The JCM800 project - Building a JCM800 from scratch!

Start. I started working on the chassis today. I took a sheet of zinc and drew the lay-out on it. The lay-out will be cut and bent as soon as I have time for it. The reason i chose to make the chassis form a sheet of zinc is simple, it happened to lie around. I does need a little polishing =)

You can see the pencil lines along which I am going to cut and bend.

I bought a little soldering station for this project. It was quite cheap but it is good enough to do the job (after a little fixing). The advantages of a station over a normal soldering iron is the temperature control and the iron holder. With a station I can put away the iron for a while without having to worry about the iron getting too hot.

isn't it ugly?

Parts! Most of the parts have arrived. I was going to wait with the orders until I would have the chassis ready but I got a little impatient. This is what (nearly) complete amplifier looks like when you spread it out on the table. The only things I still need are the output transformer (OT) and the choke.

Doesn't look like that much, does it?

Look how big the power transformer (PT) is! And how small the turrets for the circuit board are!

The thing weights more than 4 kg!

PTP. The circuit board will be soldered 'point to point' (PTP) using a turret board. For the turret board I drew a lay-out using ConceptDraw. The size of the turret board will be 310x80x4 (mm), which gave a little trouble with printing. A sheet of A4 paper is 210x297 (mm) which is just a little bit to short for the lay-out. I first tried to print it on two sheets but the margins of the printer mess (f*#^k) up the lay-out. But i found a solution to that aswell. I glued two sheets of paper together and told the printer I was feeding it a sheet of 210x5600 (mm).

The lay-out was taped to the PTP board, which was cut at the proper length. The other bit will be used in the future for the effects loop if it is big enough.
*Oops*, I made a little mistake in the lay-out, I drew one hole too much. Luckily I found it in time! Check, double check, triple check (by the way, it is fixed in the turret board lay-out).

The lay-out still looking nice.

I wanted to use a drill press stand and a regular battery powered drill but the stands looked to weak and it seemed more acurate the drill them by hand using a good centerpunch.

The lay-out looking a bit torn ;) The torn paper aren't drilling mistaskes.

Then I cleaned the holes and the result was looking realy nice!

Looking better than the lay-out

Turret time! Before I could nail the turrets in the board I had to make a tool. You can also buy ready made tools, but it is cheaper to make them yourself. I drilled a hole in a bolt and used a big centerpunch as tools. The result looks okay, but the turrets do not line up 100%. On the other hand, no one is going to look inside once it is finished...

Ready to solder!

Soldering the board was quite easy and it went really fast. I quess it is true that time flies when you're having fun ;). I only soldered the components to the board so I still have to make the connections between the different parts. But I need to know the lenghts of the wires so I am still waiting for the chassis...

It's easier than it looks

Saturday I will start with the chassis. So I prepared another lay-out for the holes in the chassis, using conceptdraw again. Front, back and top.

Another parcel has arrived! My output transformer and choke arrived today. The OT is the single most expensive part for this amplifier. But it should be worth it, as it is a Mercury Magnetics. All of the amps signal flows through the OT so i didn't want cut down on it.

Also very heavy.

Wasting paper I printed the lay-outs for the chassis real size and as a scale model. I found out that i made some little mistakes in the original lay-out, suchs as forgetting to turn the OT by 90° (I did turn the holes so they are off a couple of milimeters) and forgetting the speaker outputs. All in all, I am glad I wasted some more paper for this.

This is what a miniature amp will look like
The pen lines are the speaker outputs i forgot and the dashed lines are for the future effects loop.

First problems. When building an amp from scratch you are certainly going to run into some 'problems'. I found another one today. When I was test fitting the bolts I found out that the heads of the bolts would not fit onto the tube sockets. Easy fixed with a file, though.

Circular hole (as I bought them) on the left and an oval hole on the right

The chassis is here! I still have to drill the holes, though. The corner pieces still need to be installed also. After they are installed I am going to use the printed lay-outs to center the holes. The small holes can be drilled in the normal way, but the bigger holes can give some problems. First of all I do not have drilles that big and it is quite hard to drill holes that big in sheet metal. To make the big holes I am probably going to drill a lot of small holes in a circle and then file them to one big hole (sounds like a lot of work)...

Still needs some polishing...

Waiting to be drilled!

