You should be, it looks stunning. Will Oak take a stain well? Before committing to Chrome corners try black ones to see how they look, chrome might detract from the beauty of the wood by being a bit bright and in your face.

I did wonder whether 3 conductors would do the trick only my electronics knowledge is not sufficient to have worked it out. I'm pretty much toed to 5 pin XLR's now since I've built the new footswitch, bought all the connectors to convert the original, my pedal board etc etc. And to think I could have got away with mic cable and a stereo jack socket.

Would you be so good as to show us how you wire the footswitch for this?

Many thanks

Hywel Harris

The warnings are there for a reason, BUT, the fact that you are being cautious to begin with means you won't be ignorant of the risks. Therefore you will be fine, don't delve into an ON amp, use your meter to check voltages to see how long they take to decay, if too long make yourself a discharge device (resistor and croc clips, effectively). I found with my OTS there was never any residual voltage after even only a few minutes.

Biasing is just a multimeter, twiddle the pot!! Plenty of material on the web to read about how to do it, or ask here nearer the time. One thing I did with my oTS, since I had way less electronics experience than you was to take it to an amp tech after completion for him to power it up and test all the voltages, then insert the vavles and bias it and fully test it. He only charged me £40, worth every penny for the piece of mind.

Go ahead, you'll enjoy it and the satisfaction will be immense.

Has anyone tried mic cables for the footswitch?. I wonder if the small conductors will drop the voltage too much and prevent the relay working reliably.

I don't think the JZ mods will have a great effect on the amount of break up, it didn't with mine when I converted it. One thing that will is the valve type in V1 for the clean channel and V2 for the OD channel. If you want less drive try a 5751 or Ay7 in V2. Also a 5751 in V1 will lower the overall gain for both channels.

PAB ON will drive the clean into break up a lot earlier. Make sure you have it turned off, the switches are counter intuitive (pedal postion is OFF)!. You'll know its ON if the tone controls have no effect.

Thanks Pickmaster. I just wonder if that cable has large enough cores for a 5m cable or whether I'm going to get too large a voltage drop. I've since found this

http://www.evelcables.co.uk/epages/Store2_Shop1476.sf/en_GB/?ObjectPath=/Shops/Store2.Shop1476/Products/SY5C0.75

but they want £10 for delivery for  approx £5 worth of goods!


By the way, when I did my mods I had to substitute some cap values since I couldn't get the exact same ones, but I guess thats not necessarily a problem, but with resistors I'm never sure of the voltage/wattage rating required. Nik uses three types the standard colour ring versions , Dale and another brown bodied one with writing on. Where would I get these in small quantities? RS won't do less than 25 a time of most stuff of this value. I got most of my caps from Hotrox as they are local but his stock of resistors amounts to 4 differing values!

Thanks again for posting those mods.

Nik if you are planning a Single ended amp, better if it could be around 10 watts or so. I have a 5w SE (Ampmaker) which started me off with this bug, but I find it a little underpowered for rehearsals with an overpowering drummer.

Just done the V1 and V2 mods today, leaving FET/Boost and Rock/Jazz switch mod for another day. Finished off a new footswitch with a 5 pin XLR socket on the switch so I will be able to swap cables easily.

Very impressed with the mod to V1 caps. Like it best with no cap in place of the .047. Much fuller sound.

V2 mods are a big help with treble on OD channel.

Anyone in the UK know where I can get 5 core flexible (and I don't just mean flexible like lighting flex!) cable for footswitches?. I'm currently using 7 core automotive cable but its a little too rigid, could do with something better.

Its got to be AB763 hasn't it!

How long have you had it? It will improve enormously when you have 30hours plus run time on the tubes with improved brightness and articulation, but break up will not really be affected. If what you describe as a 'good clean' is zero break up, you should get that without a problem, this is a very clean amp even up to 8 on master (not on O/D obviously!). What happens with pre at 8 and master on 3? What about pre on 3 and master on 8? That should tell you whether it is a pre-amp problem or not.

Hi Nik, how about having the plates made from some laminate material, with only the holes cut so that builders could just take the plate to the engravers for finishing?

Edit. Or perhaps you could make CAD (or PDF, AI etc) drawings available for hole placement?

Second that

Just turn it up some more then !!! LOL

Thanks for the clarification. I think I'm going to do the mods one at a time to get a feel for
what effect they have. First will be Rock/Jazz since that will be of greatest use for me.
The Boost control will also be very useful. PAB has always been a little too much
of a volume step with my TMB settings plus I have never had a use for the FET input.

Just a couple of questions about the Rock/Jazz replacement switch. Seems like a good idea to me
as I never use the Jazz setting.

You mention that the switching is Hi/Dumble/Plexi.
Am I correct in assuming that in the Dumble position, ie OFF, the trimmer controls the level of drive?

The two caps connected to the switch via the purple wire seem to be connected to wire X shielding.
Should they be connected to the signal wire of wire X? and what is their purpose since they don't appear to be connected
to anything at the switch?

Many thanks

Hywel Harris