Wizard MCII

[burger]

Thanks dude. I'll be in touch within a couple of days with details for the order.

[headcrash]

Awesome work with the PCBs, guys! Unfortunately I neither have the time nor the money right now to get one. Plus I would most likely rather make my own PCB with a smaller form factor, but that may or may not happen...

What I have done for the moment is butcher one of my older builts, which I didn't like quite much any more. It had a somewhat similar topology, or at least similar enough to convert it qick&dirty into a Wizard-(ish) amp.
I left out what I think does not contribute too much to the sound and am getting away with 4-stager plus a decent clean channel.
I had a hard time getting the Wizard bright control to sound good in that built. It always sounded choked to me. So I decided to use the barenaked 1n5 across the diode network like I did in my Jubilee clone. Plus I added a 2n2 across the bass and middle pots to ground (like in Jubilees or JCM 800 split channels) to tame the fizzyness I experienced. Worked out pretty good.
I had just enough bass, but without any bass headroom for open air gigs, where the lack of walls and corners lets some amps sound thin. So I used a Deep control like in Framus Dragon/Cobra but couple it with the bass pot (stereo pot). Works wonders and I have used it in several amps up to now with great results. Worked out great with that Wizard-alike.
All of that sounded really great and I took it to band practise last week. It sounded huge and I liked it quite a lot. But it didn't quite make its way through the wall of sound like my Jubilee clone does. Maybe a bit too compressed, still a bit fizzy.

Back on the workbench I decided to add a switch (relay) to the first cathode cap - and voila: gone is the last bit of fizzies, gone is the compression. Now it comes really close to the Jubilee in terms of immediacy, tightness and punch, but with more useable gain over the gain pot's range. I might switch in the first cathode cap for solos, which brings back the compression. But even without it, I have enough gain.
I am impressed that I am getting away with so little bass cut on the gain stages, but staying so darn tight. I always tend to cut lots of bass to avoid muddyness and get back bass behind the gain stages (and cut a lot of highs there again). Which is something that I kinda had to do in that Wizard-ish clone, too, but with much more better results.
The Clean sound stays really clean and sounds really decent. I 'd use the switching for the first cathode cap to comepnsate for the volume drop when using single coil pickups.
Two things I'd like to add in the future: a solid state FX loop, and a footswitcheable gain cut on the gain pot to have a crunch sound.

But beforehand, I still have to test it in band practise. Just wanted to share this now because I am really pleased with the results given the (small) efforts I had.
And - one more thing, I don't have a Wizard MC for comparison. I have no idea if this comes even remotly near to the original. I also don't have similar iron for the amp, it is a troidal PT with 320Vac for B+, and a standard MArshall 50 EL34 OT by Tube Town.
Take it as a proof of concept or feasablity study.

[burger]

Thanks to those who have grabbed one of my MCII PCB's - a bunch went out this week. If you ordered one, you'll have your tracking number PM'd by now.

20190711_075618.jpg

kdmay borrowed my MC25 clone, as shown in this thread, and posted a clip on youtube, check it out!!:
https://youtu.be/aq7xY8y-K6U

Still got a bunch on the MCII PCB's left, and also metro/friedman style loop PCB's - PM me if interested.

20190629_145543.jpg

[studiodunn]

Does anyone know what the Raw Bias voltage should be on a MCI 100w? I have rebuilt the bias circuit to 2203 specs and am sitting @ -44v. Does that seem low?

[kdmay]

Does anyone know what the Raw Bias voltage should be on a MCI 100w? I have rebuilt the bias circuit to 2203 specs and am sitting @ -44v. Does that seem low?

I would just stick the E34Ls and see whether it biases up. I'll check what mine is next time on the bench.

What is your plate voltage?

[BigFun3]

Pmed about boards.

[burger]

Update on my MC25...

https://youtu.be/xtmY-_LA3Wg

[studiodunn]

Update on my MC25...

https://youtu.be/xtmY-_LA3Wg

Are V5-V6 in the Wizard MC25 just For the loop?

[burger]

At least one is definitely for a tube buffered loop. In our design we favoured a LND150 based zero-loss fx loop, and shared the first gain stage between Rhythm & Lead channels which would account for an additional extra triode not being needed.

[burger]

New batch of MCII PCB's are in.

Minor changes from v1 of the board, this v2 now includes an additional aux relay and slightly improved on-PCB channel muting.

PM you are interested, I will ship worldwide.

[burger]

Just completed a 50w MCII for a local guy.

https://youtu.be/lqP_UqHT8M8

[studiodunn]

Just completed a 50w MCII for a local guy.

https://youtu.be/lqP_UqHT8M8

What trannies are you using?

[burger]

Classictone set for this one.

PT: http://www.classictone.net/40-18094.pdf
using the 710V CT

OT: http://www.classictone.net/40-18092.pdf
4k2 primary, M6 steel.

10Hy choke.

[studiodunn]

Is 400v stout enough for the choke?

And could the same 4.2k OT work for a 25W 6v6 build?

[burger]

Actually, this is the choke I used for the EL34 50 watters.

http://www.classictone.net/40-18032.html

The 10hy was for the MC25..

That OT is not suitable for a 6V6 pair, you need a much higher primary - more like 8k.