Because the chassis is only 1 mm thick, it is probably not strong enough to just fold it. So I installed some corner pieces.

The chassis is strong enough now.

The drilling molds are layed out!

Drilling time. With the chassis ready it was drilling time! I started around 10 o'clock in the morning and finished at 10 in evening, only taking breaks for lunch and supper. I started with the smaller, thus easier holes (2-4 mm). Then I went on to the 5 to 8 mm holes. First I tried to drill them in one go but that didn't work so well. The drill was eating (read: devouring) batteries and jammed all the time this way. I had to start with a hole of 3 mm and then drill that one up to 5 (and up to 8). And this was the easy part…
Next were the 14 and 17 mm holes. With a battery drill only fitting drills as big as 10 mm, I knew that that was going to be a problem from the start. I had to drill several holes of 3 mm in a circle and than drill them up to 5 mm, so a small 'death star' drops out, and file away the remaining bits. This took way to much time. And I still had to do the holes of 22.5, xxx, for the tube sockets and 35(!!!) mm, for the capacitor sockets! Luckily I found some screw hole punches which belonged to my granddad. One had a diameter of 30.5 mm which I used for the 35 mm hole, so I did not have to drill all those f#@*ing holes. All that I needed to do now was a little filing. The other one was 22.5 mm!!! That saved me a lot of work! Only have to file a little bit for the power tube sockets.

Do you think this looks like murder? Trust me, it is..!

The square holes were also a real massacre to make. Better tools, like a special drill for instance would have been nice. But it was possible. I don't think I will be doing something similar again soon, but I am glad I did it. I am very pleased with the result, especially when I polished it a bit.

5 empty batteries later, the result is looking really nice!

Test fit. With the chassis finished and a polished a little bit it was time for a test fit! I fitted all the parts onto the chassis and it worked out really nice! I only had to file two holes a very little bit to make everything fit snugly. Except for the power switch holes, which I made slightly too big.

This made it all worthwhile! It's looking like a real amp now.

After I made sure everything fits, it was time to take off most of the parts again. I'm going to install a nice looking face plate and back plate. So the parts which I have to install after the faceplate had to go.

Error hunting! I found two mistakes today. First, as you can see in the pictures above, I forgot to drill the holes to secure the amp to the cabinet. And when I wanted to start soldering I found out that I did not have the proper wires. So instead of soldering I started error hunting. This is what I found:

Forgetting to drill holes.

Not having ordered the proper wires.

Biggest mistake of all: I soldered a wrong capacitor to the PTP board! Instead of a 680nF capacitor I had ordered a 680pF capacitor (1000 times less capacitance) and installed it. I always thought it was very small….

Buying too small cable guides.

Buying M4 soldering eyes, while I needed M5 eyes.

cutting two bolts a few millimeters to short, because I forgot the fact that I was also going to install a faceplate.

All in all, today wasn't such a great day...

A fresh start on a new day. New holes drilled, proper wires bought and the right capacitor ordered!
It was time to solder the parts inside the amp. I made a start but I ran out of solder... I am not so pleased with the heating wires (the thick red/black twisted ones). Maybe I am going to do them again, for the fourth(!!!) time. Only the pre amp tubes, because the power amp tubes are fine.

Heating wires, again...I have done the heater wires again (for the power tubes aswell) . This time it did work out nice. I bought new wires this time, which were a bit smaller and a bit stiffer, which made working with them a little bit better

It is finally starting to look like it could actually work!

I've also done the wirings on the PTP board, except for the capacitor which I have to switch and the wires from the transformers.
I've 'borrowed' the idea of the ground wire (the copper wire) from what I saw on Joe Popp's weblog. This way I only have one wire from the intire PTP board and pots running to the chassis. Which makes it look very tidy inside.

All wired up.

The power tube sockets are as good as finished, but there is not much more I can do untill i have to PTP board ready again.

Effects loop I received a beautiful parallel effects wiring diagram! It is said to be the only trully quite effects loop around. I can not give any more details as I prommised to keep it a secret. But I can tell you it is looking really good!
The downside of installing an effects loop is that I had to drill some more holes. This time i also had to make sure I did not damage any of the already installed parts inside. I prepared very well and it turned out nice. I have to add an extra tube and some in/out puts and pots.

A couple of extra holes for the parallel FX loop.

