Borg k1 review
This may be a bit long but hopefully helpful. Context-I think I have written less than 5 comments in any venue (Amazon, etc) ever so fact I’m doing this at all should lend significance to these observations. More context - I have been in hobby for about 34 years and have owned lots of top notch equipment : lamm, audio research, krell, counterpoint, transcendent, Martin Logan, acoustat, audiostatic, Proac ( lol, autocorrect wanted to change this to Prozac), Meitner, kef, harbeth, you name it. I currently own and use ram labs rm9ii, Bryson 4bst, pass diy f6, ba3 pre, aleph3 diy (original version). I did own f3 and aleph j, so have familiarity there. Now the punchline. The borg pre is world class performance. I thought ba3 pre was good, but this thing sounds better than anything I have owned previously. It has transformed my system into something so holographic and organic as to sound real on great recordings and makes poor recordings very listenable, even good. This is pairing it with f6 which is magical. Repeat magical. It sounded impressive with aleph 3, and other amps but truly transformed when paired with f6. For the first time ever I don’t have an itch to change anything. Every diyer should do themselves favor and build it. I used everything stock from white paper bom but used twisted pear power supply (positive leg only) and Anker 22v trans. Also used dueland wire. I believe wire makes a difference and I can hear it - whether it is due to metallurgy, dielectric, layout, L/C/R relationship, dunno and no one else does but it makes a difference. This does not mean I condone the wire industry in fact when $8k 8ft wire first started coming on scene years ago , I was so disgusted I left the hobby for awhile. That’s not to say $8k wire can’t sound outstanding, but there is absolutely no value there, even if I were a multi millionaire. Rest of system is rega mid level tt, chord dac with computer server, mogami ic’s (great reasonable wire) and synergistic speaker wire (kimber 8tc works well too and sound very good). Speakers are Solstice by Jeff bagby from parts express. Do yourself a favor there too. Build these. They are incredible and sound better than anything I have heard or owned less than $10k. No exaggeration. They are full range, incredibly dynamic, perfect top end, airy and open, transparent, detailed, and holographic imaging. Solidity and roundness to images in space. Midrange to die for. Again, have absolutely no desire to change unless I came into large sum of money and would then get Wilson Sasha. My borg I have set to about 10.5v. Had it at 9.5 but it sounded a bit dark and muddled, then read white paper again and saw Nelson’s comment that it is not necessarily the ideal point. If 11.5v is approximate null, and each .1v increment translates to about .1% distortion, I figured 10.5 would get me to the target of 1% at 1v. I was going to check everything with ARTA to make sure everything is balanced and right, but it has sounded so damn good that I don’t feel a need. I think a good linear supply is better. Did not try the wallwart/brick method, but it can only be more edgy in my mind, and for those who thought it sounded better this way, i think you can accomplish same thing by adjusting pots if you need a bit more “sharpness” to sound. Anyway, hope this is helpful. Thank you Nelson for sharing your genius. Whenever I now go to listen to my system, I am spellbound (and probably have a stupid grin too). Best sound I have ever had at home.
This may be a bit long but hopefully helpful. Context-I think I have written less than 5 comments in any venue (Amazon, etc) ever so fact I’m doing this at all should lend significance to these observations. More context - I have been in hobby for about 34 years and have owned lots of top notch equipment : lamm, audio research, krell, counterpoint, transcendent, Martin Logan, acoustat, audiostatic, Proac ( lol, autocorrect wanted to change this to Prozac), Meitner, kef, harbeth, you name it. I currently own and use ram labs rm9ii, Bryson 4bst, pass diy f6, ba3 pre, aleph3 diy (original version). I did own f3 and aleph j, so have familiarity there. Now the punchline. The borg pre is world class performance. I thought ba3 pre was good, but this thing sounds better than anything I have owned previously. It has transformed my system into something so holographic and organic as to sound real on great recordings and makes poor recordings very listenable, even good. This is pairing it with f6 which is magical. Repeat magical. It sounded impressive with aleph 3, and other amps but truly transformed when paired with f6. For the first time ever I don’t have an itch to change anything. Every diyer should do themselves favor and build it. I used everything stock from white paper bom but used twisted pear power supply (positive leg only) and Anker 22v trans. Also used dueland wire. I believe wire makes a difference and I can hear it - whether it is due to metallurgy, dielectric, layout, L/C/R relationship, dunno and no one else does but it makes a difference. This does not mean I condone the wire industry in fact when $8k 8ft wire first started coming on scene years ago , I was so disgusted I left the hobby for awhile. That’s not to say $8k wire can’t sound outstanding, but there is absolutely no value there, even if I were a multi millionaire. Rest of system is rega mid level tt, chord dac with computer server, mogami ic’s (great reasonable wire) and synergistic speaker wire (kimber 8tc works well too and sound very good). Speakers are Solstice by Jeff bagby from parts express. Do yourself a favor there too. Build these. They are incredible and sound better than anything I have heard or owned less than $10k. No exaggeration. They are full range, incredibly dynamic, perfect top end, airy and open, transparent, detailed, and holographic imaging. Solidity and roundness to images in space. Midrange to die for. Again, have absolutely no desire to change unless I came into large sum of money and would then get Wilson Sasha. My borg I have set to about 10.5v. Had it at 9.5 but it sounded a bit dark and muddled, then read white paper again and saw Nelson’s comment that it is not necessarily the ideal point. If 11.5v is approximate null, and each .1v increment translates to about .1% distortion, I figured 10.5 would get me to the target of 1% at 1v. I was going to check everything with ARTA to make sure everything is balanced and right, but it has sounded so damn good that I don’t feel a need. I think a good linear supply is better. Did not try the wallwart/brick method, but it can only be more edgy in my mind, and for those who thought it sounded better this way, i think you can accomplish same thing by adjusting pots if you need a bit more “sharpness” to sound. Anyway, hope this is helpful. Thank you Nelson for sharing your genius. Whenever I now go to listen to my system, I am spellbound (and probably have a stupid grin too). Best sound I have ever had at home.
