Hi X,
my first though if i see this Collection.
Good Resumee for end of a good Season.
Don't let stumble Terry to see your Collection.
Cheers.
There's no competition with Terry - he's the undisputed king of amp building for sure.
All this started just last March and has been a blast learning from all of the experts here. A big thanks to Prasi, Sonal Kunal, Idefixes, Dacz, Kees52, and Jkeutermann for providing me with such great Gerbers that made this possible. Also, a huge thanks to the great designers of the circuits that I built with Apex Audio and Nelson Pass as probably the leading sources of inspiration that got me to start building amps.
Not shown below are CFH9 (currently in the hot seat), VHEX+ (in a case), F5HA with IRF610/9610 (in case), and ACA deadbug (at office). My journey was (as best as I can remember) as follows: Dx, ACA P2P, Inv JFET Circlophone BJT OPS, DOS TDA7297 w shunt reg, FX8 50mm - Sonal layout, FX8 Bimo - Prasi layout, VHEX+, FH9, FH9HV, VSSA JK thru-hole, Inv JFET Circlophone MOSFET OPS, Ranchu/Aksa Quasi - Prasi layout, Apex AX11 - Prasi layout, M2 - Teabag layout, Kees52 allFET Circlotron, CFH7 - Idefixes layout, Ranchu/Aksa Quasi - Dacz layout, Juma F5 2SK2013/2SJ313 - P2P, F5HA - P2P, CFH9 - Idefixes layout, F5HA - Prasi layout, F5HA 2SK2013/2SJ313 w Juma shunt reg - Prasi layout.
Had a couple of VSSA kits as seen below that was handed over to X so his amp build into 2016 and shared sound clips will probably soon grow by one more
(Was so happy meet xrk971 and member wesayso in person couple of days ago when X was at a business trip to Netherlands http://www.diyaudio.com/forums/full...er-full-range-line-array-275.html#post4904679).Attachments
Had a couple of VSSA kits as seen below that was handed over to X so his amp build into 2016 and shared sound clips will probably soon grow by one more
Hi Byrtt,
Yes, thank you for the amps Byrtt! I will have one more to add to the collection and sound clips. It looks like a pretty straighforward final assembly to solder actives in place and add caps and heatsink.
The brief meeting we had at Wesayso's house was indeed a day to remember!
I also have a new head amp I just got working: a zero feedback MOSFET class A source follower that uses a LU1014D power JFET and IRFP240. Sounds fantastic but is a real house heater with 13 watts of thermal out for 330mA bias current.
http://www.diyaudio.com/forums/head...lower-headphone-amplifier-14.html#post4906102
It is a superb amp - absolutely noiseless, no hiss, no hum, nothing audible when music is not playing. Very direct and deep deep bass when using low impedance headphones.
Real PCB should be on the way:
New head amp looks good and heater effect is useful into wintertime
, when time comes have fun building VSSA kits.Xrk, wow...Iam just getting to listening to these.
To me, the vhex seems the most well rounded, perhaps a little dull on top. Great bass though. But to tell you the truth all the amps seem similar except the m2 and the circlophone. Circlophone sounds like a tube amp and the m2 sounds more forward than the rest. And something is different than the others in the midrange...sounds more close miked than the other amps. Actually sounds a bit unrefined but maybe the most fun, which was unexpected. I'd like to see a pass f5 or aleph throw in the mix...
To me, the vhex seems the most well rounded, perhaps a little dull on top. Great bass though. But to tell you the truth all the amps seem similar except the m2 and the circlophone. Circlophone sounds like a tube amp and the m2 sounds more forward than the rest. And something is different than the others in the midrange...sounds more close miked than the other amps. Actually sounds a bit unrefined but maybe the most fun, which was unexpected. I'd like to see a pass f5 or aleph throw in the mix...
You must have a lot of free time or a time machine. Thats a lot of amps in not a lot of time.
Iam currently running an f5 with two pairs of toshiba mosfets and salas' SE preamp. Sounds great but I am looking for more power (87db 3 ways in a big room). Iam interested in the vhex amp...but coming from the pass philosophy I have a bias against heavy feedback and low output stage bias.
Your test was interesting and confirmed some of my preconceptions...the no/low feedback amps (especially the m2) sounded more lively and less refined. And the m2 is supposed to be the mellowest of the first watt amps. Not sure what I like though...and that's the problem. Might try the vhex and see...
Iam currently running an f5 with two pairs of toshiba mosfets and salas' SE preamp. Sounds great but I am looking for more power (87db 3 ways in a big room). Iam interested in the vhex amp...but coming from the pass philosophy I have a bias against heavy feedback and low output stage bias.
Your test was interesting and confirmed some of my preconceptions...the no/low feedback amps (especially the m2) sounded more lively and less refined. And the m2 is supposed to be the mellowest of the first watt amps. Not sure what I like though...and that's the problem. Might try the vhex and see...
