Hi, with a little late, here are some pics of the B1 with Korg Triode . This is the Christmas version. I used an economic Hi-Fi2000 chassis.
T7-T8 = 9.5V
2H+ with 1V/1KHz at output, THD = 1.41%. To notice the 3nd harmonic as much as 24dB below the 2nd.
2H+ with 0.44V/1KHz at output, THD = 0.53% to have 1WATT with a Sony VFET Amplifier part 2.
Thank you Mr. Pass for this wonderful project.
T7-T8 = 9.5V
2H+ with 1V/1KHz at output, THD = 1.41%. To notice the 3nd harmonic as much as 24dB below the 2nd.
2H+ with 0.44V/1KHz at output, THD = 0.53% to have 1WATT with a Sony VFET Amplifier part 2.
Thank you Mr. Pass for this wonderful project.
Attachments
Today I had the pleasure of attending my local HiFi Groups Meeting and was able to supply a input to the evaluations of three build versions of the Korg B1.
Within the Group there are four members going down the Korg B1 build route.
Myself and one member are having a 'yet to be completed' build produced.
One member has produced their first build, which is one and two in the
lineup.
One member has built two models and a purpose built power supply, which will be two, three and four in the lineup.
Firstly was a Partially Complete (Open Casing) recently built model, which was walwart powered, with a Dual Channel Selector and Dual Volume Control declared as being set at 11.5V.
This was a great opening and showed the Lucidity that the Korg B1 has in great measure.
This model was then used for the second in the lineup and attached to a Standalone Power Supply that has been purposely produced for the Korg B1.
I feel it is fair to call this a two box design.
With the new Power Supply there was a noticeable change in the presentation, there was a noticeable forward projection and extra weight to the performers, that to my perception gave the impression of much more authority and control, with no loss to any of the valued sonic traits that the Korg B1 delivers.
Third in the lineup was a Three Box Design.
Box 1, a Promitheus TVC as the Volume Control and Channel Selector.
Box 2, a basic build Korg B1 with inputs and output RCA's only.
Box 3, the previous used Standalone Power Supply.
This was very interesting as it was slightly different in its presentation than the already impressive previous model.
It got more debate about its Sound Quality than the previous two models.
I have a Slagle AVC and felt I could pick up on a signature of an AVC in the overall SQ.
What was different that the previous models was the forcefulness of the prominent parts of a recording, they were projected forward with a energy.
The Bass from my perception was more extended with any extra weight that seemed to rein in the earlier perceptions of a accentuated Mid and High frequency.
After a few tracks I come to the conclusion the additional Bass, was just not allowing the accentuated Mid and Highs their freedom to be noticed, but the Mid and Highs were achieving almost identical limits as the previous models allowed.
There was to my perception a slight masking of the Lucidity that is available, and for me this was becoming a detractor, as I was noticing this element of loss to the SQ.
I was off the impression the second model in the lineup was my choice of presentation.
Fourth in the lineup was a Slightly different concept on the assembly to the previous model.
A Three Box Design, produced by the builder of the
'Purpose Built Power Supply' and the 'Box 2 from the Third in the lineup'.
Box 1, Dual Mono Tocos Logarithmic Pot's
Box 2, PCB and Dual Channel Selectors, with a muting adaption.
This PCB has Boutique Cap's, Blackgates were mentioned, as well as high spec' resistors.
Box 3,Previously used Purpose Built Power Supply.
This was put on without a warm up, and immediately it was very impressive.
The Pot's proved to be very controlled in the adjusting the volume across the channels and to me were a desirable method,adding to the good impression already in place, but that might be my Dual Mono Slagle AVC experience taking over.
More importantly, this build had measurably surpassed all others in the lineup at delivering a performance that I have come to understand that a Korg B1 can offer.
It was the most Lucid without drawing attention to the quality of this trait.
The Sound Stage was wide, with a depth that did not seem to have a horizon.
