thunderchief - tube

[changes]

well just a thought for the thunderchief pedal...
i'm not sure because i'm new to stompbox building but the distortion is coming out from the second jfet.correct?can i replace that fet with a 12ax7 or any other triode(i have a pcl 86 waiting) and retune the pots for 4.5v.if this is possible i believe that the sound will be even better and closer to the original.
pleaz correct me if i'm mistaken

[YouAre]

I have long....longed...to have tubes in my solid state pedals, but from what i've learned, its not really practical. You will not get alot of power out of those tubes at just 9v.

[Lonestarjohnny]

What kind of amp are you playing your Thunderchief through, I've played mine trough about 25 different amps and you'll laugh, but, I think it sound's so warm and just like my old Plexi when I play it through my old Peavey Classic, it's got a S/S pre/amp and 2 6L6's for power, I'm gonna put some new speaker's in it next week and start useing it at the Jam's I go to. I can't wait to see some of the Guy's reaction's when I haul that ol Dog in to the Gig, But what will really be fun is When my Peavey rip's the ass right off of one thier LIL BoPeeP Amps, believe me, I don't work for ROG but I'm sure gonna Advertize for um,
JD
PS { I hope I don't make the price of Peavey Classic's Shoot Sky High on UKBaY } I paid 25 for mine at the Flea Market.
 :lol:  :lol:  :lol:

[changes]

i know that you re gonna have less output with a tube at 9V but i think it will do...
the thunderchief with all four jfets has much more output than almost any other pedal...
if i replace the second one with the tube then the output will probably be like any other stompbox...and if not i could supercharge the tube by increasing the cap,resistor values...

[Ed G.]

PS { I hope I don't make the price of Peavey Classic's Shoot Sky High on UKBaY } I paid 25 for mine at the Flea Market.

A friend had one, it had 2 Scorpion speakers and was seriously LOUD. You are talking about the older model, black tolex, right? His had a built-in phaser. I didn't care for the distortion sound, kind of ratty, but I bet a good distortion pedal in front of it (like the excellent Thunderchief) would make it smoke!
I think those old Peavey tube amps are good finds. Wasn't the Butcher basically a JCM 800? And at least one Soundgarden album was cut with a Peavey VTM (vacuum tube modified) whose 'mods' were activated by a little DIP switch right on the front.
I remember seeing a Peavey tube amp at a pawn shop that had 6 (that's right, SIX) 6L6 output tubes. It was a 2X12 combo and heavy.

[Lonestarjohnny]

Ed, I've played tube amp's all my life and I would laugh at anybody beside's the Bass player if they suggested a S/S amp for guitar, well the Boy's over at ROG have changed this Old Dawg's way of thinkin,
The Peavey's are super cheap here in So. Texas, mine is a Classic 50,Black Tolexed, 2X12 combo, S/S Pre and 2X 6L6 power section, I repaired it after finding it at the Fea Market, 1 bad transistor and a set of rebaised tube's, cleaned the pot's and jack's, tightened everthing up and she sound's like a million dollar Speacial. By it's self it has some tone but not enough to brag about, But With 1 of ROG's Emulater's in front of it, it make's any of my other gigrig's sound weak, that goes for my collection of Botique amp's also.
I have a 6X6L6 head but will be in process of building it into a 4X12 or 6X10 combo, and I have a New pedal I'm building that will drive it, I'm putting 8 different Emulator's in 1 larger control box with a Custom Volume Pedal and Wha built in the same house'ing. if this won't Flip your Skirt, Nuthin Will, LOL !
Most people pass these amp's up in a hurry, they just don't know what they are missing, I'm gonna rebuild mine with some better quality cap's on the board and install a set of Weber speaker's, I'm gonna do a lil at a time and test, I don't wanna mess up the way these amp's respond to ROG's Circuit's.
JD

[changes]

well i did replace the fet with the PCL 86 i had (the triode section) but nothing coming out.almost nothing.when i top the volume from the amp i can hear a weak clean sound no clipping at all.
i even increased the supply voltage to 18V but with no better result...
pleaz help..
could it be the tube?
it's the first time i use one...
so follkowin the instructions at runoffgroove i replaced the legs of the fet with the anode,grid,cathode of the triode and then grounded the tube(did i have to do that?).
do i have to connect anything to heaters
i don't have a clue about tubes......

