It's impossible to tell where this vender gets their inventory but I've gotten some blatantly obvious fake Fairchild TO92s from them and they wouldn't even reply when I tried to contact them about it. They've been out of stock on Renasas LatFets for over a year so they obviously aren't presently a dealer. Now I'm assuming everything they are selling is fake or junk acquired from the scrap bin.
LatFets have a unique pin configuration so it's tougher to produce fake parts due to the odd die.
If there's a quick buck to be made someone will figure out a way though.
This amp is pretty impressive so far! I'm testing it with a Vertical VFA input. Sine and square waves are nice. The protection system is working flawlessly. It sounds great on my crappy little test speaker. I need to build a twin and get them in boxes with some proper supplies. My test supply is +/-63V but is sagging down to 55V at clipping. These screenshots were with a 4 ohm dummy load.
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55Vpk into a 4r0 test load is a mighty 378W
No wonder the PSU is sagging under that demand !
What is the rated output that you intended?
No wonder the PSU is sagging under that demand !
What is the rated output that you intended?
This will eventually be powering subwoofers in a home theater. Target output is 220W RMS at 8R / 350W at 4R. My test supply is using a 500VA transformer and 16AWG wiring. This will be replaced with a 1000VA transformer and 10AWG wiring so sag should decrease considerably.
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Getting 378W from your target of 350W amplifier is an achievement.
Your target of 350W from a 220W into 8 is set a bit low. That would be -1dBV into the halved resistance load.
Your 378W from 220W is improved to -0.65dBv
And if you get even better with the improved PSU then you are doing well.
I have this idea that current delivery into halved impedance is a good clue to the apparent bass from the amplifier.
-0.6dBv is very good.
-0.5dBv or better is excellent.
I think there are many here who criticise the bass performance of their amplifier and don't realise that it is probably lack of current capability that is the cause of what they hear. If they tested into lower resistance loads we would have some data to compare the audible effects that are reported.
Your target of 350W from a 220W into 8 is set a bit low. That would be -1dBV into the halved resistance load.
Your 378W from 220W is improved to -0.65dBv
And if you get even better with the improved PSU then you are doing well.
I have this idea that current delivery into halved impedance is a good clue to the apparent bass from the amplifier.
-0.6dBv is very good.
-0.5dBv or better is excellent.
I think there are many here who criticise the bass performance of their amplifier and don't realise that it is probably lack of current capability that is the cause of what they hear. If they tested into lower resistance loads we would have some data to compare the audible effects that are reported.
350W is my goal for the intended application. I think this will exceed that by a bit. Valery's design target for the amp module itself is 500W + at 4R. I have some higher voltage transformers I plan to test the module with to make sure it's able to produce that reliably.
I agree current available determines bass qualities. In a subwoofer application it is what determines weather you will have a box making booming noises or a subwoofer you feel.
I agree current available determines bass qualities. In a subwoofer application it is what determines weather you will have a box making booming noises or a subwoofer you feel.
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Hopefully I get some time to assemble and test some of the new input designs this weekend. I'd like to compare them too.
Ive used the Exicon Lateral audio mosfets and also Semelab Alfet but both of them are same sounding. When I tested a hexfet output stage with considerable bias. The transparency was very good in hexfet than in laterals. I have used laterals for over a 4 years now and now switching towards the hexfets.
Looking good
Clean, symmetric, fast enough step response, even with VFA front-end.
Seems to be a good solution for the cases where you need some extra power and/or you drive rather low, "difficult" impedance.
Great output current capability makes it possible to drive 2 ohm with no problem (some "difficult" speakers) - just take care of the swing in this case, driving 2 ohm all the way to the rails will be too much even for those 12 x MT-200 outputs 😱
I've seen AX-Deluxe
Because that and viewing the AX IPS- with less parts than other i am curiously to see test results. 😉
So that brings me back and i was reading from Lichtstark back here again and more options to combine with OPS.
So i collect needed information in a short Word Doc to work with. Schematic and Layouts extra.
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We've got a few new designs in the pipe, but those still need proper testing.
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The Vertical CFA is still my favorite input to date. It's very natural sounding. I have a backlog of Valery's newer designs sitting on the bench waiting proper testing though, so my opinion might change. The AX-Deluxe is very good too.Because that and viewing the AX IPS- with less parts than other i am curiously to see test results. 😉
So that brings me back and i was reading from Lichtstark back here again and more options to combine with OPS.
So i collect needed information in a short Word Doc to work with. Schematic and Layouts extra.
Thanks Jwilhelm, I quite like the small form factor of Marcs, makes it easier to fit on a heatsink and try an NS-OPS in future. Anyway, I'm tyre kicking, still need to finish a dac and pre. This will take a few months at the rate I work. But I am really keen to try some of these designs, or maybe a Slewmaster. I like the through hole and easy to get transitors of the Slew amps, but it seems Valery is a machine for new front ends🙂
Do you guys know where to get lateral fets for the tubsumo that are not fake? I think there may be a couple of ebay vendors that are trustworthy.
If you want original lateral nowdays you have only one choice.Exicon laterals.All other options is a high risk way.
Hi Thimios, thanks for the reply, but what about Reneas and there was another maker too, I cant recall the name, it starts with Alf or something.
You mean Semelab ALFET,ALF16P16W/ALF16P20W,ALF16N16W/ALF16N20W, yes is another option, Farnell stock them.
Unfortunately,no longer manufactured!
Look for a groups buy for Exicon here in the forum
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