The Performance projected out in front of the speakers, with a clearly defined centre image and the very perceivable sense of space around the performers.
The instruments in use sounded more than usual real, leaving a strong perception that there was a honesty in the sounds being heard.
The Bass, Mid's and Highs, did not feel in any way out of harmony.
The overall experience was ethereal, not so common at least.
All attendees had voiced their liking for this model, and for the extra £150 required to excel to this level it was a 'no brainer' as to where the group members builds will eventually end up.
All the above were carried out with CD as the source.
The Fourth in the lineup was used with the Vinyl Set Up that was put in service after a recess period for lunch.
The Korg B1 used with Vinyl was totally to my taste and this model is at the top of my list as my goal for my build.
My search for a alternative pre amp, and my stumbling on the Korg B1 thread has been a great journey of discovery.
Since my learning of the ever growing thread and interest, I have encouraged a few to have a look in.
One of those individuals has a great understanding of such projects, and took on the build.
The impression it made has led onto others hearing the build buy into it and produce their own, as well create a stimulus that has produced the various build guises witnessed today.
I feel fortunate to have been able to witness the valued impression the
Korg B1 is generating, and at a cost that is so affordable, even in a boutique component form.
Within the Group there are four members going down the Korg B1 build route.
Myself and one member are having a 'yet to be completed' build produced.
One member has produced their first build, which is one and two in the
lineup.
One member has built two models and a purpose built power supply, which will be two, three and four in the lineup.
Firstly was a Partially Complete (Open Casing) recently built model, which was walwart powered, with a Dual Channel Selector and Dual Volume Control declared as being set at 11.5V.
This was a great opening and showed the Lucidity that the Korg B1 has in great measure.
This model was then used for the second in the lineup and attached to a Standalone Power Supply that has been purposely produced for the Korg B1.
I feel it is fair to call this a two box design.
With the new Power Supply there was a noticeable change in the presentation, there was a noticeable forward projection and extra weight to the performers, that to my perception gave the impression of much more authority and control, with no loss to any of the valued sonic traits that the Korg B1 delivers.
Third in the lineup was a Three Box Design.
Box 1, a Promitheus TVC as the Volume Control and Channel Selector.
Box 2, a basic build Korg B1 with inputs and output RCA's only.
Box 3, the previous used Standalone Power Supply.
This was very interesting as it was slightly different in its presentation than the already impressive previous model.
It got more debate about its Sound Quality than the previous two models.
I have a Slagle AVC and felt I could pick up on a signature of an AVC in the overall SQ.
What was different that the previous models was the forcefulness of the prominent parts of a recording, they were projected forward with a energy.
The Bass from my perception was more extended with any extra weight that seemed to rein in the earlier perceptions of a accentuated Mid and High frequency.
After a few tracks I come to the conclusion the additional Bass, was just not allowing the accentuated Mid and Highs their freedom to be noticed, but the Mid and Highs were achieving almost identical limits as the previous models allowed.
There was to my perception a slight masking of the Lucidity that is available, and for me this was becoming a detractor, as I was noticing this element of loss to the SQ.
I was off the impression the second model in the lineup was my choice of presentation.
Fourth in the lineup was a Slightly different concept on the assembly to the previous model.
A Three Box Design, produced by the builder of the
'Purpose Built Power Supply' and the 'Box 2 from the Third in the lineup'.
Box 1, Dual Mono Tocos Logarithmic Pot's
Box 2, PCB and Dual Channel Selectors, with a muting adaption.
This PCB has Boutique Cap's, Blackgates were mentioned, as well as high spec' resistors.
Box 3,Previously used Purpose Built Power Supply.
This was put on without a warm up, and immediately it was very impressive.
The Pot's proved to be very controlled in the adjusting the volume across the channels and to me were a desirable method,adding to the good impression already in place, but that might be my Dual Mono Slagle AVC experience taking over.
More importantly, this build had measurably surpassed all others in the lineup at delivering a performance that I have come to understand that a Korg B1 can offer.
