Amp in a pedal.

[Koolaide]

Hi all,
I have been pondering a tube preamp into class D power section ala "milkman the amp pedal". DIY. I know the subject of tube preamp + s/s power is an old one. However, I was not able to find any real DIY information.
So I have come to the folks I think have the real skills and knowledge to help me sort this out-TAG.
My thought is to build the Hoffman Tube preamp pedal and mary it to a cheap class D power section. I am hoping this would produce good tone, portability. I know it will not produce any holy grail tones. I just don't want to end up with an unusable cold ice pick sound.
I have been really intrigued by the DV Mark micro amps and to some extent the aforementioned Milkman amp pedal. I have scoured ye ol internet for schematics, information and clones of these but had little success.
I am wondering if the preamp will produce tube warmth. or will it simply act as an overdrive to the power section and produce crap for tone?

Any help or thoughts appreciated.
Happy Holidays,
Jim

[Blindog]

Following...I've been pondering the same.

[thetragichero]

i abhor cliches like "tube warmth"
that being said, make sure you attenuate the tube signal enough to feed the power amp a signal size it's looking for... too large and it'll definitely clip unpleasantly (at the least), too small and you won't get the volume you need
keep in mind that unless you're going for a starved plate design you'll need hundreds of volts (at very few mA of current) while most of the cheap class d boards/chips off eBay are looking for low voltage (12-27v ish) and high current (some as high as 5A or so)
like every well thought out project, spend the most time planning the power supply as that could make or break it

[10thTx]

Years ago, I built a tube preamp with an overdrive channel (for an electric guitar) that ran into a PA system. It sounded just "OK".

However, I thought it lacked warmth and so I added 6K6/6V6 tubes in as power amp as an option and used a H&K Red Box and a dummy load resistor to run it into a PA system. The idea was trying to get a tube tone with a zero volume stage amp set up. This worked quite well as just a head with NO cabinet was needed & it had relay switching on a two button foot switch. This has worked great and has had reliable weekly use since 2013. I will say this particular amp cut thru the mix extremely well with keyboard, acoustic guitar and a variety of mandolin, violin, cello, etc...….

I realize this is NOT the same as what you are suggesting. However, it is an example though of trying a tube preamp into a solid state power amp.

AND ………………………

I also did a tube preamp for an acoustic guitar into a PA system. That worked quite well, IMO. The top photo and schematic are the acoustic.

With respect, 10thtx

[pompeiisneaks]

I've been toying with building a Class D amp for a while and am about to embark on that. Then the idea would be to be able to buy a less expensive transformer for maybe 40$ that gives me 300VDC for the preamp side, add filtering and have a preamp into a class D power stage. Gives you quiet bedroom levels easily AND can go up to mad watts like say 300 or so of solid state output.

I'll share more as I get the idea going.

I've posted the infineon schematic into the pcb section already, but in my case the only pcb part will be a SOIC-16 breakout board that I can then connect into an eyelet board for the rest of it.

~Phil

[printer2]

On my to-do list. I will have a lot more time next year so it should get done. I would like to try a couple of different flavors, simple



Probably can use a voltage divider before the FET.

And a little more.





A 18V laptop PS, a high voltage module bought online, Class D module. Have a digital reverb chip to go with it. A lot to fit in but doable. I cut the fins off the heat sink, not needed with the current being drawn. Need to breadboard it first so just view it as a wild-ass idea for now.

[thetragichero]

I've purchased a few of these class d boards from eBay and never considered a tube preamp for them. they've just been sitting for 6months as other projects have occupied my time. will have to get to thinkin

[Koolaide]

Thanks everyone for your replies to date.
Does anyone have a schematic or gut shot of a DV Mark Micro series amp?