Nice progress JWC, your already very close to first sound!
Excellent advice from Anand and Hugh. For all my SLB's, I adjust the trimmers for the lowest voltage possible with both rail voltages equal.
Thanks for the SemiSouth reminder Hugh.
Anand, have you any movement towards this experiment?
Best,
Vunce
Excellent advice from Anand and Hugh. For all my SLB's, I adjust the trimmers for the lowest voltage possible with both rail voltages equal.
Thanks for the SemiSouth reminder Hugh.
Anand, have you any movement towards this experiment?
Best,
Vunce
Lowest possible voltage of 28.7v across all four rails is exactly where I've landed. 22R for R113 on both boards is also where I've landed. Everything seems to be checking out great. Thanks all for your help and encouragement. I'll share results and photos when I've finished the build.Nice progress JWC, your already very close to first sound!
Excellent advice from Anand and Hugh. For all my SLB's, I adjust the trimmers for the lowest voltage possible with both rail voltages equal.
Thanks for the SemiSouth reminder Hugh.
Anand, have you any movement towards this experiment?
Best,
Vunce
I have sounds! Furthermore, they are good sounds! Currently burning it in with my iPad as a source into my old KG3.5's. No issues so far.
I still have some work to do on the case and waiting on one of the new SFP boards from XRK to replace the thermistor I'm using right now.
I still have some work to do on the case and waiting on one of the new SFP boards from XRK to replace the thermistor I'm using right now.
@JWCoffman Great looking build for a noob!
Some serious input caps there. Looking forward to your listening impressions.
Great looking build for a noob!Some serious input caps there. Looking forward to your listening impressions.
@JWCoffman
I'm curious as well, it looks like a Miflex bypass, but what is your base cap? Looks pretty big!! Appears to be SLB supplies on riser panels.
Best,
Anand.
I'm curious as well, it looks like a Miflex bypass, but what is your base cap? Looks pretty big!! Appears to be SLB supplies on riser panels.
Best,
Anand.
@twocents & @AKSA thank you for your kind words.
I should clarify that I'm a relative noob compared to many of the frequent contributors here. This is actually my fourth amp/preamp build after having built the Akitika GT-102, the VTA PH-16, and the VTA SP-14. All those previous builds were much more "paint by numbers" than this one which requires more knowledge and skill from the builder. I have zero training and experience in such things before that. I had to pore over the schematics and through this forum many times to get my head around a few items. In the end, I learned way more from this project than any of the others. It also makes it extremely satisfying to hear it sing.
@poseidonsvoice Those are Mundorf Mcap Supremes and they are huge. Anything that makes a Miflex cap look tiny has to be big. The distributor actually sent me an email before shipping them to make sure I knew their dimensions. I had two 0.1uF Miflex caps left over from another project and they made perfect sense as a bypass, so it was really just deciding what to pair them with and decided to give the MCaps a shot. You are correct that I've got two SLB boards on the panels which are serving double-duty as heat sinks.
On the sound: First, this amp is dead silent even with my ear to the tweeter, and I have no turn on or turn off thumps
. I've got about 6 hours run time in on my test setup while working on the last few items on the case. These floorstanders are rather boomy in my workspace so I can't speak to bass frequencies, but I've never heard these Klipsch's sound so good through mid-range and higher, even with the an iPad as a source. My wife described the sound as "clean" which I would agree with. I'll withhold further judgements until after I get it into my main rig and can compare it to the Akitika which has been my main amp for the past year or so. I'll be running this through my GR X-MTM's and two servo subs (also built by me). I'll be sure to given more info as I proceed.
I should clarify that I'm a relative noob compared to many of the frequent contributors here. This is actually my fourth amp/preamp build after having built the Akitika GT-102, the VTA PH-16, and the VTA SP-14. All those previous builds were much more "paint by numbers" than this one which requires more knowledge and skill from the builder. I have zero training and experience in such things before that. I had to pore over the schematics and through this forum many times to get my head around a few items. In the end, I learned way more from this project than any of the others. It also makes it extremely satisfying to hear it sing.
@poseidonsvoice Those are Mundorf Mcap Supremes and they are huge. Anything that makes a Miflex cap look tiny has to be big. The distributor actually sent me an email before shipping them to make sure I knew their dimensions. I had two 0.1uF Miflex caps left over from another project and they made perfect sense as a bypass, so it was really just deciding what to pair them with and decided to give the MCaps a shot. You are correct that I've got two SLB boards on the panels which are serving double-duty as heat sinks.