It was the most Lucid without drawing attention to the quality of this trait.
The Sound Stage was wide, with a depth that did not seem to have a horizon.
The Performance projected out in front of the speakers, with a clearly defined centre image and the very perceivable sense of space around the performers.
The instruments in use sounded more than usual real, leaving a strong perception that there was a honesty in the sounds being heard.
The Bass, Mid's and Highs, did not feel in any way out of harmony.
The overall experience was ethereal, not so common at least.
All attendees had voiced their liking for this model, and for the extra £150 required to excel to this level it was a 'no brainer' as to where the group members builds will eventually end up.
All the above were carried out with CD as the source.
The Fourth in the lineup was used with the Vinyl Set Up that was put in service after a recess period for lunch.
The Korg B1 used with Vinyl was totally to my taste and this model is at the top of my list as my goal for my build.
My search for a alternative pre amp, and my stumbling on the Korg B1 thread has been a great journey of discovery.
Since my learning of the ever growing thread and interest, I have encouraged a few to have a look in.
One of those individuals has a great understanding of such projects, and took on the build.
The impression it made has led onto others hearing the build buy into it and produce their own, as well create a stimulus that has produced the various build guises witnessed today.
I feel fortunate to have been able to witness the valued impression the
Korg B1 is generating, and at a cost that is so affordable, even in a boutique component form.
Thanks for a very informative write up.
Bottom line is that better caps and PS did make a difference.
Although I have not tried it yet, and as a Slagle AVC builder myself, a shunt powered buffer preceding the AVC and then followed by the B1 Korg might just prove the best to your ears.
Something like ZM's Iron Pre which I hope the diyaudiostore will start selling soon.
nash
Bottom line is that better caps and PS did make a difference.
Although I have not tried it yet, and as a Slagle AVC builder myself, a shunt powered buffer preceding the AVC and then followed by the B1 Korg might just prove the best to your ears.
Something like ZM's Iron Pre which I hope the diyaudiostore will start selling soon.
nash
The mentor to the builder of the first model in the lineup,
and the builder of the power supply and the Korg B1's used at third and fourth in the lineup has expressed much appreciation for the opportunity that the Korg B1 produced.
There was talk of how much the Korg B1 had changed the outlook of the group as prior to the group having the Korg B1 experience,
a few very expensive Pre's were on the shortlist of members within the group, these were selected from similar days of auditions, so the performances of the models was known.
These previously selected Pre's, are no longer in the running,
and when the group members original owned Pre's are sold on by their owners, there will be spare monies available once the Korg B1 monies are reimbursed
When the Korg B1 mentor/builder was congratulated on his works, he was quick to inform, that all was a result of NP's works being made available, and in making such contributions as he does to the Global HiFi community, that NP is most deserved of the congratulation.
I myself am more than happy to embrace that sentiment.
and the builder of the power supply and the Korg B1's used at third and fourth in the lineup has expressed much appreciation for the opportunity that the Korg B1 produced.
There was talk of how much the Korg B1 had changed the outlook of the group as prior to the group having the Korg B1 experience,
a few very expensive Pre's were on the shortlist of members within the group, these were selected from similar days of auditions, so the performances of the models was known.
These previously selected Pre's, are no longer in the running,
and when the group members original owned Pre's are sold on by their owners, there will be spare monies available once the Korg B1 monies are reimbursed
When the Korg B1 mentor/builder was congratulated on his works, he was quick to inform, that all was a result of NP's works being made available, and in making such contributions as he does to the Global HiFi community, that NP is most deserved of the congratulation.
I myself am more than happy to embrace that sentiment.
Last edited:
Hi JohnoG,
Thanks a lot for your detailled report!
Just to understand what you did...
My understanding is that only the 1st set up can be compared to the second, and the third to the 4th as the B1 Korg wasn't the same unit otherwise (between 2 and 3) and possibly (?) the voltage bias might not have been the same. You mentioned initialy 11.5V but then not sure about the other unit, while this pre is very tuning sensitive, so it would be worthwhile to have perhaps more precision on the tuning?
