Guitar Gear Forum

I'm smack in the centre of Wakefield but I'm originally from Huddersfield.

I got recommended Pennine Radio by Hayden Minnet who works at Matamp & owns Bulldog pickups. I still haven't actually got anything from them though.

Small world ey!

Looking good. Always enjoy seeing your work. Very nice.

Finally got my workshop set up. Tonight I'm going to reroute some of the wiring and try mounting the tube sockets for cleaner wiring. Since I'm only putting a cathodyne PI and maybe an input buffer stage in now I have the space to play with so why make like difficult?

ah, cant see any pics. what image hosting are you using?

I only stuck them on facebook

OT and PI board installed now. I have a problem with the heaters that I need to debug tonight. This is mainly due to antek's less than helpful wire colour scheme. I just need to to try a few different combinations on a screw terminal strip to find out what is supposed to be going where.

*grumbles*

pics dude, pics.

Wired in the OT and did a general clean up of the wiring now I know the power supply is solid. Next job is to wire up the sockets and bias supply.

Bias circuit, PI and poweramp wired up. I just need to make and wire an input buffer and hook up the feedback loop and its set to test.

It fucking lives!

It gets loud with just my strat driving it Next up I need to add the NFB loop and controls and the reduce the screen voltage slightly. The transformer isn't sagging at all so its running the screen filter cap critically close - thus the reason for dropping it.

Once thats all done I'll box her up and start on the rack preamp.

My bud is knocking a headshell together for me. It's not going to be fancy. Its purely for protection in transit and y'know, so I can actually take the thing places.

Next job is to start designing the nuts and bolts of the preamp so that the layout can be done. First thing is to think about is where the transformer, main PSU boards and the tube sockets are going to live. Thankfully the PSU board is going to be quite small as its only a preamp so not much more than reasonably large filter cap and heater elevation is needed here. I've looked to the x88r for inspiration here. I'm not using a centre tapped transformer so my take is slightly different. I have a 15VAC secondary for adding relay switching and what not which will be regulated to 12VDC. This will probably live on a small bit of perfboard as initially I'm not too worried about adding switching in. The big bit here will be the tube sockets. In the past i've used a L bracket to mount the sockets for preamp build but thats not too friendly for prototyping as I dont want to have to keep making connections to the socket tabs as they'll eventually fail and then I'll need to replace then and that will be a pain in the ass. Instead I've decided to mount them vertically on a small break board which has turrets for the each of the connections. I've knocked together a quick sketch and it looks something like this:



A guy who made a turret x88r did something similar and its a pretty near way of doing it. I've decided to use some Belton sockets this time rather then the Chinese ceramics I have used in the past as they are a pain in the dick to work with as the mounting lugs are very close to the socket. The heaters will be run straight & parallel like in the SLO as its easier and neater. I'm elevating the heaters by 70-80VDC anyway so noise isn't a concern.

Great thread and awesome build! Gotsta get me a man cave and build an amp! Unfortunately, the lady of the house has taken over... even the garage!

So I've had a bit of time to poke at this. Staked the output buffer board last night and hopefully I'll get a few hours in at the solder station to get the PSU and buffer board populated. I want to get this off my bench in the next few weeks so I can start on a new super secret project

Power supply board populated. Tonight I hope to get the buffer board populated.

Looking good so far. =)


I'm planning on building a tube amp myself from scratch in the next 1 or 2 years.

Any tips to someone very, very newbie and unexperienced with electronics?

Do as much reading as you can. You want to be able to look at a schematic and know what every component does - This makes debugging a hell of a lot easier.

Here are some great resources:
http://www.valvewizard.co.uk - Merlin is the man. His preamp book is excellent and a great source of information and ideas.
http://www.ax84.com - The forum is very good and has lots of knowledgeable and helpful members. The P1 theory document is a great read.
http://music-electronics-forum.com - Probably the best forum, covers lots of aspects of design and building.

Unless you're particularly brave I'd start out with a kit. A good one will come with instructions and a building guide which will be useful as it's not obvious how some things are best done and in what order they should be done in. I do scratch builds using blank chassis' and the hardest part is the layout. Having this part done for you in worth its weight in gold as bad layout will be a self oscillating mess that is a nightmare to debug. What sort of thing do you want to build?

Zozobra wrote:Do as much reading as you can. You want to be able to look at a schematic and know what every component does - This makes debugging a hell of a lot easier.

Here are some great resources:
http://www.valvewizard.co.uk - Merlin is the man. His preamp book is excellent and a great source of information and ideas.
http://www.ax84.com - The forum is very good and has lots of knowledgeable and helpful members. The P1 theory document is a great read.
http://music-electronics-forum.com - Probably the best forum, covers lots of aspects of design and building.

Unless you're particularly brave I'd start out with a kit. A good one will come with instructions and a building guide which will be useful as it's not obvious how some things are best done and in what order they should be done in. I do scratch builds using blank chassis' and the hardest part is the layout. Having this part done for you in worth its weight in gold as bad layout will be a self oscillating mess that is a nightmare to debug. What sort of thing do you want to build?

I'm thinking about the Ax84 P1 project. There's a place here that sells the kit for a reasonably fair price. But as i like to read and study a lot before getting my hand on things, i won't start anything until next year.

The P1 is a good start and there will be plenty support if you get into difficulties.

output buffer board populated

Test fit the boards last night. I'm going to wire this up today.
This is just the power supply and output buffer. I still need to decide what preamp to use. I'm currently leaning towards the bogner snorkeler.