I also ordered the face plates today. Hopefully my parcels for the FX loop arive soon so i can start working on the amp again. Once the FX loop is finished and the plates are ready I can complete the amp!

PTP board fixed & FX loop I switched the capacitor on the PTP board for the correct one. And I also made the effects loop. It is looking great but I promised not to share image of it. While I was making the second turretboard I took some pictures for a tutorial on turretboard making ;)

Looking much better!

Face plates After two weeks of waiting I finally continued working. The Face plates I ordered (that's what I was waiting for) turned out to be way to expensive. So I had to conjure up a way to make them myself.
I bought a sheet of very thin aluminium at the local hardware store and cut it into the right size. I had to make sure that I had everything perfectly aligned. As you can see I failed horribly the first time.

The input holes are wrong and the plate is too long on one end.

Luckily the sheet was big enough to make four plates. The second try was nearly perfect. When I was sure that everything did fit I started polishing. As soon as the polishing was finished I started to put on the decals I prepared the day before.

The faceplates cut and drilled

Faceplates polished

The decals were printed on special decal paper. To make those decals proved to be a real struggle. I bought special paper at a local scale model store. I asked for inkjet paper but I got laser printer paper. The ink didn't attach to the paper at all and formed little droplets. So I went back to the store and told what happened. The store didn't have any inkjet paper! But the guy turned out to be really kind and offered to print my decals on his laser printer.

These are all the decals
instruction on how to make decals can be found here (.pdf, dutch)

After the decals were in place I used a hair drier to make sure there was absolutely no water underneath the decals and left them another while.

I used clear varnish for cars to make sure the decals won't come off. It looks like the decals did react a bit with the varnish but as long as you don't come close it looks okay.

Looking really nice!

Finishing With the face plates in place I could finaly start to finish the amp! The transformers connected!

Transformers connected for the first time.

In my enthousiasm I made a BIG mistake. I soldered the turret board to the wrong tube sockets. This meant most of the wires were cut too short to make it to the right socket. It was quite easy to fix as I had enough wire left to make it again.

the socket to the left should have been connected...

That fixed it was time to connect it properly. This time I tried to stay focused.

Sockets connected only the pots and some other wires left!

Once the wires on one wide were connected, I connected the other side. The inputs and the potmeters.

Everything connected!

Firing her up Everything connected, everything cleaned, everything double checked. Time to see if it works. I don't have a speaker cabinet (yet) so I used the speakers from my valvestate combo.

My "beautiful" test set up =)

The first test would be without a guitar connected just listing to what would happen. Turned on the power. Nothing...
Inserted the mains fuse. All tubes started to glow!
Inserted the H.T. fuse. Hit the stand-by. Nothing, no sound...
Turned the pre-amp volume up, no sound...
Turned the master volume up, nothing...
Cranked both volumes! a very soft hum.
Lowered the master to eight, nothing.
I thought the amp did not work but I had to try with a guitar... Connected a guitar and fliped the stand-by switch again. No sound, cranked the pre-amp and turen master to 1. MUSIC!!!

This amp is so quiet I first thought it didn't work! No pop when you hit a switch, no hum!

The effects loop also works realy fine! The only downside is that I cannot switch from effects loop to by-pass with the amp on. It is not a big problem because the effects loop is really quiet.

I haven't done a proper test (nor have I played on it properly) because I still have to adjust the bias. I've ordered a bias probe and as soon as I get it I can start playing!

Bias I've managed to drop the bakelite tube feet and it broke into eight pieces. I've spent the whole afternoon glueing the pieces together again. I couldn't find a couple of bits but the probe can be used.

Bias adjusting in progress

I've biased the tubes at 70%. The plate voltage is 413V and the maximum power of the tube is 25W. So 25W*70% = 17.5W. 17.5W/413V = 0,042A. And because the bias probe uses an 1 ohm resistor I had to set the tubes to 0.042V.

Playing with the bias properly set it was time to put the amp to the test (and to take some nice pictures)! I've played for about 6 hours in total now so the transformers still have to break in, which happens after about 20 hours.

Wow!
You can really tell the different brands of tube by the way they glow.

Making the cabinet For the cabinet I used MDF (medium density fibreboard). It's cheap and strong. Using a circular saw the mdf was cut into the right sizes.

