Will work beautifully. 
Yes, you can put it in the same box, although I've never used a caged SMPS in a similar project and have no way to know if it will be quiet or not. (Although it will likely be fine )
I would absolutely try it first, and if it works, wonderful! If not, then try a different approach.
Yes, you can put it in the same box, although I've never used a caged SMPS in a similar project and have no way to know if it will be quiet or not. (Although it will likely be fine
)I would absolutely try it first, and if it works, wonderful! If not, then try a different approach.
My Korg Nutube housed in the DCG3 preamp box makes a cracking noise whenever I switch on/off my hall fans regulator switch/knob. This makes a loud noise during playback. How do I get rid of this as this happens in the entire living hall fans only and not any other electrical equipments being switched on/off. Before installing the Korg in this box there was absolutely no interference in the playback.
B1 Korg mods to Millett headphone amp
Just throwing a FYI out there:
I went back and changed out both the front end input buffer voltage divider resistors and the NuTube plate resistors on my Pete Millett NuHybrid headphone amplifier. The change was from Pete's 475K to Papa's B1 Korg recommended 332K. Then I did some listening and settled on around 10 VDC on the plates (a bit less 2nd harmonic than Papa's 9.5 VDC for the B1 Korg). Big improvement to my ears over Pete's values.
Then I tried replacing the original 2N3904 NPN transistor input buffers with J113 JFETS in a follower and constant current source configuration identical to the B1 Korg DIY store J113 circuit (properly matched, selected and current limited to about 8 mA) but did I not like the imaging (!).
Both the original BJT and the JFET lnput configs yield an inverted signal at the headphones. No way to easily reverse polarity at the output due to most headphones using a common negative for the L and R connections. Apparently the JFET front end with inverted polarity at the transducers is not a good combo.
I may try inverting the signal polarity at the input with some 1:1 isolation transformers I have left over from another project. Keep you posted.
Just throwing a FYI out there:
I went back and changed out both the front end input buffer voltage divider resistors and the NuTube plate resistors on my Pete Millett NuHybrid headphone amplifier. The change was from Pete's 475K to Papa's B1 Korg recommended 332K. Then I did some listening and settled on around 10 VDC on the plates (a bit less 2nd harmonic than Papa's 9.5 VDC for the B1 Korg). Big improvement to my ears over Pete's values.
Then I tried replacing the original 2N3904 NPN transistor input buffers with J113 JFETS in a follower and constant current source configuration identical to the B1 Korg DIY store J113 circuit (properly matched, selected and current limited to about 8 mA) but did I not like the imaging (!).
Both the original BJT and the JFET lnput configs yield an inverted signal at the headphones. No way to easily reverse polarity at the output due to most headphones using a common negative for the L and R connections. Apparently the JFET front end with inverted polarity at the transducers is not a good combo.
I may try inverting the signal polarity at the input with some 1:1 isolation transformers I have left over from another project. Keep you posted.
I've been plugging Pass Korg into everything to try it out. I wired a headphone jack to the outputs because there was an extra hole up front on the chassis, or, 'because it was there'.
As is, it is not an ideal headphone amp. An ideal headphone amp should have very low output impedance and probably 50 to a hundred milliwatts at 100 ohms. A more ideal headphone amp would work well with headphones up to 600 ohms and moderate sensitivity. I gather that the JFETs are only used as buffers and do not amplify either voltage or current, so the standard form of the Pass Korg is limited to the power output of 1.7 milliwatts @ 170 ohms or so(???).
Nonetheless, I have been having a wonderful time with it listening with Sony MDR Z1R headphones, which come in at 100db/milliwatt @ 64 ohms. I suppose the impedance mismatch could have consequences on frequency response, but it sounds great this way. It's certainly as loud as I can stand out of a Yamaha receiver/dac. I can't really tell if it suffers from current starvation.
Z1R is a very expensive headphone, but the good news is Pass Korg sounds very nearly as good with the much less expensive little brother, the Sony MDR Z7 which I use at another location and has similar specs. This winds up being in H2 positive, which still sounds very good to me.
