Simple point to point tube distortion ideas

[printer2]

A 12AX7 on low voltage is a waste of time. Go to a thrift store and see if you can find a wallwart that puts out 12-13V with a transformer in rather than a switching power supply. And as much as I don't like the idea, get another one, could be low current, and put the low voltage winding on the 12V of the other one and rectify the voltage that comes off what would normally be the primary.

http://www.charlestonarea.com/mctube/real_mctube.htm

[EBK]

For higher voltage circuits, are nixie tube supplies any good?
Im looking at this one: https://www.amazon.com/dp/B074N5LVFH/ref=cm_sw_r_tw_awdb_x_Xb87zbH8JKN4X

Otherwise, I had been looking at this supply:
http://diy-tubes.com/index.php?route=product/product&path=59&product_id=565

Chris, I hope you don't mind my continued barging in on your thread....

[Chrisfromiowa]

Arent those like deathly high voltage? Trying to thin the herd?

[EBK]

Arent those like deathly high voltage? Trying to thin the herd?

About 230VDC.  Potentially lethal, yes. 

[Chrisfromiowa]

I'm old and collect power supplies so I've got a whole box of them, including a 12 point something volt dc I figured I'll use. One of the valvecaster layouts on the PDF uses 12v so I thought I'd just wire it directly into the unit since it has its own fuse built in. I've seen all of these versions using 120/240 with step up/step down transformers and if I was going to do all that I might as just build a new amp..... Now that does sound kind of cool, an old style point to point wired tube amp... find a couple of those big transformers to make it look brutal... OKOKOK, stop, I've got to get back to work.

[Chrisfromiowa]

A 12AX7 on low voltage is a waste of time. Go to a thrift store and see if you can find a wallwart that puts out 12-13V with a transformer in rather than a switching power supply. And as much as I don't like the idea, get another one, could be low current, and put the low voltage winding on the 12V of the other one and rectify the voltage that comes off what would normally be the primary.

http://www.charlestonarea.com/mctube/real_mctube.htm

Damn, that looks very cool and the land o lakes woman always gets me going... I've never searched Land ' lakes girl but this image was the very mildest of the results.

[printer2]

For higher voltage circuits, are nixie tube supplies any good?
Im looking at this one: https://www.amazon.com/dp/B074N5LVFH/ref=cm_sw_r_tw_awdb_x_Xb87zbH8JKN4X

Otherwise, I had been looking at this supply:
http://diy-tubes.com/index.php?route=product/product&path=59&product_id=565

Chris, I hope you don't mind my continued barging in on your thread....

These are pretty nifty.

http://www.ebay.ca/itm/DC-DC-8-32V-to-45-390V-High-Voltage-Boost-Converter-ZVS-Step-up-Booster-Module-/322374615632

[Chrisfromiowa]

For higher voltage circuits, are nixie tube supplies any good?
Im looking at this one: https://www.amazon.com/dp/B074N5LVFH/ref=cm_sw_r_tw_awdb_x_Xb87zbH8JKN4X

Otherwise, I had been looking at this supply:
http://diy-tubes.com/index.php?route=product/product&path=59&product_id=565

Chris, I hope you don't mind my continued barging in on your thread....

These are pretty nifty.

http://www.ebay.ca/itm/DC-DC-8-32V-to-45-390V-High-Voltage-Boost-Converter-ZVS-Step-up-Booster-Module-/322374615632

Btw, not at all, I do it all the time, I consider forum threads like conversations at a party, if you have something to add or a question you should be able to join in, at least in my opinion. Case in point, I would have never considered higher voltages, but that little guy is pretty cool. So, you could take a point off your daisy chain and step it up pretty easily with this, right? And the little set screw would keep it at a constant level without having to rewire a transformer... right?

[MaxPower]

I have a tube preamp circuit from an electronics mag so probably a no-no to post it? Anyway, it uses a switchmode/switching regulator (mc34063), inductor, cap, mosfet,  etc. to boost 12.6 V up to about 265 V. I'm sure the gurus here can whip out an example circuit should they care to do so. Might be a decent alternative to using step up transformers, though that booster module does make things easy and isn't expensive.

[EBK]

So, you could take a point off your daisy chain and step it up pretty easily with this, right?

I'd want a three-prong AC plug going into the box that holds this, so I can attach a safety ground.

I feel like I need to do some math first to figure out what amount of current I need.

[Chrisfromiowa]

I have a tube preamp circuit from an electronics mag so probably a no-no to post it? Anyway, it uses a switchmode/switching regulator (mc34063), inductor, cap, mosfet,  etc. to boost 12.6 V up to about 265 V. I'm sure the gurus here can whip out an example circuit should they care to do so. Might be a decent alternative to using step up transformers, though that booster module does make things easy and isn't expensive.

How old is the mag, is it new enough I could find it in the library? Thanks

[duck_arse]

those circuits are often called "nixie" supplies. they very often have a trimpot to allow the output voltage to be adjusted - the circuits are also very easy to hack for lower voltages, run 60V, 90V, 134V if you like.

[MaxPower]

I have a tube preamp circuit from an electronics mag so probably a no-no to post it? Anyway, it uses a switchmode/switching regulator (mc34063), inductor, cap, mosfet,  etc. to boost 12.6 V up to about 265 V. I'm sure the gurus here can whip out an example circuit should they care to do so. Might be a decent alternative to using step up transformers, though that booster module does make things easy and isn't expensive.

How old is the mag, is it new enough I could find it in the library? Thanks

Hopefully this isn't considered spamming. Anyway, it's a two part project in the Jan and Feb 2017 issues of Everyday Practical Electronics. It's a UK mag. There is a digital version which costs $2 US. The schematic and parts list are in the Jan issue.

[EBK]

I've ordered a copy of Merlon's book, Designing Tube Preamps for Guitar and Bass.  Loved the info on the Valve Wizard site, and I'm eager to learn more.  Besides, a preamp seems to be where I'm heading for the sound I want.

[Steben]

Lately I have come to the point where the whole concept of tube tone is far from preamp tubes in high gain use. Of course running on low voltage suits distortion circuits better. High gain on the other hand is not where tubes shine the most. As mentioned triodes are quite linear with a hunch of even order harmonic content. It may be non mainstream yet a booster could be nice.

[amptramp]

This site:

http://diyaudioprojects.com/mirror/members.aol.com/sbench101/

has distortion curves for 12AX7 and other tubes with operation with a 250 VDC supply voltage plotted against RMS voltage output.  Other parts indicate how well various tubes do with starved filament current.  This will give you hours of reading until you get to the point where you wonder why you asked the question.