Test fit

The test fit was succesfull so I screwed everything together. That was the easy part. The hard part was making the nice round corners. I've used a plane, a file and a whole day of work. I am quite satisfied with the result!

Nice corners

On bottom of the inside I've used some kind of special aluminium paint. This is suppost to act as the bottom of the faraday cage (in conjunction with the chassis). Reducing distortions form outside. This is probably the least healthy paint on the planet, as it dries while you like at it. When the paint is fully dry I will paint everything black on the inside.

The worst paint job ever =P

The front and the pack of the cabinet are ready. Just another test fit to make sure.

The front

and the back

The cabinet fully tolexed. I've used Bison Tix to glue the tolex to the wood. I've also installed the corner pieces and the handle.

Looking good

I've used brass screws. I think it looks nice.

FINISHED! Well... Not entirely. I still have to think of some kind of logo.

Finally finished



	Introduction

	I've owned a Marshall Valvestate VS265r for a couple of years. I like its versatility but I felt I was missing something sound wise. Time for a sound upgrade! I liked the sound of a JCM800. Maybe I was going to buy myself a 50 watt channel switching combo. But what's the fun that? I started reading and searching on internet and I found a company that makes amplifier kits. Maybe it would be a good idea to buy a kit? Searching the web for kits I stumbled upon a great website about a ceratin brand of kits. Joe Popp has made a really good website about building, upgrading and perfecting those kits. I was about to order such a kit but than I figured it would be even a bigger challenge to build an amp from scratch! When building an amp from scratch you can do anything you like. As soon as i started reading I didn't want to build a combo anymore, I wanted a head! And I read that the channel switching models work a bit different from the single channel models, which sounds best, so I will be building a single channel model. But to add some diversity I will be installing a parallel effects loop, with an FX MIX pot. There are plenty schemes and detailed information about mods and more on the internet. I downloaded some schemes compared them, looked at more schemes, compared them as well and than I added some mods to my own scheme. But I didn't find a proper effects loop sheme, so that will have to come later. I started reading books about soldering, electronics and amplifiers. And most important, I started making a list of all the parts I should buy and what they would cost. I soon discovered one thing: You shouldn't build your own amplifier because it is cheaper than buying one! A second hand JCM800 costs almost the same as building your own and than I am not even speaking of the hours of work I have (yet to) put into this project! I am going to keep you updated about my progress! ~~And I want to apologize for the crappy lay out... It's been a while since I last used HTML~~ - It is looking a little better now.
	Design
	This is what the finished amplifier should look like (hopefully even better): Hopefully mine will look a little less abused =P I made a lay-out, with measures, for the chassis and the electrical scheme. I am still working on the lay-out for the cabinet... Specifications and modifications: Sizes as close as possible to the original. A silver (probably aluminium) faceplate. Silver knobs. Golden or brass (colour) logo (or maybe bronze). (Hopefully) better sound at low volumes. By removing one treble peaking circuit and increasing the gain a little bit. (see the scheme for more details) Mercury Magnetics output transformer and choke Hammond Power transformer And a true by-passable effects loop.