So the M2 sounds forward only in the mids or in both the mids and highs?
What do you mean by it sounding a bit unrefined?
Thanks.
Mids. Forward vocals too. Sounds just a little less sophisticated than some of the others, and it seems a little less 3d in depth. A little less liquid also. Also, the vocals have less body. But it does sound more lively and lit up and interesting. I wonder what psu xrk is using because that is what some of the pass amps can sound like with undersized psu or low bias.
Still one of my favorites though. Iam listening on headphones which don't show me imaging, etc.
[QUOTEYou must have a lot of free time or a time machine. Thats a lot of amps in not a lot of time.[/QUOTE]
The time machine = less sleep
The PSU for the M2 is a whole topic in itself. I was using a 400VA 18VAC toroidal transformer from Antek with dual 4x33mF CRC's. But I had some noise issues. They are somewhat resolved, but still can't beat dual 24v 5A SMPS bricks in series for clean power. It may be that my transformer is saturated with local line voltage at 120vac. It's still on 400VA Antek but with improved grounding scheme and I am using the Project16/Prasi Class CRC PSU now. I am also using proper ground loop breaker and star grounding topology.
http://www.diyaudio.com/forums/power-supplies/306411-strange-forest-noise-linear-psu.html
Current PSU is:
http://www.diyaudio.com/forums/group-buys/301682-crc-power-supply-class-amplifier.html
The VHEX+ is a fine sounding amp, and is my main amp that is a fixture. However, it sounds much better with the Aksa CFP 2SA1837 preamp. More engaging and nicer feeling of naturalness. I use Abletec 53v SMPS for the VHEX+ with a pair of 4x9.6mF CRC's as final filter between the SMPS and the amp.
The time machine = less sleep
The PSU for the M2 is a whole topic in itself. I was using a 400VA 18VAC toroidal transformer from Antek with dual 4x33mF CRC's. But I had some noise issues. They are somewhat resolved, but still can't beat dual 24v 5A SMPS bricks in series for clean power. It may be that my transformer is saturated with local line voltage at 120vac. It's still on 400VA Antek but with improved grounding scheme and I am using the Project16/Prasi Class CRC PSU now. I am also using proper ground loop breaker and star grounding topology.
http://www.diyaudio.com/forums/power-supplies/306411-strange-forest-noise-linear-psu.html
Current PSU is:
http://www.diyaudio.com/forums/group-buys/301682-crc-power-supply-class-amplifier.html
The VHEX+ is a fine sounding amp, and is my main amp that is a fixture. However, it sounds much better with the Aksa CFP 2SA1837 preamp. More engaging and nicer feeling of naturalness. I use Abletec 53v SMPS for the VHEX+ with a pair of 4x9.6mF CRC's as final filter between the SMPS and the amp.
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So, I just went back and read most of this thread. Also, I didn't see that clips of Juma's F5 were included so I went back and listened to those too. I am using clip 3 primarily for this test.
Sounds like the Pass amps (M2 and Juma's F5) are more forward and lacking some detail compared to Vhex and quasi and FX amps. I know you (XRK) are using unmatched devices from dubious sources for the input jfets...I wonder if this is the problem? Those Toshiba devices are often faked. And unmatched outputs on the Juma's amp will lead to higher 2nd harmonics and maybe bias instability or inability to achieve a good high bias.
Those issues aside, I still wonder if a lot of this is topology differences, feedback differences or what. It's a good test and probably more informative to be in the room instead of headphones. It's sometimes hard to predict imaging and sense of space through headphones. From this test it's hard for me to say that the class A amps (M2, Juma's F5) were the best, which I thought I would have preferred. It's made me think a little bit about A/B.
Nice work XRK.
Sounds like the Pass amps (M2 and Juma's F5) are more forward and lacking some detail compared to Vhex and quasi and FX amps. I know you (XRK) are using unmatched devices from dubious sources for the input jfets...I wonder if this is the problem? Those Toshiba devices are often faked. And unmatched outputs on the Juma's amp will lead to higher 2nd harmonics and maybe bias instability or inability to achieve a good high bias.
Those issues aside, I still wonder if a lot of this is topology differences, feedback differences or what. It's a good test and probably more informative to be in the room instead of headphones. It's sometimes hard to predict imaging and sense of space through headphones. From this test it's hard for me to say that the class A amps (M2, Juma's F5) were the best, which I thought I would have preferred. It's made me think a little bit about A/B.
Nice work XRK.
Very possible. Don't think I've heard anyone complain that one of Pass' designs lacks detail. At least, not if the build was properly executed and used the proper parts.
Iam not sure...in this case it kind of makes sense. The transformer input of the m2 would acoount for lack of detail...the more complicated vas in the a/b amps could perhaps be more transparent than the f5.
My experience has been that the class a amps have a more reach out and touch the sound sort of presentation. It's hard to tell with headphones. Basically to me, this is a tonality test through headphones...which I don't really trust mostly because I much prefer speakers.
