Matchless/Bad cat build thread

[norburybrook]

I thought I'd start a new thread with the actual build process.

So, after deciding to go with this build the first hurdle is getting everything to fit in someway in a Chassis not designed for this particular amp.

I had to cut extra holes for a tube rectifier and an extra 12 AX7. This was done with a step drill.

Next challenge was to work out how to fit the EL34 cathode caps and resistors as they're huge. I came up with the idea of raising the power board with tall stand offs and having them underneath. I hope this is OK. There is plenty of vertical real estate as the main filter caps are actually quite small diameter.

I also had to mount the SS rectifier board 'Dumble' style as there was no other room.

with that all done I've started to solder and here's my progress today.

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M

[joeboo88]

Looking good.
I remember real estate was very tight. I did manage to get all in the same size chassis as you have.
I didn’t install the half power switch but I did like the tube/SS switch.
I like the tube rectifying side more.
You’ve got me intrigued again on this amp again. When I first built it I wasn’t very knowledgeable ( well I’m still not)
I am going to build one again, but only to 6v6 specs only. I have Iron suitable for 6v6 only.

Here’s a link to my original build. This was in RJs site... he started it when TAG had site troubles. Actually I have a lot of builds on that site, sadly not much goes on at RJs website anymore.
https://www.tapatalk.com/groups/diyguit ... 0-t77.html
Anyways good luck Marcus

[Synchu]

‘Now that I have a free chassis, do I need this?’
Looking good so far, however, I’d move the resistors, as heat tends to go up and these capacitors are very much exposed. They don’t do well with heat.

Niki

[norburybrook]

‘Now that I have a free chassis, do I need this?’
Looking good so far, however, I’d move the resistors, as heat tends to go up and these capacitors are very much exposed. They don’t do well with heat.

Niki

NIkki,

yes, my thoughts were twofold about this.

1: the chassis will act like a heat sink and

2: I'm building Tubes up like a Marshall so the resistor will be on top /capacitors below when it's in it's case



M

[norburybrook]

managed to get a few hours in today.

Finished the output section, including the SS/Tube recto and the half power switch.

Did all the shielded input wiring. I'm using Van Damme Patchbay cable. It's thin, Shielded, flexible , has a tinned core and lovely to work with.

I've done the heaters Marshall style i.e. not flown like Fender so I can get it out of the way early in the build

So, pre amp board to do now..........I've bought those very nice (expensive) Blue SOZO vintage caps.. to match the blue shielded cables

TBC.

Matchless 5.jpg

Matchless 7.jpg

M

[Colossal]

Looking good Marcus. I like the rear faceplate. Did you get it from Modulus?

[norburybrook]

Looking good Marcus. I like the rear faceplate. Did you get it from Modulus?

Thanks,

No, I got my graphics designer who does my CD artwork to do a pdf file from my drawing and measurements of the chassis and as I needed to get the transformer and other bits from Tube Town I got them to make it, otherwise Mike @Modulus would be my first port of call.

I had approached InMadOut to make transformers but I've a horrible feeling they may have gone under with the current situation, which would be very sad.


M

[norburybrook]

OK, a question:

While I was sat pondering how to do the heater wiring I thought, looking at the 4 pre amp tubes, the shortest path would be directly between the corresponding valve pins. i.e. you could take two straight line between very pin 9 and every 4/5 on each tube and have 'trainline' wires connecting the heaters. This would mean at least half the amount of wire used.

Twisting into pairs and going from the tube back to the chassis edge or flying over adds a lot of extra cable, do the benefits of twisting out way the extra cable length?




M

[pompeiisneaks]

I think the problem with that method is that you then need to run signal wires across the heaters. That's not a nightmare if kept at a good right angle, but it does add potential for noise.

It can't hurt to try it, though.

You also will somewhat have the two triodes wires running very close to one another, which might be problematic for oscillations unless all wires were shielded...

Just a guess.

~Phil

[didit]

Hello Marcus --

OK, a question:

Soldano did it with good success in SLO 100. Even bare wire, which gives tinkerers pause for concerns about shorting accidentally. Run close to the chassis floor and signal wiring floating vertically over.

Soldano guts.jpg

Best .. Ian

[norburybrook]

Ah yes....., exactly that.



I must have seen that before perhaps...bare wire? really?

So that begs the question , why all the trouble of twisting and flying or tucking away on the chassis edges?.


Tradition ?



M

[pompeiisneaks]

Yes pretty much. I did that sluckey's dual marshall build with the wires not twisted, just straight and laying next to one another and there's basically 0 hum.

There's more noise on the higher gain side, but it's the hash/hiss noise due to gain, no hum.

~Phil

[norburybrook]

Yes pretty much. I did that sluckey's dual marshall build with the wires not twisted, just straight and laying next to one another and there's basically 0 hum.

There's more noise on the higher gain side, but it's the hash/hiss noise due to gain, no hum.

~Phil

Having now done the heater wiring it's staying but if there is a next time and I find myself in a similar position then I will wire like Soldano.

Onwards and upwards.

p.s. I've a feeling Mike @Modulus amps wires heaters straight, perhaps that's where I'd seen it before, and I think he uses CA glue to keep them straight and neat. He builds a very tidy amp


M

[ChopSauce]

Yet another (forthcoming) great addition to your already convincing sonic palette ...

I'm looking forward to hearing the result, truely ...

Having now done the heater wiring it's staying but if there is a next time and I find myself in a similar position then I will wire like Soldano.

...

Aren't they wired straight (with solid copper rods) through bent connectors ?

[norburybrook]

well, I think I'm done with the wiring.

I forgot I was going to put a Line out on this when doing the artwork design so had to use the trusty old Dymo . Never mind.


There's definite Blue and Yellow theme going on here. I carried it to the wiring after I made the pre amp board and saw the Blue and Yellow Sozo caps.

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OK, time for a cup of tea then the light bulb limiter,,,,,,,,