"Promiscuous Girlfriend" So many types of dirty with 5840 Submini Pentodes

[Strategy]

thanks rick,

are the pots in your pdf as though from front (turny side) or back?

thanksmuch!

strategy

The way I remember pinouts for these subminis is that there is a gap between pins 1 and 8, over than that they correspond to a dual opamp, so looking down on the tube is the same as looking down on a dual opamp (if, as I do, you create another gap between pins 4 and 5 for insertion into the PCB, SIL strips or whatever). Anyway, there's a little diagram showing the pinout in the schematic on the first page of this thread.

[Strategy]

got this thing working last night- beautiful!!! tried it with guitar, synths, keyboards, drum machine...amazing!

Debugging: I can't tell if the switchable diode clipping is not working or simply very subtle. I used an SPST toggle on/off, I used 1N4148s and they are in the correct orientation. I'll check my soldering on this piece - is the diode dirt intended to be subtle or significant?

thanks much
strategy

[frequencycentral]

Glad you like it. It seems to be a well kept secret. Few have built it but all seems to love it.

There's a few things you can do with the diode clipping. Reducing the 1M resistor will increase the clipping, even a pot might be useful. You can 'tune' the frequency of the clipping by changing the 0.0047uF cap value, even a 3 or 6 way cap selection switch might be useful. You'll have to experiment with values.

[Strategy]

a 1M pot to replace that resistor or should I go for something smaller?

I feel I could have a mistake in my dirt switching. the switch seems to do almost naught. I am going to check my soldering again and maybe try a different switch...Seems you have depicted in the diagram an SPDT with one pin not connected (?) I used an SPST on/off instead. Switching always confuses me, is there really a difference between what I've done and your diagram in terms of functionality?

thank you Rick for this fun circuit

I'll post my build in which I used a sloping LMB enclosure and drilled reveals so that I could have visual and heat venting while not having my tubes poke out of the enclosure...Its almost done...very industrial looking but crafted

Strategy

[frequencycentral]

a 1M pot to replace that resistor or should I go for something smaller?

It's been a couple of years since I made that pedal, and I don't own it anymore. I'd suggest installing sockets for the resistor and cap. That way you can play around with values until you hit on perfection. You will probably find that the optimal for replacing the 1M is a resistor and pot in series, so you have at least some minimum of resistance (which you will certainly need). But yeah, try a 1M pot, see how useful it is at either end of it's throw, measure it.........you *might* end up with a 500k pot and a 220k resistor in series (for example).

[Strategy]

A little resoldering got the dirt switch operational. I'll try the socketing after I know this thing is stable.

So, I started the 'boxing it up process' and had to stop mid way as I mis-drilled my enclosure and I'd rather start again than have something with wrong holes. In any case I have some trouble shooting to do:

Surprise #1:
I hadn't soldered the MAX1044 all the way in! When I tested it it worked great so I assume that it had enough contact to work fine. Fortunately it wasn't on for very long this way. Less than 5 minutes. Promptly soldered it all up before powering it on for the second test!

Surprise #2:
There's a low-mid, steady hum at all times which becomes more present as I increase the volume knob. I've gone back and checked for grounding and continuity issues and can't seem to locate it.

This is my first tube project:
Could this be a tube issue?
Is this normal and I'm just cranking it so high the noise floor is abnormally strong sounding?
Is this pedal best served by shielded inputs and outputs wiring?

Thanks for the help with this- really wanting to get this one going

Strategy

[Strategy]

bump - anyone else get hum? increases with use of volume knob?
doesn't sound quite like ground hum?

as a tube noob, any advice would be appreciated!

strategy

[frequencycentral]

Hum. 99% possibility that it's coming from your power supply. Tube heaters are sensitive to unregulated/poorly regulated supplies. You could try a big ass electro cap across the supply rails. Or powering from a higher voltage PSU (15v) via a 7812 with a 100uF cap at it's input and output.

[Strategy]

hmmm...I'm using this:

http://www.smallbearelec.com/Detail.bok?no=1006

Not good enough? Can anyone stateside tell me a wallwart that might be preferable?

Strategy

[Govmnt_Lacky]

hmmm...I'm using this:

http://www.smallbearelec.com/Detail.bok?no=1006

Not good enough? Can anyone stateside tell me a wallwart that might be preferable?

Strategy

Although Steve sells many wall warts at a good price.... alas they are NOT regulated.

I could suggest a 1Spot. They are very quiet. Just give them some time between unplugging them and handling the contacts 

[Seven64]

how do you get the "tube guards" on the enclosures?!

[Taylor]

I could suggest a 1Spot.

I use a 1spot and like it, but this project requires 12v which the 1spot cannot supply, so it's not an option here.

[frequencycentral]

how do you get the "tube guards" on the enclosures?!

Bolted on from below of course. One short pair of bolts, another long pair with 15mm M4 nylon spacers to mount the circuit board. It's how I do my amps too.

I could suggest a 1Spot.

I use a 1spot and like it, but this project requires 12v which the 1spot cannot supply, so it's not an option here.

Might be easier to us an AC supply, rectified, filtered and regulated.

[Seven64]

i should have re-worded that.

what are they exactly?  just stainless steel tubing or something like that?

[frequencycentral]

i should have re-worded that.

what are they exactly?  just stainless steel tubing or something like that?

They are drawer handles. Bought from B&Q in the UK. Sorry to compromise the mystique. 

Here's another PG based pedal, with Vox tonestack and Bblender:

[Strategy]

Jameco seems to have linear regulated 12V supplies of various sorts as wall wart.

[Strategy]

Confirming from my last post, 12V linear regulated Jameco wall wart works...HUM FREE!

As soon as my enclosure gets here this baby will be ready to go...pics to come!

Strategy

[frequencycentral]

^^^ Cool! 

Here's a soundclips of the Moon Unit (pics above) done by it's new owner:

[Strategy]

OK finally got this one off the ground! Sounds great and full build pics here

http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg788305#msg788305

[frequencycentral]

^^^

Looks really good Strategy!

Here's my next one: