Hugh,
I really like my Starkrimson GaN amp, it’s one of the best sounding Class D amps I have heard.
That being said, there are marked differences with the AN.
The AN has a more “capturing” upper midrange and is able to portray the height of a 3D soundstage better than the Starkrimson (this is the 1st amp that has done this!). The Starkrimson is more neutral in that regard without calling attention to those areas but still highly detailed. The Starkrimson is better able to handle lower impedance loads and has more “impact“ in the bass, especially with large scale orchestral music (the comparison isn’t exactly fair…my Starkrimson can put out 125W/8 ohms while my AN clips at 30W due to +/-24V rails). The bass on the AN is somewhat dependent on the load. With speakers that are 5 ohms or above (since my AN build is the 8 ohm version), it is actually quite good. In my particular setup, since I have a distributed multi bass system (4 subs), I can easily tweak the overall bass spl (<200Hz) for the 2ch amplifiers that are less impactful (I have done this with the Aleph J, Aleph J Zen and ALPHA 20, all to good effect). The delineation of the bass (i.e. bass detail) is actually quite good on the AN. That delineation is less apparent when the amp is paired with speakers that are full range and have lower impedance loads (<5 ohms). That’s completely understandable of course.
I have a few colleagues who have listened to my AN and they are all in a rapture with regards to the midrange, treble and sound staging capabilities of this amplifier.
My best advice is for folks to go ahead and build the AN but build the right one (8 ohm or 4 ohm) for maximum speaker compatibility. The damping factor on the AN is quite high for an SE design so the bass doesn’t sound like a typical SE design at all. It’s actually quite tight and detailed. It is only after comparing was I aware of the bass differences. Contrast that with how I was immediately made aware of the midrange, treble and staging differences even before any comparisons were made.
Nevertheless it’s a winner. I am more than curious about substituting the N channel MOSFET with an N channel JFET in the near future.
I consider this amp as one of the best SE Class A amps I have heard. Thanks for sharing Hugh.
Best,
Anand.
I really like my Starkrimson GaN amp, it’s one of the best sounding Class D amps I have heard.
That being said, there are marked differences with the AN.
The AN has a more “capturing” upper midrange and is able to portray the height of a 3D soundstage better than the Starkrimson (this is the 1st amp that has done this!). The Starkrimson is more neutral in that regard without calling attention to those areas but still highly detailed. The Starkrimson is better able to handle lower impedance loads and has more “impact“ in the bass, especially with large scale orchestral music (the comparison isn’t exactly fair…my Starkrimson can put out 125W/8 ohms while my AN clips at 30W due to +/-24V rails). The bass on the AN is somewhat dependent on the load. With speakers that are 5 ohms or above (since my AN build is the 8 ohm version), it is actually quite good. In my particular setup, since I have a distributed multi bass system (4 subs), I can easily tweak the overall bass spl (<200Hz) for the 2ch amplifiers that are less impactful (I have done this with the Aleph J, Aleph J Zen and ALPHA 20, all to good effect). The delineation of the bass (i.e. bass detail) is actually quite good on the AN. That delineation is less apparent when the amp is paired with speakers that are full range and have lower impedance loads (<5 ohms). That’s completely understandable of course.
I have a few colleagues who have listened to my AN and they are all in a rapture with regards to the midrange, treble and sound staging capabilities of this amplifier.
My best advice is for folks to go ahead and build the AN but build the right one (8 ohm or 4 ohm) for maximum speaker compatibility. The damping factor on the AN is quite high for an SE design so the bass doesn’t sound like a typical SE design at all. It’s actually quite tight and detailed. It is only after comparing was I aware of the bass differences. Contrast that with how I was immediately made aware of the midrange, treble and staging differences even before any comparisons were made.
Nevertheless it’s a winner. I am more than curious about substituting the N channel MOSFET with an N channel JFET in the near future.
I consider this amp as one of the best SE Class A amps I have heard. Thanks for sharing Hugh.
Best,
Anand.
Thank you Anand - to hear such a glowing testimony from someone so accustomed with many good amps is wonderful to hear, and confirms I'm on the right track..... maybe in thirty years, when I'm 100 years old, I will hit the holy grail!! We all live in hope.....
I too was impressed with the Starkrimson GaN specs, more particularly, the monotonic profile from a dominant H2. Not that H2 is high; about -120dB IIRC. I see Topping is building one too, the PA5, quite cheap at about $USD345. And VTV is doing one with a tube out front; that too would be a good listen, the tube might cover any deficiencies of really good Class D.
The big issues for the AN are the limited bass power and the high output device dissipation, not to mention the cost of pouring so much electricity into the power supply! Active cooling is efficient, but I prefer to use a very large heatsink per channel, 350mmx150mm. You might try reconnecting the negative electrode of the upper bootstrap capacitor to the nmos source, Rallyfinnen tells me it improves the bass power and impact, worth a try.
Great post, thank you so much,
Hugh
I too was impressed with the Starkrimson GaN specs, more particularly, the monotonic profile from a dominant H2. Not that H2 is high; about -120dB IIRC. I see Topping is building one too, the PA5, quite cheap at about $USD345. And VTV is doing one with a tube out front; that too would be a good listen, the tube might cover any deficiencies of really good Class D.
The big issues for the AN are the limited bass power and the high output device dissipation, not to mention the cost of pouring so much electricity into the power supply! Active cooling is efficient, but I prefer to use a very large heatsink per channel, 350mmx150mm. You might try reconnecting the negative electrode of the upper bootstrap capacitor to the nmos source, Rallyfinnen tells me it improves the bass power and impact, worth a try.
