Moskido - Hybrid Aikido/MOSFET amplifier

[beau2317]

I used to listen to a variety of SET amps, but the my moskido bests them on everything now just about. But it's quite tweaked up - vishay resistors, mundorf caps, auricaps in the PSU, Blackgate and big auricaps on the output, etc.

[beau2317]

QuinnLing : I would be interested to hear your experiences, and please post your circuit.

Thanks
bob

[kmtang]

We all saying that the amp of mine is the BEST.

Well, I would say it is just matter of different taste of individuals. If you enjoy it, it would be the best.

Enjoy the music and explore whatever would bring the music live.


Johnny

[beau2317]

We all saying that the amp of mine is the BEST.

I am not saying my amp is the best. What I am saying is the moskido I have is the best amp I have heard so far.

I have tried personally the following in the last 5 years:

4 SET amps (dual 211, 300B, etc)
2 other "good" tube amps
3 hybrid amps (tube/mosfet)
2 solid state amps
4 class D amps

That makes 15 different amps in 5 years. Yes I am probably a bit mad.

I've also heard a bunch of other amps in other people's systems, which is harder to judge, but my feeling is that none come close.

That's just my thoughts. If I knew a way to make a better sounding amp I would build one tomorrow. But right now I have no idea how to improve on this.

[quinnling]

Bob,

You can find the schematic for the F4 in this thread:
F4 power amplifier

I have the Octal Aikido Boards, I may use 12SL7 as the gain and 12SN7 as the driver.

I also have 6BX7 tubes on hand, but the 6SN7X/6H30PI-OCTAL) that Broskie sells seem like a great tube.

Quinnling

[sandro600]

beau2317,

I would like to build the moskido.
The only thing stopping me is how to build the build the power supply.
Could you post a cookbook recipe for how to do this ?
And how to link the PSU to the PCB
I have the outline of components you suggested earlier in the thread.

Thanks

[sepolansky]

Hi,

Just joined the forum. The Moskido sounds like it might be up my alley. I need lots of power to drive my bass panels (Tympani IV). I have a couple of DH500's which use the Hitachi lateral MOSFETS. I wonder if the Aikido front end could be adapted to drive six pairs of these (or half that If I don't build them as monoblocks) considering the +/-80V power supply? Can the driver stage swing adequate voltage to drive the output stage to full power?

sepolansky

[beau2317]

It sure can swing enough. How about plus/minus 40V. Or 80V. Depends on what signal you feed it. Using 6SL7 it has a gain of about 30, so as long as you drive it hard enough, it will swing pretty much as much as you want.

You won't have to worry too much about the mosfet capacitance if you are only driving bass panels; a bit of HF rolloff will not hurt you.

Cheers
bob

[sepolansky]

Bob,

So, since I want to use my existing power supply basic components, would I reconfigure the supply as monopolar 180VDC? (Oops, I said it was +/-80 volts before; now I checked the schematic and see that it is actually a +/-90 volt supply!) (I certainly will embellish the supply with bypasses and additional capacitance, but a regulator would be a bear!)

The bias string resistors: how critical in value are they? Should I just scale them for 2.5x the B+ supply voltage? Sorry, I'm not quite sure of the purpose of the configuration.

I'm thinking of using 9-pin tubes. I have an unused Aikido 9-pin board and lots of 12AX7's, 12AT7's, 5687, ECC99, etc. that should do very well for up to ~300Hz. What do you think?

Stuart

[beau2317]

I had this report from one Moskido builder

My Moskido has finally finished and been playing for about 200 hours. It generally did surprise me from the very start. The sounds go deep and wide with lot of power and kick. It sounds so delicate in highs and the mids are admirable but a bit hush. The bass is good and deep and powerful which I could easily identify the different between a bass guitar, the double bass and the kick of drum. I specially like the kick drum which is so real and with a life like feeling as if somebody playing in front of me. My friend Johnny said the sound is so big and wide as if we’re sitting in the Silver City. After the first week, I tweaked it with Riken and Vishay resistors, and Jentzen caps for coupling. I put more capacitance at the output and make it a total of 2000uf Blackgate in series with 80uf pp Murdrof and 8uf paper in oil in parallel. The result is better than expected. We can find the highs are more detail and delicate to transparent, the mids are smooth a bit but there is room to improve, and big improve at the lower spectrums which present in layers and punchy. This amp belongs to another class. It consists the best of both world. I have been listening to many big names and have built some 300B, 2A3, 6550pp, EL34pp, KT88SE and pp, and some 100W class A Mosfet. All in all the performance of the amp is phenomenal. It does have the ability to drive the low db speakers and the ability to recover those weakest notes which I have been loosing for so long. And that supposed to be part of the music for us to enjoy. Now, all the members of the orchestra are playing for me, and I enjoy every minute with it.We took the amp to compare with Mc 275, Mz 9 and 8, Ja 80 and M.L. 3. The amp basically very much can compare with those big names. As per my entire friend’s judgment, It only inferiors a bit thickness and lush in mids to Mz 9 and Ja 80, and the weight of bass to M.L. 3. But, with that little money I spent. It does make those big names embarrasses.I still love the mids of the Askido 300B with the horn set-up. I thought this is good to have the Askido 300B to compare with the Moskido, so I could make improvements. Will certainly inform you when I can make the moskido sing as warm and smooth as my 300B.