Also, the testing is done at a 8 ohm load, I am not sure of the spl at listening position. With a harder load and more spl the results may be different.
My experience has been that the class a amps have a more reach out and touch the sound sort of presentation. It's hard to tell with headphones. Basically to me, this is a tonality test through headphones...which I don't really trust mostly because I much prefer speakers.
Also, the testing is done at a 8 ohm load, I am not sure of the spl at listening position. With a harder load and more spl the results may be different.
Maybe. Like you say, it is hard to tell via a recording.
I've heard great detail and tonality using a Cinemag transformer as the gain device, but can't speak for the Edcor used in the M2. It is a much loved amp by Zen Mod, though. As for the F5, my DIY version is one of the most detailed amps I've built. It has excellent mids and highs, but is oddly a little bass light in my setup.
I've heard great detail and tonality using a Cinemag transformer as the gain device, but can't speak for the Edcor used in the M2. It is a much loved amp by Zen Mod, though. As for the F5, my DIY version is one of the most detailed amps I've built. It has excellent mids and highs, but is oddly a little bass light in my setup.
More bias, more capacitance and more mosfets helps the bass in the f5. I went from stock to 2.5a bias, 2 pairs of mosfets and more capacitance and it's a different amp.
But 25 watts is so is ultimately less than I need. So Iam interested in the vhex.
Gotta hand it to xrk...this is about as close as you can get to hearing these amps without having them in the same room. He's done a big favor for us. It's really interesting and valuable.
I had a friend listen who is not an audiophile but is a musician. His preference was the m2. Maybe because it was the most different. He did comment that all of them are very close, much closer than he expected. Actually, they are all much closer than I expected as well.
I hear F5 amplifier who built by my friend. He used boutique components. The low is super, very good. The mid is good, but the high is not good enough for my taste.
Thanks for the positive comments Hikari. Glad you find this helpful. Regarding unmatched devices - one reason why I want to do a Pass F5 with the original single IRFP240/9240 MOSFETs. I would have guessed the F5 would have lots of detail as it probably has a bit higher third order harmonics based on the topology. I know the F5 headphone amp is very detailed. I actually prefer SE Class A now in general or anything designed by Hugh Dean, whether Class AB or SE Class A.
I do agree that speaker amps should be at least 50w if you don't have the high sensitivity full range thing going on. Typical multiways are in the mid 85dB or lower and need some juice to come alive. In this sense, any clean and direct Class AB is a good slave to a SE Class A preamp Master.
I do agree that speaker amps should be at least 50w if you don't have the high sensitivity full range thing going on. Typical multiways are in the mid 85dB or lower and need some juice to come alive. In this sense, any clean and direct Class AB is a good slave to a SE Class A preamp Master.
I think the true original used some now discontinued Fairchild parts. The published DIY version uses the IRFPs because the Fairchilds vanished.
I've been meaning to build another using IXYS IXTQ36N30P/IXTQ36P15P. They are a pretty good complementary pair and offer considerably more transconductance as well as a lower thermal resistance than the IRFPs. I'm curious how they would sound as gain devices in this simple circuit. They perform superbly as source followers in my current mirror amp.
xrk971 said:
Not necessarily true. Transconductance mismatch between the complementary pairs can easily lead to a second harmonic dominant amp. Alternately, one can build a version which offers some degree of an adjustable distortion profile.
All this started just last March and has been a blast learning from all of the experts here. A big thanks to Prasi, Sonal Kunal, Idefixes, Dacz, Kees52, and Jkeutermann for providing me with such great Gerbers that made this possible. Also, a huge thanks to the great designers of the circuits that I built with Apex Audio and Nelson Pass as probably the leading sources of inspiration that got me to start building amps.
Not shown below are CFH9 (currently in the hot seat), VHEX+ (in a case), F5HA with IRF610/9610 (in case), and ACA deadbug (at office). My journey was (as best as I can remember) as follows: Dx, ACA P2P, Inv JFET Circlophone BJT OPS, DOS TDA7297 w shunt reg, FX8 50mm - Sonal layout, FX8 Bimo - Prasi layout, VHEX+, FH9, FH9HV, VSSA JK thru-hole, Inv JFET Circlophone MOSFET OPS, Ranchu/Aksa Quasi - Prasi layout, Apex AX11 - Prasi layout, M2 - Teabag layout, Kees52 allFET Circlotron, CFH7 - Idefixes layout, Ranchu/Aksa Quasi - Dacz layout, Juma F5 2SK2013/2SJ313 - P2P, F5HA - P2P, CFH9 - Idefixes layout, F5HA - Prasi layout, F5HA 2SK2013/2SJ313 w Juma shunt reg - Prasi layout.
You built so many different amplifier, can I suggest one for you may be you will be interested. Something very different
Please PM if you interested
By the way which one is your favorite. I mean if you have to use it at the rest of your life and must pick one..
Greetings
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