Regarding 1st vs 2nd, could you be more specific on what you used in the 1st set up as PS? My experience is that a decent wall wat SMPS with some additional PS capacity does the job very well, but that's admittely starting with a very low ripple SMPS and more than doubling the caps. The caps brought though only a slight improvement and a test with a regulated lab supply brought a slight different presentation, but more taste and coulours IMHO at the end and I stuck to my (admittely) low ripple SMPS . Hence me curious about what you compared and had as 1st set up PS (and possibly caps), as perhaps the step to the 2nd set up wasn't that big and could have been achieved otherwise?
Regarding 3rd vs 4th set up, my understanding is that the Tocos and upgraded caps seem to be the deciding factor and indeed I would second that myself - nice pot, VG VFM.
Is my reading correct?
Many thanks again and sorry for my curiosity
Claude
Thanks a lot for your detailled report!
Just to understand what you did...
My understanding is that only the 1st set up can be compared to the second, and the third to the 4th as the B1 Korg wasn't the same unit otherwise (between 2 and 3) and possibly (?) the voltage bias might not have been the same. You mentioned initialy 11.5V but then not sure about the other unit, while this pre is very tuning sensitive, so it would be worthwhile to have perhaps more precision on the tuning?
Regarding 1st vs 2nd, could you be more specific on what you used in the 1st set up as PS? My experience is that a decent wall wat SMPS with some additional PS capacity does the job very well, but that's admittely starting with a very low ripple SMPS and more than doubling the caps. The caps brought though only a slight improvement and a test with a regulated lab supply brought a slight different presentation, but more taste and coulours IMHO at the end and I stuck to my (admittely) low ripple SMPS . Hence me curious about what you compared and had as 1st set up PS (and possibly caps), as perhaps the step to the 2nd set up wasn't that big and could have been achieved otherwise?
Regarding 3rd vs 4th set up, my understanding is that the Tocos and upgraded caps seem to be the deciding factor and indeed I would second that myself - nice pot, VG VFM.
Is my reading correct?
Many thanks again and sorry for my curiosity
Claude
Last edited:
I will repeat, my contribution to Korg's original circuit was marginal.
I mostly helped to make the design more accessible.
Thank You for the interest in the outcome of the comparisons of the Korg B1 Build.
This is where I let the side down, as I am not EE minded, so I am trying to pass on the descriptions given on the day.
To get the info available to make clear what was the differences between each assembly,
I will have to ask the Korg B1 owners to contribute.
The Walwart PS was only used once on the First in the line up, which was a Basic Built Korg B1, with a inbuilt dual mono volume control and inbuilt dual channel selection, which I believe will be classed as a one box build, even though the Power Supply was a Laptop Type off board plug in.
The second audition in the line up was the same Basic Built Korg B1, as used in the first audition, but with the exchange of a PS, as indicated below, I referred to this as a two box build.
The auditions that were carried out in the line up at positions,
Two, Three and Four were powered with the Purpose Built PS.
The third in the line up was a standard built Korg B1 PCB, with a Input/Output RCA and a umbilical power cable.
The Volume Control and Channel Selection was supplied by a Promitheus TVC.
This assembly made it a unique version of a Korg B1 on the day.
This will be the type of arrangement I will be going for as my first model, substituting the TVC for my Slagle Dual Mono AVC.
Another member yesterday referenced a Shunt Powered Buffer Precedeing the AVC as another configuration.
Can a description be supplied as to how this will function in the assembly ?
As a variant for a later version, and for R&D purposes, I was pondering having a Dual Mono Muse Volume Control produced, if there is such a thing ?
The fourth in the line up, was another unique assembly, as the TOCOS were in there own box, the Dual Channel Selectors, Korg B1 PCB with Blackgate's and a muting design, was in its own box.
I have requested the Voltages for the Korg B1 used in line up Three and Four.
