STRIKER VALVE DRIVER SCHEMATIC

[Striker Amplification]

Pin 9 is optional, only if you want a faster warm up time frame will you use pin 9.

[Bill Mountain]

I'm pretty sure he's running them in series and under-volting (is that a word?) the heaters like a Valvecaster.  That would make the most sense.

I've read that starving the heaters can cause thermal stripping (I think this was a reference to power tubes though) and I've also read that starving the heaters can increase linearity but I think the range for that was only down to 10 volts or so.  I've never seen anything concrete on whether 9 volts in series is safe or not.  I've done it on the breadboard but never built a Valvecaster so I don't know the long term effects.

If done in parallel I think it's safe to go about 25% over the specified voltage so that would be 7.8 volts tops.  You could put a series resistor or diode to drop the heater voltage to safe-ish levels.

[Striker Amplification]

Good point bill , but as long as the transformer produces a decent amount of amp output, you can get very nice long term results. I still have the prototype running on the same adapter, 4 years and still running strong.

[Jdansti]

I connected pin 4 to ground and pin 5 to primary, using 9VDC.

Got it - Thanks!!!    I was hoping that was what you were doing. I'd caution going too long (or at all???) with pin 9 grounded, as this puts the voltage at 150% of the rated spec for parallel heater configuration (as R.G. noted).

I'd really like to hear this sucker!  I need to see if I have a 12AU7 laying around. 

[Striker Amplification]

Right you are, way too much power power draw with pin 9 grounded. Hopefully i get a video uplaoded shortly. The pedal sounds very much like superlead plexi but smoother, not as harsh at times certainly not as flabby

[kingswayguitar]

Right you are, way too much power power draw with pin 9 grounded. Hopefully i get a video uplaoded shortly. The pedal sounds very much like superlead plexi but smoother, not as harsh at times certainly not as flabby

sorry, i read this, went away, but couldn't get this quote out of my head. this is the first time i've heard the words "flabby" and marshall used in the same sentence. hendrix, metallica, ac/dc, early clapton, van halen, FLABBY??!!??

but to each their own.

peace!

[Striker Amplification]

Jim marshall is the reason i started building man , i love marshall to death, just some of the early plexi had a very bassy overtone at lower volumes.

[kingswayguitar]

Jim marshall is the reason i started building man , i love marshall to death, just some of the early plexi had a very bassy overtone at lower volumes.

actually i very much agree with that
i play a bassman by the way 

[mistahead]

Laney Vs. Marshall I consider adding Flab to similar ideas... but others probably call it something else, loose bottom end is one man's magic and another man's bane, or both depending on who you are playing with (other guiar, lots of toms, etc).

Starved plate does make for a "shorter lifespan" on tubes doesn't it? Just like turning up the amp to 11 does compared to running it in the middle of its preferred enviro... But tubes are a consumable (with a longish life) anyway - you either push them to the brink or starve them to death but either way you expect to replace them one day...

Just thinkin'

[Striker Amplification]

59 bassman!

[PRR]

> about a 50% over voltage on the heaters. This would burn them out fairly quickly if.......

6V heater run at 9V: at least 50 hours. Plenty of time to do a lot of testing. Not unaffordable doing paying gigs.

If no sonic difference 9V or 6V on heaters, 10r dropping resistor is the elegant hack.

However further info suggests 9V on the 12V connection. This leads to about a 2-century heater life.

> I've read that starving the heaters can cause thermal stripping (I think this was a reference to power tubes though)

Right, Power tubes. Not a 300V 3mA tube working at <9V and <0.1mA.

> I've also read that starving the heaters can increase linearity

By increasing cathode internal resistance. Has essentially the same effect as sticking a resistor under the cathode. Ryan's has no cathode resistors. Maybe the cool cathode is part of his bag of tricks. Or maybe at this very low current, it does not matter. Anybody who actually CARES can whip it out, feed variable 12V to the 12V connection, and hear for himself.

No comments on the positive-grid mode on the second tube? Variable with Volume setting. An interesting trick. The 10Meg-50Meg grid resistor follows from that.

[Jaicen_solo]

So, I guess somebody should ask whether you've scoped the outputs of the tube section, as it looks to me like they would be fairly linear, in which case you could probably stick a FET or MOSFET or even an op-amp in there, without hearing a difference.

[artifus]

[artifus]

i'm no good at math(s) but i'm guessing the calcs are pretty much the same.