Also, using a beat up pair of old Sennheiser HD 580 97db/milliwatt @ 300 ohms sounds really good (??). The Senn has better impedance spec, but I just would not have guessed the power would be enough. I would say very, very good seductive sound, certainly better than the Yamaha's op amp headphone output. I had to turn up the gain on the Yamaha a bit with the Senn 580, but not that high, and the Korg is maybe two thirds to max. Somehow, beyond expectations, it works pretty well as a headphone amp with sensitive headphones straight out of the chute, unless I am missing something and it is picking up some power from the buffers.
I think mighty mite Pass Korg is improving with break in. I surmised it wouldn't have break in for some reason but it seems to be seasoning for the better with use.
As is, it is not an ideal headphone amp. An ideal headphone amp should have very low output impedance and probably 50 to a hundred milliwatts at 100 ohms. A more ideal headphone amp would work well with headphones up to 600 ohms and moderate sensitivity. I gather that the JFETs are only used as buffers and do not amplify either voltage or current, so the standard form of the Pass Korg is limited to the power output of 1.7 milliwatts @ 170 ohms or so(???).
Nonetheless, I have been having a wonderful time with it listening with Sony MDR Z1R headphones, which come in at 100db/milliwatt @ 64 ohms. I suppose the impedance mismatch could have consequences on frequency response, but it sounds great this way. It's certainly as loud as I can stand out of a Yamaha receiver/dac. I can't really tell if it suffers from current starvation.
Z1R is a very expensive headphone, but the good news is Pass Korg sounds very nearly as good with the much less expensive little brother, the Sony MDR Z7 which I use at another location and has similar specs. This winds up being in H2 positive, which still sounds very good to me.
Also, using a beat up pair of old Sennheiser HD 580 97db/milliwatt @ 300 ohms sounds really good (??). The Senn has better impedance spec, but I just would not have guessed the power would be enough. I would say very, very good seductive sound, certainly better than the Yamaha's op amp headphone output. I had to turn up the gain on the Yamaha a bit with the Senn 580, but not that high, and the Korg is maybe two thirds to max. Somehow, beyond expectations, it works pretty well as a headphone amp with sensitive headphones straight out of the chute, unless I am missing something and it is picking up some power from the buffers.
I think mighty mite Pass Korg is improving with break in. I surmised it wouldn't have break in for some reason but it seems to be seasoning for the better with use.
to cjfrbw #2148
Interesting test to use the B1 NUTUBE as a headphonamp.
I think I will try next few days to hang my old STAX SR5 GOLD (my acoustic microscope) behind B1 NUTUBE + M2X. It is made to hang on a poweramp.
But I have to check if I can reverse polarity? I think the STAX SRD-6 SB - adaptor for earspeakers has a transformer(s). Input is over loudspeakercable.
I am curious about the results.
Greets
Dirk
Interesting test to use the B1 NUTUBE as a headphonamp.
I think I will try next few days to hang my old STAX SR5 GOLD (my acoustic microscope) behind B1 NUTUBE + M2X. It is made to hang on a poweramp.
But I have to check if I can reverse polarity? I think the STAX SRD-6 SB - adaptor for earspeakers has a transformer(s). Input is over loudspeakercable.
I am curious about the results.
Greets
Dirk
This is exactly what I used and have done. I have no issues what so ever even with the smps just 25mm (or maybe less) from the B1 korg board. Though I did tweak the smps voltage back to 22v to enable T5&6 spec.
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Does this mean that the J113 is not good at imaging? Or did you use it differently than in the B1 triode?
Or could it be the choice of bias and inverting?
From Firstwatt Article:
When you invert the phase of the output of the Nutube to get correct phase, then you invert the phase of the second harmonic as well, and now it becomes negative phase second.