	The Build
	Start. I started working on the chassis today. I took a sheet of zinc and drew the lay-out on it. The lay-out will be cut and bent as soon as I have time for it. The reason i chose to make the chassis form a sheet of zinc is simple, it happened to lie around. I does need a little polishing =) You can see the pencil lines along which I am going to cut and bend. I bought a little soldering station for this project. It was quite cheap but it is good enough to do the job (after a little fixing). The advantages of a station over a normal soldering iron is the temperature control and the iron holder. With a station I can put away the iron for a while without having to worry about the iron getting too hot. isn't it ugly? Parts! Most of the parts have arrived. I was going to wait with the orders until I would have the chassis ready but I got a little impatient. This is what (nearly) complete amplifier looks like when you spread it out on the table. The only things I still need are the output transformer (OT) and the choke. Doesn't look like that much, does it? Look how big the power transformer (PT) is! And how small the turrets for the circuit board are! The thing weights more than 4 kg! PTP. The circuit board will be soldered 'point to point' (PTP) using a turret board. For the turret board I drew a lay-out using ConceptDraw. The size of the turret board will be 310x80x4 (mm), which gave a little trouble with printing. A sheet of A4 paper is 210x297 (mm) which is just a little bit to short for the lay-out. I first tried to print it on two sheets but the margins of the printer mess (f#^k) up the lay-out. But i found a solution to that aswell. I glued two sheets of paper together and told the printer I was feeding it a sheet of 210x5600 (mm). The lay-out was taped to the PTP board, which was cut at the proper length. The other bit will be used in the future for the effects loop if it is big enough. Oops, I made a little mistake in the lay-out, I drew one hole too much. Luckily I found it in time! Check, double check, triple check (by the way, it is fixed in the turret board lay-out). The lay-out still looking nice. I wanted to use a drill press stand and a regular battery powered drill but the stands looked to weak and it seemed more acurate the drill them by hand using a good centerpunch. The lay-out looking a bit torn ;) The torn paper aren't drilling mistaskes. Then I cleaned the holes and the result was looking realy nice! Looking better than the lay-out Turret time!* Before I could nail the turrets in the board I had to make a tool. You can also buy ready made tools, but it is cheaper to make them yourself. I drilled a hole in a bolt and used a big centerpunch as tools. The result looks okay, but the turrets do not line up 100%. On the other hand, no one is going to look inside once it is finished... Ready to solder! Soldering the board was quite easy and it went really fast. I quess it is true that time flies when you're having fun ;). I only soldered the components to the board so I still have to make the connections between the different parts. But I need to know the lenghts of the wires so I am still waiting for the chassis... It's easier than it looks Saturday I will start with the chassis. So I prepared another lay-out for the holes in the chassis, using conceptdraw again. Front, back and top. Another parcel has arrived! My output transformer and choke arrived today. The OT is the single most expensive part for this amplifier. But it should be worth it, as it is a Mercury Magnetics. All of the amps signal flows through the OT so i didn't want cut down on it. Also very heavy. Wasting paper I printed the lay-outs for the chassis real size and as a scale model. I found out that i made some little mistakes in the original lay-out, suchs as forgetting to turn the OT by 90° (I did turn the holes so they are off a couple of milimeters) and forgetting the speaker outputs. All in all, I am glad I wasted some more paper for this. This is what a miniature amp will look like The pen lines are the speaker outputs i forgot and the dashed lines are for the future effects loop. First problems. When building an amp from scratch you are certainly going to run into some 'problems'. I found another one today. When I was test fitting the bolts I found out that the heads of the bolts would not fit onto the tube sockets. Easy fixed with a file, though. Circular hole (as I bought them) on the left and an oval hole on the right The chassis is here! I still have to drill the holes, though. The corner pieces still need to be installed also. After they are installed I am going to use the printed lay-outs to center the holes. The small holes can be drilled in the normal way, but the bigger holes can give some problems. First of all I do not have drilles that big and it is quite hard to drill holes that big in sheet metal. To make the big holes I am probably going to drill a lot of small holes in a circle and then file them to one big hole (sounds like a lot of work)... Still needs some polishing... Waiting to be drilled! Because the chassis is only 1 mm thick, it is probably not strong enough to just fold it. So I installed some corner pieces. The chassis is strong enough now. The drilling molds are layed out! Drilling time. With the chassis ready it was drilling time! I started around 10 o'clock in the morning and finished at 10 in evening, only taking breaks for lunch and supper. I started with the smaller, thus easier holes (2-4 mm). Then I went on to the 5 to 8 mm holes. First I tried to drill them in one go but that didn't work so well. The drill was eating (read: devouring) batteries and jammed all the time this way. I