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This is a quick lash up of my latest project, a copy (ish) of the Blackstar Dual-HT. I found a schematic on the net of an early version that uses 22v AC. when I finished it I had hum problems. The BS version has halfwave rec and this was a problem and so I converted it to DC. The pic of the low voltage board shows two 15v regs but it# is a bit different now because of this change. The PDF schematics of MY version are here Schematics These are the changes I made: 1) I only wanted one channel so I deleted channel 2. 2) Didn't like treble/bass design and also that bit uses a two gang pot and space was limited and so I replaced it with a Baxandall circuit. 3) Bypass is true bypass. 4) I couldn't get all the jacks on both sides and so they are on one side and with no room for a CAB jack I used a phono type. 5) If the BLAGSTAR is not in BYPASS it lights up blue as you play. 6) MAJOR MOD!!! The LEVEL control now goes up to 11. Awesome eh? Click on any image to see a bigger version.
I made the grille first. It started as an alu tube. After cutting the slots and then the tube I opened it up and twatted it with a hammer a few times. It is covered in a chrome tape I bought at a car-boot last year: I knew I would need it one day. The red legends are printed and then sprayed with a laquer.	The boards (2) were made up as a sort of module that could be dropped into the case. The valve can be changed through the top by removing the grille. Behind the valve you can see a heatshield. I have seen pics of a make called 'Blackstar' which look similiar to mine and in some the pcb is scorchio mucho.	... and then it fits inside like this.	The valve board can be run on its own from 22v. This let me build and test it on its own.
This is the valve board fitted with the heatshield too.	The top board was also designed to be testable on its own. I use a jumper when the valve amp is not fitted. There is a loss of gain but it was easy to debug the well packed vero!!!	When useing Vero I only ever wire supply pins on the comp side and do those first, with decoupling. Unless I need a shielded wire all the hook up takes place underneath. Do not use a spot cutter for stuff this tight, a scalpel cut across a hole leaves a lot more track to solder to. So these are the tracks of my tears, it was a bit of a Miracle...	Serious upgrade!! The Level going to 11 ...
Yes, power was a problem due to AC hum. My mod was a simple 555 to generate the 10mA of -V. In fact you get about -12v but the op amps never get anywhere near this swing. DO NOT ommit the R on Pin3 of the 555 -- I blew eight 555s before I realised why! Doh! And so all it needs is an old Laptop PSU 18-24v ish. You need to change the plug because most pedals connect the out barrel to +V.	So here it is then And playing with a blue led. A long time ago I discovered that everything needs a blue led to work.