High voltage pedal like Victory Kraken

[temol]

Looking at the GTFO and 5150 schematics, they are very similar.

Because 90% of the tube preamps looks very similar.

I do not have part numbers for GTFO board I've mentioned to you. Just take the schematic posted couple posts above and make a shopping list.
Here - https://www.diystompboxes.com/smfforum/index.php?topic=93936.380 you'll find voltage ratings for the capacitors. I recommend you to read the whole GTFO thread two or three times.

ps. I'll check if I can get his emaill address.

[alexradium]

Looking at the GTFO and 5150 schematics, they are very similar. I attached a copy of the 5150 schematic where I highlighted the components that are in the GTFO, and wrote in red the changed values to make it a GTFO. Just a FYI

GTFO is the SLO preamp minus the cathode follower and single tone control,Peavey copied the first stages and added an anode follower to flip the phase and drive the tonestack,then in second version did a tighter version with the 470p cap after first stage.
Mesa DR is copied verbatim from the SLO,as well as HK Triamp,Framus and many more.

[diydave]

If I we're you, I would try to put a heatsink of some sort on the heater voltage-regulator. Although it's rated to handle 1 amp of current, I had 'breakdown' using it the same way you would do.

[caspercody]

Yes I will put a heat sink on it, thanks for the idea

Thanks for the info on the amps. So do the last two stages on the 5150 add anything to the distortion of the amp?

Seems like the big difference between the amps then would be the tonestack used?

[GibsonGM]

Using more stages to distort and let you do it 'slower'.  You can get a high level of distortion which will be warmer by using more stages - you will have a slower onset of clipping, yielding more even harmonics -....the 'character' of the amp may be different, depending on how you set up all of your stages ("gain staging").      Often, with fewer stages you try to hit each stage with a higher signal level, to get a harder sound, and that can be more raw.  On the other hand, if you don't design 'correctly', you can just get a fuzzy mess out of the other 2 stages, ha ha. 

Yeah, the tone stack is a MAJOR part of the character of the amp!   Sometimes the magic is just in using a mid scoop, or raising the mids for more punch.   You can get ideas about this by following a preamp with an EQ pedal.    You can go from Eric Clapton bluesy, to modern hard rock pretty easy, many times.    There are tricks that manufacturers use, of course....tone shaping between stages.  That makes a big difference, too.

[caspercody]

So I have bought some of the PCB's for the GTFO, per the recommendation from Temol, thanks!! And both that I have built, so far, work great. I turned the GTFO into a Soldano 50 mod, and a Landry LS100. The Soldano has (3) tubes, while the Landry has (2). The Landry does squeal with gain up above 60%.

The one issue I have is with a LED connected to indicate power, as I turn up the volume the LED gets dimmer. Also as I turn up the volume it crackles (kind of like ZVEX SHO does). So for now I removed the LED, and it does not crackle, but it would be nice to have the power on indication.

I am using a 3PDT switch with a resistor to +12 vdc, and switching the LED to ground. I do not remember the value of the resistor, I am guessing 1k. I have a feeling that this is creating a voltage drop. Should I use a higher resistance resistor, or another means to indicate power?

Thanks
Rob

[tubegeek]

"crackling" on a volume pot could be a symptom of DC through the pot - usually volume pots are either coupled through a DC blocking cap or fed by a circuit point with negligible or 0 DC, just the AC of the signal through it.

The crackling - I don't think? - shouldn't have anything to do with the LED, but if the LED is dimming off the volume control, something's not connected right.

I have a slightly different take on a high voltage tube preamp like what you're doing, it's "under development" at this point but there's a build thread here, you might want to take a look. Link to the discussion is below. I'm using the same "nixie" power supply as the other projects, but I also bought a few really cheap power supply modules off of ebay, I'll try and find the link and post it later. These have a little more "beef" and include a heatsink for the boost converter, they'll run a bit higher voltage/higher current depending on what you need and how they are adjusted. They also have a fuse which is nice. But the nixie supply is likely plenty for what you're doing anyway. Be careful with the high voltage side of the power supply - I'd hate to lose a fellow tube dude!

I test my nixie supplies with 30 ohms (3x10 ohm 5W resistors in series) across the 12V side (to mimic 400mA of 12V heater current) and 20Kohms (5W rating) across the high voltage, so that's 10mA at a setting of 200V. I have found that - depending on layout - some of my nixie supplies have acted weird when run unloaded, just a heads up. If you're using a PCB from a tested layout you probably won't run into that, mine were ad hoc perfboard builds and it was only the first one or two that misbehaved.

Go over PRR's comments on the power input requirements - if the 12V side is sagging too much you just need a higher-current DC adapter that will deliver 15 or so VDC at the load you are running, especially if you want to run a regulator for the heater feed. The high voltage side draws more than the 5 or 10 mA you see - you calculate by the power consumption (so V*I) and then derate that a bit because the conversion is not nearly 100% efficient, figure maybe 2/3 so you need 1.5 times the wattage you are actually using, plus the wattage for the heaters.

Don't run the nixie supply off of the regulated 12V, run it directly from the DC adapter and parallel the 12V regulator from that adapter's feed - you don't want to drop the adapter voltage before the nixie supply.

I second the recommendations up the thread for the subminiature type tubes - they are about the size of the high voltage coupling caps, and sound pretty great!

https://www.diystompboxes.com/smfforum/index.php?topic=106605.0

[caspercody]

I have built (4) different pre amp pedals and all work great. I now want to build a Mesa Mark V, and I have almost everything planned out but I have a question on the pre amp schematic. Per the attached photo I circled the part I have a question about. So do I need all the parts circled? To me it seems some of these parts might be there for the reverb and really not needed or if removed will not effect the desired tone. Please let me know what you think

Thanks
Rob

[PRR]

> do I need all the parts circled?

Yes, or equivalent loss.

V3A + V6A is way too much gain before a knob. V6A would clip uncontrollably. V3A alone is not far below clipping on strong plucks. So we expect a loss network with 25:1 or 50:1 loss. I'm not sure what all-that does. Counting on thumbs it looks like 60:1 loss. And for the price of six resistors, blind-copy is cheaper than brain-pain. ($2 for resistors and turrets; $20 value of thinking-time.)

[caspercody]

Thank you!!!