[petemoore]

I'm running 12ax7's heaters at 11,2v, measured with load, coming straight from a 9v dc wall wart.
 You should see the small orange glow of the heater in the tube, less than a minute after power is applied to the heater circuit. Use pins 4 and 5, which are rated at 12v.
 You can run the heater off the 6.3v rating...using pin 9 for - and pins 4 and 5 tied together for the +. you can invert the polarity to the heaters ie - to one connection and + to the other...
 Cathode >source
 Grid > Gate
  Plate> Drain
 You should know the pinout of your tube of course.  
 Different tubes have different ratings, check the ratings for the tube your intending to use, it could be differnt thatn the 12ax7.

[changes]

well i soldered the heaters and supplied them with 11.5V (at 17.2V power supply)
but there was no glow after 5 minutes and still no sound
could it be the tube.It 's a PCL 86 from an old tv that was working...
the anode is at 10V
is it maybe too high?
do i need to solder the heater with another part of the triode...
i'm crazy now i want to make it work...
grrr

[puretube]

the PCL86 needs 14.5V to get 300mA running thru the heater;
do you have the correct pin-out of that tube?
what do you mean by "grounded the tube"?

[changes]

i think i have the correct pinout i dloaded a pdf for the PCL 86
well i connected the centre of the tube with ground...not one of the pins just etal centre but probably does nothing so say i never did it.
I i understood what you said i have to aise the voltage of the heaters to 14.5V
(does it matter that i have the heaters soldered together???)
i will do what you said and i'll tell you the result asap

[puretube]

you should measure 14.5V between pin4 & pin5

[petemoore]

According to The RCA Tube Manual, IIRC, it stated rating tolerances of + or - 10% ...generally, and for the filament.
 If your tube is rated at 12V for 'that' way of connecting the  heater filament, 14,5v's a little on the high side. Are you measuring the filament PS voltage under load [while connected to the filament]?

[puretube]

PCL86 is rated 14.5V / 300mA !
(series-heated, AC or DC)

[Peter Snowberg]

[puretube]

!!! and always be aware of the bottom-view/top-view factor!!!

(mis-taking this, has lead to the E-H Tube-Zipper, some 32 years ago...).
:wink:

[changes]

ok you guys i know i am a bit annoying with all these questions...and thanks for the interest...
puretube what do u mean between pin 4 & 5?
do i have to put one connection of the multimeter to pin 4 and the other to pin 5?or not cause
I told you i soldered those 2 pins together and then measured the voltage to ground and the mm showed 14.7V.still no result i m starting to think that it is probably the tube
when in the manual says the pin numbers i believe that it is looking at the bottom of the tube right?

[puretube]

:roll:
look at the pic, Peter posted at bottom of last page:
pins4 and 5 are the respective ends of the heater, and should be connected to Uf (thats how we name the heater, or filament supply),
in this case 14.5V.

I asked to measure that,
to be sure you don`t shortcut them!

[donald stringer]

As i read  these posts on peavy amps I am close to crying. Before I realized the beauty of tubes, I had no less than two peavy amps: VTM with thephaser/paralel effects loops scorpion speakers and another similiar to the vtm alltube of course. But for the life of me I couldnt get a decent crunch out of them. Now I know I was looking for the wrong tone and actually didnt know[at the time] how to achieve what I was looking for. I let them go for a song. But I will be on the look out for them again. In the meantime I am keeping my classic 30. I play it thru an univox 4 spk. cab wired for 8 ohms. I have an fender pro 185 solid state that I keep on the clean channel [which is how I test my pedals] and an crate dx 212 /the one with the amp and effects models.

[changes]

ok i m beginning to think i'm a complete idiot...
this is what i have done so far...
i wired anode for drain that is pin 9 and i measure 10V to ground
grid for gate pin 1 and i measure 0V to ground
cathode for source pin 2 i measure 0V to ground
also wired pin 4(heater) in series with a 470k resistor to the battery supply
and i measure 14.7V to ground
and wired pin 5 heater in series with a 50k resistor to pin 4 and measure 10.9V between pin 4 and pin 5.
what else do i have to do or what have i done wrong?