Great post, thank you so much,
Hugh
I participated in listening to Anands Alpha Nirvana and Starkrimson amps at a fellow audiophiles home. I can attest the AN amp has some very captivating and lucid midrange and treble even being used with large Legacy speakers which are not ideal for a low wattage Class A amp. Also the build quality and attention to detail of Anands amps is second to none. I am looking forward to hearing the AN at my home sometime later this month to give my final judgement.
My opinions of the Starkrimson is less glowing of praise. I think compared to a Purifi based amp it is more congested and dark sounding. Everything here is purely subjective but I preferred the openness and dynamics of the Purifi over the Starkrimson.
My opinions of the Starkrimson is less glowing of praise. I think compared to a Purifi based amp it is more congested and dark sounding. Everything here is purely subjective but I preferred the openness and dynamics of the Purifi over the Starkrimson.
Hello AN39 Club:
I recently completed my build of the AN39 and thought I would share some of the details. I consider myself very lucky to have had a weekend audition of Anand's AN39 build in my system before starting the project. After hearing first hand the wonderful musical qualities that several have spoken of, it was an easy decision to undertake the build, and to ensure that I built what I heard, I followed Anand's "blueprint" pretty much as he presented earlier in this thread. Here is a list of the items that I did change in my build:
1. 4U-400 Modushop chassis versus 5U-400. Rack was not high enough for 5U.
2. 800VA Toroidy with 24V secondaries versus 20V. I was shooting for 28V rails, but with the highly efficient Toroidy and SLB supplies, I ended up with about 30V rails. Plenty of reserve, and I have yet to clip the amplifier driving it extremely hard.
3. I used Tom Christiansen's Universal Buffer (unity gain) and Preamp Power Supply to perform balanced to single ended conversion. Very nice pair that I have used previously in my preamp.
4. Miflex KPCU-03 versus VH Audio V-Cap CuTF to bypass V-Cap ODAM input caps
5. Audionote Kasei versus Nichicon Z for C111 bypass cap for the input LTP stage
Misc: Neotech UP-OCC stranded wire (22 thru 14 awg) throughout
LTP bias adjustment resulted in 2.7 mA per channel, with R/L DC offsets of 3.4 and 8.0 mV respectively. Heatsink temperature at base of Mosfets is running about 50 to 55 deg C. I am really enjoying this amplifier during the short time I have had it in my system. Definitely a keeper.
Steve
I recently completed my build of the AN39 and thought I would share some of the details. I consider myself very lucky to have had a weekend audition of Anand's AN39 build in my system before starting the project. After hearing first hand the wonderful musical qualities that several have spoken of, it was an easy decision to undertake the build, and to ensure that I built what I heard, I followed Anand's "blueprint" pretty much as he presented earlier in this thread. Here is a list of the items that I did change in my build:
1. 4U-400 Modushop chassis versus 5U-400. Rack was not high enough for 5U.
2. 800VA Toroidy with 24V secondaries versus 20V. I was shooting for 28V rails, but with the highly efficient Toroidy and SLB supplies, I ended up with about 30V rails. Plenty of reserve, and I have yet to clip the amplifier driving it extremely hard.
3. I used Tom Christiansen's Universal Buffer (unity gain) and Preamp Power Supply to perform balanced to single ended conversion. Very nice pair that I have used previously in my preamp.
4. Miflex KPCU-03 versus VH Audio V-Cap CuTF to bypass V-Cap ODAM input caps
5. Audionote Kasei versus Nichicon Z for C111 bypass cap for the input LTP stage
Misc: Neotech UP-OCC stranded wire (22 thru 14 awg) throughout
LTP bias adjustment resulted in 2.7 mA per channel, with R/L DC offsets of 3.4 and 8.0 mV respectively. Heatsink temperature at base of Mosfets is running about 50 to 55 deg C. I am really enjoying this amplifier during the short time I have had it in my system. Definitely a keeper.
Steve
Attachments
zman01:
Thank you for the compliment. I am running GR-Research OB NX-Oticas with two triple 12-inch OB servo subs and two Power Sound Audio sealed 15-in subs.
It needs a dual rail PS, single +24V won't work. It is possible to do +/-24V with SMPSs, you just have to be careful you choose the right SMPS and wire them correctly https://www.diyaudio.com/community/threads/alpha-nirvana-39w-8ohm-class-a-amp.344540/post-6983476
What are the implications of running it with 50V rails? Just higher heat dissipation? Any other drawbacks?Hi Steve,
I echo everyone’s praises of your build. Superb workmanship. I think with 30v rails you may need to fix the label on the back panel though. It’s probably closer to 49w!
Congrats!
I'm using 2 laptop PSUs (20V each), only $20 on Ebay. Works perfect.
HP HSTNN-LA12 230W 19.5V 11.8A PC Desktop AC/DC PSU Power Supply Adapter
I’ve connected two SMPS bricks together in series as well for dual rail and it works very well as long as the ground from IEC is not internally connected to 0v output so they can be connected in series. Also, the laptop SMPS isn’t connected to a large cap bank as many go into hiccup mode if there is a larger turn on surge to charge the caps. It may think it is a short circuit and shutdown.
Nice thing about SMPS bricks is that mains 50/60Hz hum usually is non issue.
Thanks for posting that link Minek. 11A is a massive supply and suited for Class A loads.
Nice thing about SMPS bricks is that mains 50/60Hz hum usually is non issue.
Thanks for posting that link Minek. 11A is a massive supply and suited for Class A loads.