Getting a head of myself - Marshall 2204 JCM800 inspired build

[ChopSauce]

If your iron is not powerfull enough it may not sustain this temperature with such an heat sink as a turret. 20-30 watts is commonly used for PCBs but not enough for turrets. This is the reason for I prefer eyelets.

[kuDo]

If your iron is not powerfull enough it may not sustain this temperature with such an heat sink as a turret. 20-30 watts is commonly used for PCBs but not enough for turrets. This is the reason for I prefer eyelets.

I use a 80 watts soldering station which is temperature adjustable. Maybe I need another tippoint for these situations. I am now using a pointy shaped one.

[Reeltarded]

aha stop using celsius and get a good fahrenheit iron

[Reeltarded]

but seriously, do take a look at the tip and make sure it is seated and that it is super clean in the connection to the iron..

[kuDo]

Good point, I will take a look at it!

[ChopSauce]

Pointy shape?



Something with a wider surface of contact should help.

[kuDo]

Yess, something resembling the soldering iron the guy in this video has at 3:46.

[ChopSauce]

I'm certainly not qualified to comment on other people's soldering techniques - but ...

Yet it seems unavoidable to heat the parts to solder with the melted metal bath in the final, I prefer to have the widest contact between the iron and the part, for I hate cold solder and want to minimize this risk.
(plus as a metalworker I've been told to manage to concentrate heat as much as possible to minimize heat spread and warpage, when welding)

He seems to achieve this pretty well with a pointy tip. I'll try it.

[kuDo]

Time for another update.

I have been busy building. Soldering away, one component at a time.
Slowly but steady I proceed to my goal of creating my own amp, that will hopefully work one day.

I have been shoping for some new wires. I was planning to use use one thickness of wire, but I found out that wasn’t the way to go. The wire I was using for the heaters, and was planning to use for the rest of the amp, was much to thick. It proved to be a problem when more then one item needed to be connected to a turret.
Also for the first stages of the amp I used shielded cable, but apparently I ordered the wrong wire. The shielded wire I first ordered, had a really thiny core wire. So fragile that I was scared that It would snap under it’s own weight and flex.

In the end I ordered thinner wires for the rest of the amp, and it has proven to be a great decision. For the signal wire I now went ahead and ordered a version with a thicker core wire. All is now well.

[kuDo]

This weekend I heard the first sounds comming from the amp I have build. It's great!

It just worked perfect right from the start. Somehow I had the idea that this wouldn't be an easy ride. But it turned out just right.
As my first test of the heaters a couple of weeks ago didn't go as planned, I was under the impression that this would also contain a mistake or two.

It sounds great and I am really curious to know what this would sound like with some pedals in front of it like a tube screamer. I think it will be perfect for that kind of thing.

Only thing I noticed is that it is hissing quit a lot. No heater hum, just a constant hiss. No problem when you are playing but it is there when you stop.
I don't know how bad it is with the real JCM, because I never played one in real life.

I am really happy so far. I will post some more when I adjust it, or start to work on the enclosure.

Here is a little clip I recorded with my Ipad. The sound is real quit, but it has got to do for now.
I recorded a little loop with my "ditto looper" which I ran in the effect loop I added to this amp. The effectsloop stage contains a 12au7, it works great.
Than, I noodled a little on top of it

[xtian]

Nice job! I can't tell a thing from your video, sorry.

But about the hiss: I had a 1983 JCM 800 2203, and I now have a 2204 that I built last month. They both sound the same, in terms of hiss. If you plug into the Low input and turn the gain all the way up, there is no hiss at all, until you turn the Master volume up really high. But if you plug into the High input and turn the gain all the way up, you can certainly hear some hiss when you crack open the Master volume. But no worries, because that's a LOT of gain.

[kuDo]

Thank you!

The video was to give a slight impression of the sound.

If the master volume is down, in my case , there is no hiss.
When no instrument is connected and you turn up the master volume half way. There is a slight hum, which is not so bad.
But then, if you open up the pre volume. Then the hiss comes.

So it behaves like you describe.

Also, I added a picture of the chassis in the wooden enclosure. I couldn’t resist. Really pleasing!

[kuDo]

This is an example of the hiss.

The first 2 volume swells are of the master volume from 0 to 10 with the pre amp volume at 0.

The latter swells are with the master volume at 1/3. The sweeps are made with the pre amp volume from 0 to 10.

Treble is set all the way open as is the precence.

[kuDo]

I think this hiss is down to the grid stopper resistor (68k) of the first stage.
I will take a look at it soon.

[ChopSauce]

... I added a picture of the chassis in the wooden enclosure. I couldn’t resist. Really pleasing!

Simple, yet efficient...

"Tube Town inside"?