I agree. I also have a B1 Korg (Papa's Xmas Special) with a DIY F6 and have not heard anything better. Have tried it with my M2X and various input modules and there is no comparison. B1K/F6 is the winning combo. Running 9.7 V on the NuTube plates. Listened at around 10.2 V for a while but went back to more H2. Running a fairly high bias of 1.25 A on the F6, which makes a difference. Needed to change the zeners to 5.6 V to get there. Output devices are at around 65 deg C.
I have some stuffed and tested Korg boards sitting here and also a bunch of H2's.
Since it's getting crowded in my space, I plan to being them to BAF.
Since it's getting crowded in my space, I plan to being them to BAF.
Send us pictures! Please🙂 I am almost done with my B1 Korg Nutube assembly. Was thinking to replace stock wires with silver wires. I used everyhthing else was in the Pioneer's kit. Which capacitors and wire did you use? FYI This is my first DIY experience: amazing what people can do to have Maestro's creations...
I realize there is 24v coming in... Could I power with battery instead or not enough juice to get tube going?
Battery is 100 AH battery I use for other amps and pre s..
JP
Battery is 100 AH battery I use for other amps and pre s..
JP
You can use a battery...the only thing is that the distortion profile is based on 24V rails. So if you deviate from a steady 24V when the battery drains the distortion profile will change.
Ok, The battery is set to trickle charge every night or when it drops below half. Will the distortion profile be "better" or worse when using at full charge?
JP
JP
I am sure "full charge" is probably over 24V. There is probably no way to tell the charger to stop charging at 24V. I bet your batteries will measure 26V-ish when fully charged.
Distortion profile will not be be better or worse but it will be different from what Mr. Pass designed if the rails are not 24V. The distortion profile changes with changes in rail voltage and unless you have someway of measuring the distortion you will not be able to get the specified harmonics at rail voltages other than 24V.
Also, max voltage for jets is 25V.
Distortion profile will not be be better or worse but it will be different from what Mr. Pass designed if the rails are not 24V. The distortion profile changes with changes in rail voltage and unless you have someway of measuring the distortion you will not be able to get the specified harmonics at rail voltages other than 24V.
Also, max voltage for jets is 25V.
12V? Not without significant rework of the circuit.
Just use a cheap SMPS wall wart at 24V. It will cost you a few dollars on amazon/ebay, etc.
Just use a cheap SMPS wall wart at 24V. It will cost you a few dollars on amazon/ebay, etc.
Never seen an answer I understood in the battery V's power supply question when posed by relative newcomers such as my self. Certainly you could by or build lithium ion batteries capable of supplying more than enough current for the same price as many mains filters and power supplies and it would be free from any of that.
Would you need any regulation of power coming from a battery or pair of?
Would you need any regulation of power coming from a battery or pair of?
Two lead acid batteries in series is 24v. Regulation not required. Would probably work very very well. Be exceedingly careful with batteries as a short can make for hundreds of amps flowing instantly. Aside that obvious warning, give it a try!
So after reading this I pulled out the F4 and poked in the F6 mosfet version, as one channel of my semi-south F6 went to audio heaven and they were curve matched
. You are right this is a very good sounding match. Kudos!!!
I still only have 1 channel working, checked just about everything, thinking it may be the Korg.
Batty, are you able to post some photos of the board top and bottom?
What steps have you taken so far to measure the board? (DVM / Oscilloscope?)
What steps have you taken so far to measure the board? (DVM / Oscilloscope?)
I'll take pics after work, all looks fine.
I have been comparing left and right channels with a DMM.
I'll have to learn how to use my USB Bitscope, it has sig gen and cro built in.
I have been comparing left and right channels with a DMM.
I'll have to learn how to use my USB Bitscope, it has sig gen and cro built in.