DIY Valve Guitar Amp Head

[Ik7]

Have you guys ever tried the Russian equivalent of the ecc83/12ax7? Or even their 6V6 or EL84 tubes? They can handle much higher plate voltages and sound incredible. I use them in my builds, the 12ax7 is easier to wire up too as pin 4 and 5 are heaters, and pin 9 is used on an internal shield.

The other good thing is they are cheap too, I paid £12 for 4 12ax7s and two EL84's.

[DrNomis_44]

Have you guys ever tried the Russian equivalent of the ecc83/12ax7? Or even their 6V6 or EL84 tubes? They can handle much higher plate voltages and sound incredible. I use them in my builds, the 12ax7 is easier to wire up too as pin 4 and 5 are heaters, and pin 9 is used on an internal shield.

The other good thing is they are cheap too, I paid £12 for 4 12ax7s and two EL84's.

To be honest, I didn't even know that there was a Russian equivalent of the ECC83/12AX7, or the 6V6 and EL84, but I'm assuming that their electrical characteristics should be reasonably similar, if not the same, most of the valves available today are made either in China (Shugang), Yugoslavia, or in Russia (Sovtek), during the 50's and 60's, because Russia was a Communist nation, it was effectively shut-out of the Solid-State revolution happening in America, so it tended to rely quite heavily on valve technology so the majority of valve manufacturing plants tended to be in European and Asian parts of the world, although Britain and America had valve manufacturing plants too.

[Marcel]

Philips also had tube manufacturing in many place with the biggest in the Netherlands and Germany, They also had two plants in Australia being one in Sydney and another in Melbourne... At one time there was also four TV & radiogram building factories within walking distance of the Melbourne tube factory...

Alas, all are long gone...

[Marcel]

What too much coffee does to an amp builder..... lol

https://www.youtube.com/watch?v=9r46NASb-3w

[DrNomis_44]

Yep, too much of that stuff will do it....lol.

[DrNomis_44]

Update:


I went to my local Officeworks shop today to buy a few things I needed, while I was there I also bought a 128 page book of 5mm graph paper, there's a good reason why I bought it, it's for designing my own Turret Board layouts, I've never tried designing a turret Board layout so I thought that I would have a go at it as part of the build-process for the amp, I've already got a set of layouts in PDF form but there's a slight problem, the Turret Board insulation material that I'm going to order from Evatco is smaller in size compared to the pdf layouts, so I need to do some re-designing....no drama though.




Usually on a Turret Board, the Turrets are placed about 10mm apart, using graph paper to design a layout will help to keep the Turrets in a straight line.

[DrNomis_44]

It's a bit of a quiet and rainy day at home today, so I thought that it would be a good excuse to do some work on getting things organized with regards to the parts and bits and pieces needed to complete my Sloclone 50 amp head rebuild, to start off, I'm in the process of evaluating how many sheets of blank fibreglass turret board, and turrets I'll need to order from Evatco to make the turret boards for the amp, Evatco stock two different thickness of blank fibreglass turret boards, a 2mm thick board and a 3mm thick board, you can order them as a 300mm by 60mm sheet, or a 300mm by 80mm sheet, I'm going with the 2mm by 300mm by 80mm sheets because they are closest in dimension to the specifications in the pdf layouts I'm working with, the only issue is that the length is a bit short but I'm going to get round that by building the majority of the preamp circuitry on one 300mm by 80mm board, and then build the phase-splitter circuitry on a shorter board, hence the reason why I need to work out how many 2mm by 300mm by 80mm sheets I need to order, also, I decided to go with the 2mm sheets because that will make it easier for me to cut them to length.

The reasons why I chose to use turret boards rather than etch a PCB is as follows:

1, I'm currently not set up to etch my own PCBs.

2, I've never tried making a turret board before, and this project seemed like as good an excuse as any.

3, A turret board is much easier to service when it comes to replacing faulty components, you simply de-solder them from their turrets (have you ever noticed how frustrating it can be to replace a faulty component on an etched PCB?, you have to completely remove it from the amp chassis to replace the part, then re-install it to perform tests on the amp).

What I've done so far is to cut a couple of pieces of cardboard roughly to 300mm by 80mm and a couple more to 150mm by 80mm (these will represent the phase-splitter and power supply boards), and then I'm going to use the pieces of cardboard to do a test-fit evaluation to see how it's all going to work out with regards to turret board positioning in the amp chassis, might see if I can take a pic or two so you can see how they are going to be arranged.


Here's a pic of how the turret boards are going to be roughly arranged, although I may need to tweak it a bit later on, this does seem to work though:




It looks like I'll need to order a minimum of two 2mm by 300mm by 80mm blank fibreglass turret boards, but I'll increase the quantity to four, that way if I somehow make a mistake on one of the boards (lets face it, in the real world nothing ever goes exactly to plan according to Murphy's Law), I can simply cut a new piece and start again, hopefully I'll get it right the first time.


In the above pic the piece of cardboard labeled "Preamp" represents the turret board with the majority of the preamp circuit on it, likewise, the piece of cardboard labeled "Phase Splitter" represents the phase-splitter turret board, and the piece of cardboard labeled "Power Supply" represents the power supply turret board.

[Marcel]

The only spanner flying through the air with your design method Doc is the spacing of the turrets on the boards from Evacto. If you have included that on your cardboard cut outs then all is sweet, if not then Murphy is still possibly in the mix...

[DrNomis_44]

The only spanner flying through the air with your design method Doc is the spacing of the turrets on the boards from Evacto. If you have included that on your cardboard cut outs then all is sweet, if not then Murphy is still possibly in the mix...

Good point, I was assuming that the turrets are spaced 3/8 inch, or 10mm apart from each other (I think that's the standard spacing), the graph paper I'm using to create the layouts is 5mm square, so, if I space the turrets out every two 5mm squares, then it should be fine, hopefully Murphy doesn't throw a spanner in the works.


One thing though, when we make assumptions we leave ourselves wide open to mistakes being made.

[DrNomis_44]

Update:

Rightio, time for an update.....


Just been working on making up a layout for one of the Turret boards for the amp I'm in the process of building, anyway, as it turns out a 300mm by 80mm piece of F4 fibreglass board is going to be too small to accommodate most of the preamp circuitry, Evatco sells sheets of F4 fibreglass board material in either 300mm by 60mm, or 300mm by 80mm, in 2mm or 3mm thickness, so, rather than follow the layout I'm working from verbatim, I'm going to have to get a bit creative, and I think I've figured out a solution, I'll need to do some experimenting to be sure though.