had to start with a hole of 3 mm and then drill that one up to 5 (and up to 8). And this was the easy part… Next were the 14 and 17 mm holes. With a battery drill only fitting drills as big as 10 mm, I knew that that was going to be a problem from the start. I had to drill several holes of 3 mm in a circle and than drill them up to 5 mm, so a small 'death star' drops out, and file away the remaining bits. This took way to much time. And I still had to do the holes of 22.5, xxx, for the tube sockets and 35(!!!) mm, for the capacitor sockets! Luckily I found some screw hole punches which belonged to my granddad. One had a diameter of 30.5 mm which I used for the 35 mm hole, so I did not have to drill all those f#@ing holes. All that I needed to do now was a little filing. The other one was 22.5 mm!!! That saved me a lot of work! Only have to file a little bit for the power tube sockets. Do you think this looks like murder? Trust me, it is..! The square holes were also a real massacre to make. Better tools, like a special drill for instance would have been nice. But it was possible. I don't think I will be doing something similar again soon, but I am glad I did it. I am very pleased with the result, especially when I polished it a bit. 5 empty batteries later, the result is looking really nice! Test fit.* With the chassis finished and a polished a little bit it was time for a test fit! I fitted all the parts onto the chassis and it worked out really nice! I only had to file two holes a very little bit to make everything fit snugly. Except for the power switch holes, which I made slightly too big. This made it all worthwhile! It's looking like a real amp now. After I made sure everything fits, it was time to take off most of the parts again. I'm going to install a nice looking face plate and back plate. So the parts which I have to install after the faceplate had to go. Error hunting! I found two mistakes today. First, as you can see in the pictures above, I forgot to drill the holes to secure the amp to the cabinet. And when I wanted to start soldering I found out that I did not have the proper wires. So instead of soldering I started error hunting. This is what I found: Forgetting to drill holes. Not having ordered the proper wires. Biggest mistake of all: I soldered a wrong capacitor to the PTP board! Instead of a 680nF capacitor I had ordered a 680pF capacitor (1000 times less capacitance) and installed it. I always thought it was very small…. Buying too small cable guides. Buying M4 soldering eyes, while I needed M5 eyes. cutting two bolts a few millimeters to short, because I forgot the fact that I was also going to install a faceplate. All in all, today wasn't such a great day... A fresh start on a new day. New holes drilled, proper wires bought and the right capacitor ordered! It was time to solder the parts inside the amp. I made a start but I ran out of solder... I am not so pleased with the heating wires (the thick red/black twisted ones). Maybe I am going to do them again, for the fourth(!!!) time. Only the pre amp tubes, because the power amp tubes are fine. Heating wires, again...I have done the heater wires again (for the power tubes aswell) . This time it did work out nice. I bought new wires this time, which were a bit smaller and a bit stiffer, which made working with them a little bit better It is finally starting to look like it could actually work! I've also done the wirings on the PTP board, except for the capacitor which I have to switch and the wires from the transformers. I've 'borrowed' the idea of the ground wire (the copper wire) from what I saw on Joe Popp's weblog. This way I only have one wire from the intire PTP board and pots running to the chassis. Which makes it look very tidy inside. All wired up. The power tube sockets are as good as finished, but there is not much more I can do untill i have to PTP board ready again. Effects loop I received a beautiful parallel effects wiring diagram! It is said to be the only trully quite effects loop around. I can not give any more details as I prommised to keep it a secret. But I can tell you it is looking really good! The downside of installing an effects loop is that I had to drill some more holes. This time i also had to make sure I did not damage any of the already installed parts inside. I prepared very well and it turned out nice. I have to add an extra tube and some in/out puts and pots. A couple of extra holes for the parallel FX loop. I also ordered the face plates today. Hopefully my parcels for the FX loop arive soon so i can start working on the amp again. Once the FX loop is finished and the plates are ready I can complete the amp! PTP board fixed & FX loop I switched the capacitor on the PTP board for the correct one. And I also made the effects loop. It is looking great but I promised not to share image of it. While I was making the second turretboard I took some pictures for a tutorial on turretboard making ;) Looking much better! Face plates After two weeks of waiting I finally continued working. The Face plates I ordered (that's what I was waiting for) turned out to be way to expensive. So I had to conjure up a way to make them myself. I bought a sheet of very thin aluminium at the local hardware store and cut it into the right size. I had to make sure that I had everything perfectly aligned. As you can see I failed horribly the first time. The input holes are wrong and the plate is too long on one end. Luckily the sheet was big enough to make four plates. The second try was nearly perfect. When I was sure that everything did fit I started polishing. As soon as the polishing was finished I started to put on the decals I