6L6 has an excellent build guide for the universal PSU. An equally good alternative, IMO, is the Aleph J build guide for noobs blog posted by a forum member. It goes into the build a bit more noob friendly and walks through the entire PSU build. Same PSU for F6 and other FW amps. Mainly, if you have questions, post. Links.
diyAudio Power Supply Circuit Board v3 illustrated build guide
Introduction: What Is This and Who Is It For?
Sagen - Beautiful. Love the matting idea. Nice!
Enjoy the music, everyone!
It sounds even better today. I had the top off yesterday, and it was very sensitive, and the hum persisted.
The non-vented top, must have improved this from the first generation batch - because it is much quieter. I turned it on this AM and left it on all day. I do not think it is placebo, this really has "broken in" a bit. Michael Hedges' Aerial Boundaries is just singing through this beautifully.
Thanks again Mr. Pass! And thank you very much to 6L6 for the build guides (I also relied on this for the ACA build a couple years ago). The high granularity of the photos and detailed instructions make this all possible and fun for relative diy newbies such as myself.
The non-vented top, must have improved this from the first generation batch - because it is much quieter. I turned it on this AM and left it on all day. I do not think it is placebo, this really has "broken in" a bit. Michael Hedges' Aerial Boundaries is just singing through this beautifully.
Thanks again Mr. Pass! And thank you very much to 6L6 for the build guides (I also relied on this for the ACA build a couple years ago). The high granularity of the photos and detailed instructions make this all possible and fun for relative diy newbies such as myself.
p90fan - congrats on the successful troubleshooting! Enjoy!
archishih - very cool! Nicely done. re: the F6 - 6L6 has an excellent build guide for the universal PSU. An equally good alternative, IMO, is the Aleph J build guide for noobs blog posted by a forum member. It goes into the build a bit more noob friendly and walks through the entire PSU build. Same PSU for F6 and other FW amps. Mainly, if you have questions, post. Links.
diyAudio Power Supply Circuit Board v3 illustrated build guide
Introduction: What Is This and Who Is It For?
Sagen - Beautiful. Love the matting idea. Nice!
Enjoy the music, everyone!
Thank you ItsAllInMyHead, will look into the PSU and the Aleph J.
