[JayVee]

Hi,
I was checking out some other preamps for my Soldano SLO100 project because I hear the clean is pretty weak and the crunch isn't superb either.
Now I had some troubles with designing the powersupply, never did anything like that before.
I just kept the part for the poweramp (which is incomplete on my schematic? No B1?) and wanted to add a part for the voltages to the preamp.
This is my SLO schem:
http://img244.imageshack.us/my.php?image=slo1001ex8.gif
http://img244.imageshack.us/my.php?image=slo1002mv5.gif

And here's what I tried already:
http://img216.imageshack.us/my.php?image=powersupplyxu7.jpg

As you can see I just need the voltages for the SLO poweramp and a couple of 450V taps for my preamp which I only drew once.
I also don't know what transformer specs (voltages) I need.
I have tried the search but I don't speak German, and online translaters just make a mess of things, hope you guys can give me a hand..
Excuses for the English by the way..

[Joachim]

Hi Jay,

Don't use the schematics you mentioned in your post as they are partially fairly wrong! Either you should use the schematics from the sloclone-Forum (http://sloclone.yesterdaysrevolt.com/ or my schematics, which you will find attached to this Post.

http://www.tube-town.de/ttforum/index.php?topic=3292.msg26052#msg26052

You will find all significant voltages in my schematics, however voltages may vary when using different tubes. Sound is a matter of taste, but I pretty like the SLO's crunch which is - in my humble opinion - admirable! I also remarked a mod at R7 in my schematics which gives more bity to the somewhat flabby clean sound. Also there are many pictures from my build in this thread which may help, despite the fact the tread text is in German..

Here you will find a power transformer which fit's perfectly in a SLO: http://www.shinrock.com/index.php?smt-soldano_100. Shinrock also offers a Choke and an output transformer.

You should be aware that a SLO is not a beginners project and also there are lethal voltages in tube amps. So you should be experienced in building tube amps and have good skills in electronics when building this amp.

Hope this helps.

Cheers, Joachim

[JayVee]

Hi,
thanks for the quick reply.
I know the riscs of tube amps, I've already built some smaller things before, but those were just clones, nothing hard about following an existing schematic, not at all when you've got a layout to guide you, but I don't understand enough of it yet to design my own stuff.
I've checked out your schematic and I should be able to take the 450V from between the screens and B2 supply, no?
Just adding a low valued resistor and an elco to ground while lowering the 10k R62 a little should do the job no?

[Joachim]

I'm wondering if I understand you right now. You're only building a preamp? Sure you can take the 450 Volts at the circuit point you mentioned but why do you need 450Volts in the preamp??? Or did I get it completely wrong?

[JayVee]

I'm building a complete amp, but unlike the SLO lead which I love I also hate the clean.
I wanted to add a better clean channel, and I heard one in a preamp which I just love.
So I wanted to take the clean channel from that preamp schematic and use it in the SLO.
On the preamp schematic I seem to need 450V from my powersupply..
For example, 450V PS goes through 100k or 220k resistor and to pin 1/plate of ecc83.
Too high values? Perhaps that schematic stinks aswell, no idea..

PM'd you by the way.

[Joachim]

Hmm? Well a 12AX7A is specified with a maximum plate voltage between 300 and 330 Volts (absolute value varies from manufacturer to manufacturer). So you should not exeed 330V at the plates of your preamp tubes. With a 100k plate resistor you may be somewhat above the limits.

[JayVee]

But the 220k would be ok?

[Joachim]

There is more voltage drop over the 220k so the plate voltage should come closer or at least into the specs.