In preparation for the arrival of the DAS ST-215 and ST-218 loudspeakers, I purchased an MC2 4-channel power amplifier. It will be used to drive the 15″ drivers.
Picked one up yesterday, it’s an old solid-state model ca. mid-80’s – one of the JCM800 models, since I have not played an actual tube version of the JCM800, I don’t know if the SS version even comes close to the sound that it produces. Anyway, to my ears, it sounds better than the current SS amps that Marshall are selling – doesn’t hurt the amp is loaded with two Celestion G12M-70’s.
I just got a vintage Brunetti Mille from Italy, I believe this one is the original version which was modelled after the CAE 3+ SE. It is very well built and came with Ruby 12AX7’s. My initial impression of the unit is very positive, surely better than most of the amps that I have built myself… So the preamp stage do make a big difference, duh!
Before I bought the unit, I was think about building one myself, there are some kits on the market, but after factoring the cost and time, especially the front panel and chassis drilling involved – the price on the used Brunetti was simply too good to pass up. As much as I like DIY, there is no way to make it as professionally looking and robust (unless you have all the necessary machining tools and how to use them) as the factory built unit.
Below are some pictures that I got from net, I actually quite like the unusal blue color of the front panel, it reminds me of the old Orban equalizers that I used to work on – and perhaps will acquire one of these days if the price is right.
I got one today with the intention of modifying it into a Tweedle Dee, but before I do that I will play with it for a few weeks, perhaps changing out the speaker and see if the tone could be improved – even with a 15″, the amp still sounds bright to me…
I was thinking about modifying the VK212 when I first got the amplifier a few months ago, and came up with some potential modifications. But at the end, I abandoned the idea and went with a near-scratch build – I took out all the PCB’s, and put in a Marshall 2446 Vintage Modern clone in their place instead. This worked out great, since the chasiss has quite large so I had ample room to work with. Of course, I re-used the PT and OPT which were perfectly fine. I also saved the PCB’s from the VK in case if I ever want to put them back (which I doubt seriously). The only tricky bit was to modify the heater supply, since the VM uses one extra 12AX7 tube than the Vk212.
I don’t really like the series heater arrangement in the VK, however the PT came that way, and I did not want add another filament transformer to the chassis, so it would have to do. Of course, the disavantage is if one of the tubes go bad, the whole amp will be out of commission. Since it is just for home use, it is not a really big deal, but I would not want to take it on the road.
Instead of the 6L6’s that came with the amplifier, the output tubes have been changed to the 5881’s that I have laying around, so the output power was lowered to about 75W. I also took the opportunity to add a bias adjustment board, which is the small board mounted above the power tubes that you see in the photo. It came from a scrap’d hi-fi amplifier. With the board, each of the output tubes could be biased individually, which was sorely missing from the original VK212.
With the existing VK speakers, the amp sounded a bit bright to me, then again, I haven’t spend much time with it…
Here are some photos from the build:
I completed the ODS build a few months ago, here are some photos. I got the chassis from RJ Guitars, and the purple head shell from Glassworks, thanks guys.