This is often what we want, but not always. Routinely people describe negative phase second harmonic distortion as having a deeper sound stage and a magnified illusion of placement of instruments in that depth. Positive phase second harmonic distortion is often described as more up close, intimate and perhaps more detailed.
From Firstwatt Article:
When you invert the phase of the output of the Nutube to get correct phase, then you invert the phase of the second harmonic as well, and now it becomes negative phase second.
This is often what we want, but not always. Routinely people describe negative phase second harmonic distortion as having a deeper sound stage and a magnified illusion of placement of instruments in that depth. Positive phase second harmonic distortion is often described as more up close, intimate and perhaps more detailed.
B1 NUTUBE experience
Hello B1 NUTUBE - builders,
today I tried an 'unusual' combination:
B1 NUTUBE + M2X as a headphoneamp.
I put my old STAX SR-5 GOLD ('working' 25 years for me) on that combo.
I tried it with normal polarity at the speakeroutput. I first have to check the
schematic of SRD-6 before I reverse polarity.
I love my old STAX - it is for me an acoustic microscope - it doesn't pardon a bad recording.
And it is fast. This is why I like elektrostatic loudspeakers (with all there pro and cons).
I expected some noise. Nothing. Not audible for me.
This showed me how good the B1 NUTUBE (and the M2X) can be.
I adjusted the 10 kOhm pots at the B1 NUTUBE. Differences were audible.
But not as much as on the normal loudspeakers with reversed polarity.
Will report more. But I am busy with other projects.
Greets
Dirk
Hello B1 NUTUBE - builders,
today I tried an 'unusual' combination:
B1 NUTUBE + M2X as a headphoneamp.
I put my old STAX SR-5 GOLD ('working' 25 years for me) on that combo.
I tried it with normal polarity at the speakeroutput. I first have to check the
schematic of SRD-6 before I reverse polarity.
I love my old STAX - it is for me an acoustic microscope - it doesn't pardon a bad recording.
And it is fast. This is why I like elektrostatic loudspeakers (with all there pro and cons).
I expected some noise. Nothing. Not audible for me.
This showed me how good the B1 NUTUBE (and the M2X) can be.
I adjusted the 10 kOhm pots at the B1 NUTUBE. Differences were audible.
But not as much as on the normal loudspeakers with reversed polarity.
Will report more. But I am busy with other projects.
Greets
Dirk
Attachments
Thanks Laverda for your feedback
Have you done an antivibration support for mounting the meanwell?
I have also tried Pass Korg with Stax rig partnered with Pass Clone VFET amp/Dyna Z565 transformer. It is my 'ultimate' headphone rig for detail, sweetness, body etc.
Pass Korg isn't 'necessary' due to Yamaha, it acts more as a buffer here, but sounds really nice again.
I can't quite understand how good it sounds with Sennheiser HD580 through headphone output, like they were made for each other. I would have predicted inadequate output, but it is huge soundstage and rich, full sound at full volume.
I bought the Senn HD 580 over twelve years ago for $120 and have roundly abused it, tossing it around in closets and such. It's pretty ratted out. Pass Korg makes it sound magical.
Pass Korg isn't 'necessary' due to Yamaha, it acts more as a buffer here, but sounds really nice again.
I can't quite understand how good it sounds with Sennheiser HD580 through headphone output, like they were made for each other. I would have predicted inadequate output, but it is huge soundstage and rich, full sound at full volume.
I bought the Senn HD 580 over twelve years ago for $120 and have roundly abused it, tossing it around in closets and such. It's pretty ratted out. Pass Korg makes it sound magical.
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Yes, I used 7mm thick double sided sticky 3M foam 50mm wide (as I had some anyway and saved me drilling) No other fixing..no good for shipping but ok for my needs from workshop to listening room.
You can just see the gap under the smps.Attachments
Looks like a SMPS.
Of course, there's Pete's Korg tube with class D hybrid:
NuClassD 50W Nutube hybrid amp
Of course, there's Pete's Korg tube with class D hybrid:
NuClassD 50W Nutube hybrid amp