Steddi, Go! - simple tube D.I.

[havnjero]

well I've done a few measurements here, with a 1957 RCA 5751.

with a straight cable, for reference:


steddi plugged in, bypassed:


steddi engaged, with 1uF


steddi engaged, with 10uF


and here is the frequency curve trace, with a cable above and steddi below, engaged, with 10 and 1 uF, separately.



I'm not seeing much effect of changing caps @C2, so I'm wondering if changing C1 would be better -- or someplace else?

 

[Tassieviking]

What are you trying to do ?
C1 and the volume pot makes a HPF at 0.2Hz so that is as low as you would ever want it.
I have no idea how to work out the HPF of C2 but usually we use a higher capacitance for a lower frequency, C2 is marked as 47uF in the build docs.

 

[havnjero]

What are you trying to do ?
C1 and the volume pot makes a HPF at 0.2Hz so that is as low as you would ever want it.
I have no idea how to work out the HPF of C2 but usually we use a higher capacitance for a lower frequency, C2 is marked as 47uF in the build docs.

same as before, I'm trying to have a hpf which is not so gradual, so as to include good things in the 50hz region.

 

[havnjero]

same as before, I'm trying to have a hpf which is not so gradual, so as to include good things in the 50hz region.

well, I got around to fiddling with info and doing a slow tone sweep, and found that looking at distortion was good fun.
I also did spl measurements with different tubes, but there was more information with the distortion charts.

I'm using Room Eq Wizard, which is easy to use and colorful. it helps one see what harmonic content looks like at different gain levels. I've been testing mostly at 100mV, which is less than a typical full output of a passive bass guitar like a P bass.

with higher gain tubes, the overall gain goes way down, and with lower gain tubes, the overall gain goes up. sometimes close to 12dbfs. which is a lot.

it sounds great, and is very musical. hard to beat a 12bh7 or clear top rca ecc82.





I find that the tube boards and right angle connectors are not ideal for lots of tube swapping, and the pcb material bends a lot, ruining the solder joint, so I have to go over the joint after changing tubes. it could help for the steddi to have a shoulder for the tube to rest on, which would be more stable in the long run. more like the firebox:

 

[havnjero]

@vigilante398, is a 25v cap in C4 ok?

 

[Tassieviking]

C4 is only at whatever voltage you supply the pedal with, since you should keep it at or below 14V DC maximum you could even use a 16V cap there very safely so I see no problem with using a 25V cap.

 

[havnjero]

C4 is only at whatever voltage you supply the pedal with, since you should keep it at or below 14V DC maximum you could even use a 16V cap there very safely so I see no problem with using a 25V cap.

ok, thats what I figured. next time I'll just send you a message instead

 

[vigilante398]

@vigilante398, is a 25v cap in C4 ok?

Tassie is correct (which is to be expected, I think he's built everything I make at this point).

 

[Tassieviking]

Nearly everything I can get my hands on, when the time is right I won't delay even a second to build the last one I know about.

I can't help myself
The urge is just too strong.

Cheers
Mick

 

[vigilante398]

Nearly everything I can get my hands on, when the time is right I won't delay even a second to build the last one I know about.

I can't help myself
The urge is just too strong.

Cheers
Mick

I have a mostly functional build doc for Solaris, just missing drill template (I think it's the same as Lab Rat without the toggle switch) and the detailed build instructions (same build process as Lab Rat, nothing weird). I'll get that one out soon.

 

[Tassieviking]

When I used to make my own PCB's for pedals I usually stuck to the same drill layout all the time, it makes it so much easier and you can keep a spare enclosure with all the different drill holes in it at home for all the test PCB you make, you can box any PCB up so you can safely test them with the "test" enclosure.
I was lucky that I hardly ever had to throw many PCB's away since I was making PCB's of known circuits just because I wanted that specific pedal, and it was soo much cheaper and fun rolling your own.

 

[Tassieviking]

This is my drill layout that I have made from all the C2CE 1590BB Drill Files, I start any tracing of any C2CE PCB with the drill file layout in KiCad so I get things right. I used it when I made my little 1w tube amp in a 1590BB2 case so I got the tubes in the right place.
Each pedal has it's own User Layer and I know the Ambassador, BassDude and Black Eye use basically the same layout for pot positions, I also have the position for any mod switches drawn in a layer as well.