5678 sub mini projects?

RnFR · Post by **RnFR** » 21 Dec 2011, 00:30

so i recently picked up 20 of these little guys up on ebay recently for cheap, but have been having a hard time finding projects for them. anybody know anything off hand, or what i should do to adapt other submini schematics?

frequencycentral · Post by **frequencycentral** » 21 Dec 2011, 01:00

Almost identical to 5672 which I've used a lot. I think the pinout is changed for a couple of pins. Probably microphonic due to the (spring) nature of the filament.

Easy way to power the filament is a LM317, without any resistors it will naturally give 1.25v. Or use a 220R 1 watt resistor instead.

I know some people have used 5672 to make Pentaboosts.

https://www.diystompboxes.com/smfforum/ ... #msg569387
https://www.diystompboxes.com/smfforum/ ... ic=70533.0

As for an amp, you could certainly cascade a few together for a preamp section, and also maybe run a few in parallel for an output section.

They're ugly lookin MF's though ain't they?

RnFR · Post by **RnFR** » 21 Dec 2011, 02:18

yeah, kinda ugly. i don't really care about that though. actually, i kind of like the looks of them. very "industrial".

i got 20 of them for something like 15$. many raytheons. i'll try and check out some of those 5672 projects. i was thinking something with some decent voltage, most likely a preamp. i could always use a different tube for output if i went for an amp. so, you think i'm going to have some problems with microphonics? thanks for the tips!

RnFR · Post by **RnFR** » 21 Dec 2011, 11:40

Rick- have you ever tried using that max1044 50v supply with an overdrive like the pentadriver/pentadriver turbo? is there a clip for the turbo mode? i havent been able to find one. or how about using these little pentodes as triodes?

frequencycentral · Post by **frequencycentral** » 21 Dec 2011, 14:16

An early version of what ended up as Murder One was 3 x 5672 cascaded @80v, so yeah, it's good.

I never did a clip for the turbo mod, higher voltage is the way to go really, the turbo mod was a bit fakey.

To make em into triodes connect grid 2 to the anode.

This is on the breadboard at the moment:

These are two DM160 indicator tubes http://www.r-type.org/pdfs/dm160.pdf They're the smallest tubes I've ever seen! I'm cascading them into each other for overdrive. I'm running them from a 120v SMPS

. They flash in time with my strumming.

I was thinking of entering it into the competition's Dirt Catagory.

But they're microphonic as hell.