On the sound: First, this amp is dead silent even with my ear to the tweeter, and I have no turn on or turn off thumps
. I've got about 6 hours run time in on my test setup while working on the last few items on the case. These floorstanders are rather boomy in my workspace so I can't speak to bass frequencies, but I've never heard these Klipsch's sound so good through mid-range and higher, even with the an iPad as a source. My wife described the sound as "clean" which I would agree with. I'll withhold further judgements until after I get it into my main rig and can compare it to the Akitika which has been my main amp for the past year or so. I'll be running this through my GR X-MTM's and two servo subs (also built by me). I'll be sure to given more info as I proceed.
@poseidonsvoice Will do!
BTW, I believe it was a post of yours somewhere (maybe AudioCircle?) that got me curious about this amp in the first place. I was dead set on an Aleph build, but after reading your impresssions and those of others here I decided to give it a shot. Thanks for that.
BTW, I believe it was a post of yours somewhere (maybe AudioCircle?) that got me curious about this amp in the first place. I was dead set on an Aleph build, but after reading your impresssions and those of others here I decided to give it a shot. Thanks for that.
Great results, JWC!
Thank you very much for letting us your subjectives, very important since many parameters of amps tell us nothing about the sound quality.
It is a very simple amp, but quite refined, and if you love Class A, this is one of the better amps and up there with the Pass DIYers.
And it's efficient and really has good bass!
Hugh
Thank you very much for letting us your subjectives, very important since many parameters of amps tell us nothing about the sound quality.
It is a very simple amp, but quite refined, and if you love Class A, this is one of the better amps and up there with the Pass DIYers.
And it's efficient and really has good bass!
Hugh
I got it into my main rig last night and had a hard time tearing myself away to go to bed.
My setup:
Digital is DSD or Tidal from a Mac Mini via Roon through the Geshelli J2S DAC with Sparkos opamp and powered by a Sigma11 LPS > VTA SP-14 preamp with NOS Sylvania 6SN7GTB tubes > Alpha Nirvana > GR Research X-MTM's. Vinyl is via the Pioneer PL-550 with the MP110 > VTA PH-16 phono stage with NOS Sylvania 6922 tubes > SP-14 preamp. Two Rythmik subs are running off the second stereo outputs of the preamp.
As I mentioned in a previous post, my amp for the last year and a half has been the Akitika GT-102 (the 4ohm version), which I've enjoyed and was my first amp build, and that is really my only reference point for the Alpha Nirvana.
These are still very early impressions, I should spend more time with it and let it settle in before making any final judgements. I should also mention that I just added the Sparkos opamp and LPS to my DAC this past week as well, so I tried to focus most of my impressions of the amp from vinyl rather than digital. Some standout records were Joni Mitchell's Blue, Coltrane's Blue Train (one of my favorites for soundstage), Pixies Surfer Rosa (percussions are great on this one), Herbie Hancock's Headhunters.
First, the bass is no joke. This thing has punch and resolution. With the Akitika I could hear a bass string being plucked, but with the AN I hear the string move and decay with more realism. Overtones on instruments like pianos are more realistic. Percussions have slightly more precision and weight, and I think the Akitika performs well there too. Imaging is pinpoint precise and my big MTM's disappear more with the AN than the Akitika. This thing brings heft to the music, but not in an overbearing way. My wife noted that the music just feels more fleshed out and less flat, which I thought was a good way to describe it. The only downsides I perceive so far are the upper end felt a little constrained or even harsh on particularly busy passages, but I think the input caps need more time to settle in (I still have less than 10 hours on them), so I don't think that's truly indicative of it's performance. The other issue is I may need to readjust my subwoofer settings.
Long story short, I already really enjoy it and I think it will only get better. I'll have more photos to share once I've gotten everything fully done. I don't have the switch or clipping LED's wired to the front yet of the amp yet, I'm going to finish all that when I get the soft start installed.
My setup:
Digital is DSD or Tidal from a Mac Mini via Roon through the Geshelli J2S DAC with Sparkos opamp and powered by a Sigma11 LPS > VTA SP-14 preamp with NOS Sylvania 6SN7GTB tubes > Alpha Nirvana > GR Research X-MTM's. Vinyl is via the Pioneer PL-550 with the MP110 > VTA PH-16 phono stage with NOS Sylvania 6922 tubes > SP-14 preamp. Two Rythmik subs are running off the second stereo outputs of the preamp.
As I mentioned in a previous post, my amp for the last year and a half has been the Akitika GT-102 (the 4ohm version), which I've enjoyed and was my first amp build, and that is really my only reference point for the Alpha Nirvana.
These are still very early impressions, I should spend more time with it and let it settle in before making any final judgements. I should also mention that I just added the Sparkos opamp and LPS to my DAC this past week as well, so I tried to focus most of my impressions of the amp from vinyl rather than digital. Some standout records were Joni Mitchell's Blue, Coltrane's Blue Train (one of my favorites for soundstage), Pixies Surfer Rosa (percussions are great on this one), Herbie Hancock's Headhunters.
First, the bass is no joke. This thing has punch and resolution. With the Akitika I could hear a bass string being plucked, but with the AN I hear the string move and decay with more realism. Overtones on instruments like pianos are more realistic. Percussions have slightly more precision and weight, and I think the Akitika performs well there too. Imaging is pinpoint precise and my big MTM's disappear more with the AN than the Akitika. This thing brings heft to the music, but not in an overbearing way. My wife noted that the music just feels more fleshed out and less flat, which I thought was a good way to describe it. The only downsides I perceive so far are the upper end felt a little constrained or even harsh on particularly busy passages, but I think the input caps need more time to settle in (I still have less than 10 hours on them), so I don't think that's truly indicative of it's performance. The other issue is I may need to readjust my subwoofer settings.
Long story short, I already really enjoy it and I think it will only get better. I'll have more photos to share once I've gotten everything fully done. I don't have the switch or clipping LED's wired to the front yet of the amp yet, I'm going to finish all that when I get the soft start installed.
@bigaudioscotto
With 5U/300 (210 mm tall and 300mm wide) heatsinks and (2) Mosfets, this is what I recommend:
Vertically mount the MOSFETS, 1/3rd of the way from the bottom, so about 70mm from the bottom. This is the most important dimension.
Also…
Horizontally mount them 75 mm from the nearest edge.
To make it easy, just mount them 75mm X 75 mm from the bottom corners. This is assuming that the main board that holds the Alpha Nirvana doesn’t encroach upon the snubber boards. I forgot what the dimensions of the Alpha Nirvana board are, but you have that in front of you. If they are too close to the Alpha Nirvana main board just move them a little further apart, but there is leeway here depending on how you want it to look and also nearby components in your build of course.
The 5U/300 is about 0.18 degC/watt. So given the 90 watts of dissipation for the 2 Mosfets, you should see about a 16 degree C increase over ambient (25 degrees C) which is 41 or 42 degrees C. I think if you are at 45 degrees C, you are just fine. Hopefully you own an infrared thermometer or equivalent. If you don’t, no worries, with 45 degrees C you should be able to place your hand on the heatsink for a good 10 seconds.
Best,
Anand.
With 5U/300 (210 mm tall and 300mm wide) heatsinks and (2) Mosfets, this is what I recommend:
Vertically mount the MOSFETS, 1/3rd of the way from the bottom, so about 70mm from the bottom. This is the most important dimension.
Also…
Horizontally mount them 75 mm from the nearest edge.
To make it easy, just mount them 75mm X 75 mm from the bottom corners. This is assuming that the main board that holds the Alpha Nirvana doesn’t encroach upon the snubber boards. I forgot what the dimensions of the Alpha Nirvana board are, but you have that in front of you. If they are too close to the Alpha Nirvana main board just move them a little further apart, but there is leeway here depending on how you want it to look and also nearby components in your build of course.
The 5U/300 is about 0.18 degC/watt. So given the 90 watts of dissipation for the 2 Mosfets, you should see about a 16 degree C increase over ambient (25 degrees C) which is 41 or 42 degrees C. I think if you are at 45 degrees C, you are just fine. Hopefully you own an infrared thermometer or equivalent. If you don’t, no worries, with 45 degrees C you should be able to place your hand on the heatsink for a good 10 seconds.
Best,
Anand.
Hey Scott,
I used a 5U 400mm chassis, the heatsinks were a steady 50-51°C when ambient temp is 22°C.
Keep an eye on your temps with 5U 300mm sinks.
Edit: built with +/-28V rails.
https://www.diyaudio.com/community/attachments/13b29f9e-b505-4932-93fc-b35d2d01b3f0-jpg.817239/
I used a 5U 400mm chassis, the heatsinks were a steady 50-51°C when ambient temp is 22°C.
Keep an eye on your temps with 5U 300mm sinks.
Edit: built with +/-28V rails.
https://www.diyaudio.com/community/attachments/13b29f9e-b505-4932-93fc-b35d2d01b3f0-jpg.817239/
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