I used the usual 9240/240 combo. Matched for vgs between pairs and channels.
Good luck! Fingers crossed - but this amp is pretty safe and calm during initial turn on from the examples I have seen.
Interesting to see how the IXYS sounds. Which parts did you get?
It seems so
measurements seems to be ok, 0.6v across R131 and very little dc on output.IXTQ36P15P and IXTQ36N30P.
I was wondering that do I have enough pressure on mosfets, since plate that pushes them on copper/heatpipes gets hot like hell very quickly, while heatsinks don't heat up so quickly.
Are you using silicone heat sink spacers? I do find that torquing the bolts that clamp the MOSFETs down was important. One time I did not do it tight enough and smelled the funny “hot electronics smell” the one before puff of magic smoke occurs. I pulled the power off and discovered a loose bolt.
Tighten the clamps some more is all I can say. The clamps will get hotter because the heat to the sink and heat pipes gets dissipated very efficiently. Whereas the clamp has only slow local conduction. It may be fine. Do you have an iR thermometers? Measure MOSFET package temp.
Ok, hooked up speakers yet?
Another safe and uneventful adjustment-free Class A startup courtesy ALPHA topology.
Tighten the clamps some more is all I can say. The clamps will get hotter because the heat to the sink and heat pipes gets dissipated very efficiently. Whereas the clamp has only slow local conduction. It may be fine. Do you have an iR thermometers? Measure MOSFET package temp.
Ok, hooked up speakers yet?
Another safe and uneventful adjustment-free Class A startup courtesy ALPHA topology.
Yes, use this and dispense with balanced inputs (not needed on short cable runs).
Amazon.com: XM-R4-1 HIFI cable 2 XLR Male to RCA Male Quality Cables 2XLR to 2RCA, Dual XLR Male to Dual RCA, 4N OFC Wire XM-R4-1: Musical Instruments
Or if you are intent on using balanced, go in with an Xacto and cut the traces between C111 and C115 and GND, and wire the cut traces to -Ve input from the balanced line, replace C115 with same type as coupling cap on C1012(or whatever is used on input coupling - you need two of the same kind). Hugh can verify if I have this right, but I believe that is how you turn this into a balanced input amp.
Last edited:
Ok, made quick fix with 12mm aluminium bar. I have active system and tried it to lower end (20hz-800hz).
First: 96db/w speaker, this amp is quiet. Ear to cone and you can hear very very slight hiss, at 1m you can't hear a thing. Couple of songs and I heard things that I could not heard with darTZeel-clone. Bass..bass is really there, actually it woke up some room modes, I have little hot lower end setup by DSP, it seems I have to take it down a click have to say that I'm impressed. Theres defininetly a feeling a lot of power driving those JBL 2225's, who could guess that theres only 20w!
First: 96db/w speaker, this amp is quiet. Ear to cone and you can hear very very slight hiss, at 1m you can't hear a thing. Couple of songs and I heard things that I could not heard with darTZeel-clone. Bass..bass is really there, actually it woke up some room modes, I have little hot lower end setup by DSP, it seems I have to take it down a click
have to say that I'm impressed. Theres defininetly a feeling a lot of power driving those JBL 2225's, who could guess that theres only 20w!
Ok, made quick fix with 12mm aluminium bar. I have active system and tried it to lower end (20hz-800hz).
First: 96db/w speaker, this amp is quiet. Ear to cone and you can hear very very slight hiss, at 1m you can't hear a thing. Couple of songs and I heard things that I could not heard with darTZeel-clone. Bass..bass is really there, actually it woke up some room modes, I have little hot lower end setup by DSP, it seems I have to take it down a click
Juntuin,
Congrats on first sound! It is living up to expectations then? Obligatory photos of system please...
Cheers,
X
Juntuin,
Congrats on first sound! It is living up to expectations then? Obligatory photos of system please...
Cheers,
X
Thanks!
Defininetly a keeper! I can take some photo later today, altough I might take it apart and "build it right" later
Thanks X, Aksa and JPS64, really nice work with this one!
I think these are much better choice. Why? Because they use star-quad cables. And Neutrik XLR + Rean (Neutrik) RCA.
Pseudo Balanced RCA Phono to Male XLR Lead (PAIR). Van Damme Starquad Cable
-> Tour Grade Classic XKE Starquad microphone cable
or, in USA. Well, they are XLR - XLR.
Benchmark Studio&Stage™ StarQuad XLR Cable for Analog Audio - Benchmark Media Systems, Inc.
The Importance of Star-Quad Microphone Cable
The Importance of Star-Quad Microphone Cable - Benchmark Media Systems, Inc.
The video is very very very interesting!
Pseudo Balanced RCA Phono to Male XLR Lead (PAIR). Van Damme Starquad Cable
-> Tour Grade Classic XKE Starquad microphone cable
or, in USA. Well, they are XLR - XLR.
Benchmark Studio&Stage™ StarQuad XLR Cable for Analog Audio - Benchmark Media Systems, Inc.
The Importance of Star-Quad Microphone Cable
The Importance of Star-Quad Microphone Cable - Benchmark Media Systems, Inc.
The video is very very very interesting!
Last edited:
Got set up a bit better in my office to listen to the new alpha all day.
Linux workstation -> B1 clone -> alpha
Streaming FLAC from my NAS.
Slayer, NIN, Tool, Tom Waits, Hovhaness, some Bach, The Clash, and many others.
Ambient is ~21-22c.
Mosfets are sitting around 30-31c, and heatsinks just above the boards are ~31-32c.
I'll leave it on all day and into this evening and check the temperatures throughout periodically.
Linux workstation -> B1 clone -> alpha
Streaming FLAC from my NAS.
Slayer, NIN, Tool, Tom Waits, Hovhaness, some Bach, The Clash, and many others.
Ambient is ~21-22c.
Mosfets are sitting around 30-31c, and heatsinks just above the boards are ~31-32c.
I'll leave it on all day and into this evening and check the temperatures throughout periodically.
Juntuin,
Congrats on first sound! It is living up to expectations then? Obligatory photos of system please...
Cheers,
X
Congrats!!
Ok, made quick fix with 12mm aluminium bar. I have active system and tried it to lower end (20hz-800hz).
First: 96db/w speaker, this amp is quiet. Ear to cone and you can hear very very slight hiss, at 1m you can't hear a thing. Couple of songs and I heard things that I could not heard with darTZeel-clone. Bass..bass is really there, actually it woke up some room modes, I have little hot lower end setup by DSP, it seems I have to take it down a click
Excellent Juntuin!!
Glad to hear your powered up and enjoying music with your new ALPHA
The aluminum bar/clamp does get hot, but the cpu coolers work very well with a slow fan blowing across them.
Excellent Juntuin!!
Glad to hear your powered up and enjoying music with your new ALPHA
The aluminum bar/clamp does get hot, but the cpu coolers work very well with a slow fan blowing across them.
Nice to power up without issues
It's funny how those heatsinks are actually coldest place, clamp is MUCH hotter and capMX quite warm also. Effective little sinks. 140mm Noctua seems to work well and quietly. Toroidy's trafo is also super quiet.
Edit: I'm with higher bias right now, don't have right resistors at hands.