prepared the day before. The faceplates cut and drilled Faceplates polished The decals were printed on special decal paper. To make those decals proved to be a real struggle. I bought special paper at a local scale model store. I asked for inkjet paper but I got laser printer paper. The ink didn't attach to the paper at all and formed little droplets. So I went back to the store and told what happened. The store didn't have any inkjet paper! But the guy turned out to be really kind and offered to print my decals on his laser printer. These are all the decals instruction on how to make decals can be found here (.pdf, dutch) After the decals were in place I used a hair drier to make sure there was absolutely no water underneath the decals and left them another while. I used clear varnish for cars to make sure the decals won't come off. It looks like the decals did react a bit with the varnish but as long as you don't come close it looks okay. Looking really nice! Finishing With the face plates in place I could finaly start to finish the amp! The transformers connected! Transformers connected for the first time. In my enthousiasm I made a BIG mistake. I soldered the turret board to the wrong tube sockets. This meant most of the wires were cut too short to make it to the right socket. It was quite easy to fix as I had enough wire left to make it again. the socket to the left should have been connected... That fixed it was time to connect it properly. This time I tried to stay focused. Sockets connected only the pots and some other wires left! Once the wires on one wide were connected, I connected the other side. The inputs and the potmeters. Everything connected! Firing her up Everything connected, everything cleaned, everything double checked. Time to see if it works. I don't have a speaker cabinet (yet) so I used the speakers from my valvestate combo. My "beautiful" test set up =) The first test would be without a guitar connected just listing to what would happen. Turned on the power. Nothing... Inserted the mains fuse. All tubes started to glow! Inserted the H.T. fuse. Hit the stand-by. Nothing, no sound... Turned the pre-amp volume up, no sound... Turned the master volume up, nothing... Cranked both volumes! a very soft hum. Lowered the master to eight, nothing. I thought the amp did not work but I had to try with a guitar... Connected a guitar and fliped the stand-by switch again. No sound, cranked the pre-amp and turen master to 1. MUSIC!!! This amp is so quiet I first thought it didn't work! No pop when you hit a switch, no hum! The effects loop also works realy fine! The only downside is that I cannot switch from effects loop to by-pass with the amp on. It is not a big problem because the effects loop is really quiet. I haven't done a proper test (nor have I played on it properly) because I still have to adjust the bias. I've ordered a bias probe and as soon as I get it I can start playing! Bias I've managed to drop the bakelite tube feet and it broke into eight pieces. I've spent the whole afternoon glueing the pieces together again. I couldn't find a couple of bits but the probe can be used. Bias adjusting in progress I've biased the tubes at 70%. The plate voltage is 413V and the maximum power of the tube is 25W. So 25W70% = 17.5W. 17.5W/413V = 0,042A. And because the bias probe uses an 1 ohm resistor I had to set the tubes to 0.042V. Playing* with the bias properly set it was time to put the amp to the test (and to take some nice pictures)! I've played for about 6 hours in total now so the transformers still have to break in, which happens after about 20 hours. Wow! You can really tell the different brands of tube by the way they glow. Making the cabinet For the cabinet I used MDF (medium density fibreboard). It's cheap and strong. Using a circular saw the mdf was cut into the right sizes. Test fit The test fit was succesfull so I screwed everything together. That was the easy part. The hard part was making the nice round corners. I've used a plane, a file and a whole day of work. I am quite satisfied with the result! Nice corners On bottom of the inside I've used some kind of special aluminium paint. This is suppost to act as the bottom of the faraday cage (in conjunction with the chassis). Reducing distortions form outside. This is probably the least healthy paint on the planet, as it dries while you like at it. When the paint is fully dry I will paint everything black on the inside. The worst paint job ever =P The front and the pack of the cabinet are ready. Just another test fit to make sure. The front and the back The cabinet fully tolexed. I've used Bison Tix to glue the tolex to the wood. I've also installed the corner pieces and the handle. Looking good I've used brass screws. I think it looks nice. FINISHED! Well... Not entirely. I still have to think of some kind of logo. Finally finished
	Speaker cabinet
	Not Finished... Now I've got the perfect amp, I noticed that the 'borrowed' speakers of my valvestate aren't that perfect. Time to build a speaker cabinet! With this JCM I did prove that the bass respons that is lacking in the valvestate is not a problem of the speakers. Yet the speakers don't sound that great... The cabinet should be the same width as the amp, for the height and depth I used the adviced distances. front back side the spray painted baffle FINISHED AGAIN! Well... Still not entirely. I still have to conjure up some kind of logo for the amp... I made a white piping on the speaker cabinet, so I also had to add one to the amp. Making the amp look a lot better, me thinks... Endlich... Which is nicer, the front or the back? MUSIC!

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