There is a lot to be achieved from the Korg B1, as was revealed at these comparisons.
The basic model is a great starting place, and will be more than sufficient for many who build.
I had the basic model in my system recently and compared it to my AVC, and it was very impressive.
This is where I let the side down, as I am not EE minded, so I am trying to pass on the descriptions given on the day.
To get the info available to make clear what was the differences between each assembly,
I will have to ask the Korg B1 owners to contribute.
The Walwart PS was only used once on the First in the line up, which was a Basic Built Korg B1, with a inbuilt dual mono volume control and inbuilt dual channel selection, which I believe will be classed as a one box build, even though the Power Supply was a Laptop Type off board plug in.
The second audition in the line up was the same Basic Built Korg B1, as used in the first audition, but with the exchange of a PS, as indicated below, I referred to this as a two box build.
The auditions that were carried out in the line up at positions,
Two, Three and Four were powered with the Purpose Built PS.
The third in the line up was a standard built Korg B1 PCB, with a Input/Output RCA and a umbilical power cable.
The Volume Control and Channel Selection was supplied by a Promitheus TVC.
This assembly made it a unique version of a Korg B1 on the day.
This will be the type of arrangement I will be going for as my first model, substituting the TVC for my Slagle Dual Mono AVC.
Another member yesterday referenced a Shunt Powered Buffer Precedeing the AVC as another configuration.
Can a description be supplied as to how this will function in the assembly ?
As a variant for a later version, and for R&D purposes, I was pondering having a Dual Mono Muse Volume Control produced, if there is such a thing ?
The fourth in the line up, was another unique assembly, as the TOCOS were in there own box, the Dual Channel Selectors, Korg B1 PCB with Blackgate's and a muting design, was in its own box.
I have requested the Voltages for the Korg B1 used in line up Three and Four.
There is a lot to be achieved from the Korg B1, as was revealed at these comparisons.
The basic model is a great starting place, and will be more than sufficient for many who build.
I had the basic model in my system recently and compared it to my AVC, and it was very impressive.
Thanks JohnnoG!
I suspect the 2nd option only had a slight edge because the laptop SMPS and the existing PS caps on the board may not have been optimised (eg low ripple wall wart + doubling the capacitance)... but sadly we won't know. It is a shame so many people try different PS but apparently without starting from what Papa recommended as a baseline. I too didn't think a simple SMPS could do it and had several B plans as I expected an easy bottleneck there, but as I found out I was wrong. All to my ears of course...
Comparing the Muse volume control with the Tocos would be absolutely great. Eventhough the Tocos was close to my absolute reference, there is still a little something to be gained in the bass especialy and as Papa uses the MUSE it would be great to see how closer it gets to perfection.
Sadly, simple MUSE volume control kits (without anything else) aren't apprently DIY, there is company in the US that sells a populated board but it is 70$.
Keep us posted if you manage to compare MUSE vs Tocos, a shoutout I am eager to read
Claude
I suspect the 2nd option only had a slight edge because the laptop SMPS and the existing PS caps on the board may not have been optimised (eg low ripple wall wart + doubling the capacitance)... but sadly we won't know. It is a shame so many people try different PS but apparently without starting from what Papa recommended as a baseline. I too didn't think a simple SMPS could do it and had several B plans as I expected an easy bottleneck there, but as I found out I was wrong. All to my ears of course...
Comparing the Muse volume control with the Tocos would be absolutely great. Eventhough the Tocos was close to my absolute reference, there is still a little something to be gained in the bass especialy and as Papa uses the MUSE it would be great to see how closer it gets to perfection.
Sadly, simple MUSE volume control kits (without anything else) aren't apprently DIY, there is company in the US that sells a populated board but it is 70$.
Keep us posted if you manage to compare MUSE vs Tocos, a shoutout I am eager to read
Claude
There isn’t a “concise” build guide but post 1803 and the following few posts have have some good info.
B1 with Korg Triode