That's why I made index thread. Look in post #1 it has links to schematics and Gerber files.
http://www.diyaudio.com/forums/solid-state/292226-directory-apex-audio-amplifiers.html
Please explain what method you used to determine that the version with the vertical MOSFETs is superior in sound quality. Did you use any type of blind testing?
I explained this before - you must have missed it. I can hear it - and it's substantiated when I look at the measured frequency response of the speaker as played by the amp. There is maybe a bit more reach in the low end on my sealed woofers. 24liter RS225-8 seems to have maybe extra 1.5dB down at 50Hz.
I'm not the only one who thinks IRFP240/9240 has better bass than 2SK1058/2SJ162.
Although with the VSSA the lateral FET seems to have pretty good bass - hit then I haven't compared to a VSSA that is running with hexFETs. The CFH7 might be such an amp if we ever get around to getting a layout for it.
I'm not the only one who thinks IRFP240/9240 has better bass than 2SK1058/2SJ162.
Although with the VSSA the lateral FET seems to have pretty good bass - hit then I haven't compared to a VSSA that is running with hexFETs. The CFH7 might be such an amp if we ever get around to getting a layout for it.
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OK, so you are basing this on memory not an actual blind test. How much music material is at 50hz? Most recordings are rolled off down there to reduce rumble. Your'e not using this for a sub woofer are you?
55Hz is the fundamental of the kick drum and is about where you want a speaker to reach to be considered "full range". I am not using this to drive a sub.
thank you
i will test it
i need a good DC and short circuit and over curent protection for this amp too
What what are the parameters? How many watts do you need? Will you be driving strictly 8 ohms or will you maybe drive 4 ohms in the future? What kind of power supply will you be using? Some of the models have better PSRR. The original AX14 is great. I would suggest you use the thread that xrk971 created and go to a few of the different amps and do a little reading. I have built most of them but I don't remember which ones were the easiest to set up and most stable. They all sound wonderful so to me it comes down to stability, availability of parts power needed and ease of use. YMMV
Blessings, Terry
Hallo
There are any members who can explain us for our understanding?
Cheers Bangla.
Could be the reason better gm of VFet?- and relativ lower damping to speaker- bit less controlled?
There are any members who can explain us for our understanding?
Cheers Bangla.
How many watts do you need? more than 130 watt
Will you be driving strictly 8 ohms or will you maybe drive 4 ohms in the future? 4 ohm in max
What kind of power supply will you be using? push pull switching
it must be stable, strong, easy to setup, full protected, very clear sound and best in quality sound for 50HZ -- 20KHZ
i do not use it for subwofer.
thank you and other friend for helping
i want use tube amp before. they have very low THD .
i want crate an tube peramp for apex amps
thank you.
i want crate an tube peramp for apex amps
thank you.
OK I looked back through some of my Apex amps and I think the SR150 would fit the bill for you. Very stable and 150W into 8 ohm. You will need close to +-50VDC PSU to get the 150W/8R.
a 35-0-35Vac transformer giving ~±50Vdc will get 100W into 8ohms from a BJT or low loss mosFET amplifier.
Only about 80 to 90W from a normal mosFET amplifier.
You will need at least a 40-0-40Vac transformer giving about ±58Vdc to ±60Vdc to get close to a 150W into 8ohms target. Maybe a 41Vac or 42Vac could hit the 150W target.
Strange, SKA-GB150 is touted as a 150w amp and Greg says not to drive it with anything more than +-50VDC
He may be referring to it's maximum power output capability.
It certainly cannot do 150W into 8r0 from ±50Vdc
The SKA is a low loss mosFET output. So it can challenge and maybe beat BJT for max output from a given rail voltage.
It certainly cannot do 150W into 8r0 from ±50Vdc
The SKA is a low loss mosFET output. So it can challenge and maybe beat BJT for max output from a given rail voltage.
I guess I will have to hook up my SR150 and see what kind of rail it takes to get 150W. I has been a log time since I tested it.
Well, I have a 300W 8R load and a scope. I think I will do my own testing. We will see how good your math is. Like I said, Greg says to not drive the SKA with more than +-50V so I guess we will never know on that one.