...and now, the "PentaDriver" 12 volt Pentode Overdrive using Submini 5672 tubes

[obelix]

be waiting for those soundclips 

[Renegadrian]

One of my friday night's beers is for you, Rick!!! 

[frequencycentral]

Ok, here's a soundclip: http://www.aronnelson.com/DIYFiles/up/PentaDiver.mp3

Squier Telecaster Custom (HB) bridge pickup  >  PentaDriver  >  soundcard (Event Echo Gina 24)  >  Wavelab

PentaDriver set with 'Gain' and 'Tone' full up. No processing other than the PentaDriver (it's kinda weird playing so 'dry'!)

..........and some photos:

[comfortably_numb]

Would you be able to play with that through a miced amp and record it?  Really hard to tell what it can do like that. 

[frequencycentral]

Would you be able to play with that through a miced amp and record it?  Really hard to tell what it can do like that. 

Yeah, I'll do that on Monday - I don't have a microphone here at the moment. I thought I should record it straight into the PC so there was nothing else 'colouring' the sound. You could play the soundclip through your favourite guitar amp though....................isn't that called 'reamping'? Or process it through a cab sim???

[tranceracer]

That sounds really nice (dry).  I'll bet it will be even better hooked up to an amp or amp sim.  I like the tone, not harsh and the distortion cleans up nice when you hold the note. Well, add this one on my to do list!   

-bK

[doug deeper]

was that dont shake me lucifer?

[frequencycentral]

That sounds really nice (dry).  I'll bet it will be even better hooked up to an amp or amp sim.  I like the tone, not harsh and the distortion cleans up nice when you hold the note. Well, add this one on my to do list!  

-bK

Thanks bK - I'm looking for a cab sim to process it right now.

was that dont shake me lucifer?

'Don't Shake Me Lucifer' by H.I.M. ?? No - great song though. Its the rhythm part to a song by my band....the song is called 'Stupid'.

[Jimmy-H]

A really great build again Rick!
I really like it.

And for the sound, It's very different compared to the Valvecaster.
I got a small tube amp (10 Watt).
And I can place two light bulbs of 5 Watt each in series with the speaker (with a switch).
They light up when I crank the amp .
But with those bulbs, I can get power tube distortion while the loudness is reasonable.
The sound I get is similar to the pentadrive.

Love to hear more of your clips.

[GREEN FUZ]

was that dont shake me lucifer?

I thought it was meant to be Anarchy in the UK  .

[frequencycentral]

A really great build again Rick!
I really like it.

And for the sound, It's very different compared to the Valvecaster.
I got a small tube amp (10 Watt).
And I can place two light bulbs of 5 Watt each in series with the speaker (with a switch).
They light up when I crank the amp .
But with those bulbs, I can get power tube distortion while the loudness is reasonable.
The sound I get is similar to the pentadrive.

Love to hear more of your clips.

Thanks Jimmy, I'll definately do some miced-up too.

Your light bulb thing is intriguing !! Light bulb mojo fuzz ??

I'm just completely fired up with this build - my own design !!! I think is sounds great - and the guts are my best yet too!

was that dont shake me lucifer?

I thought it was meant to be Anarchy in the UK  .

Hahaha! The song is kind of a 'homage'  - a bit like 'Anarchy' crossed with 'Virginia Plain'.......

[Jimmy-H]

I'm just completely fired up with this build - my own design !!!

Yeah that's really something to be proud of!!

I think is sounds great - and the guts are my best yet too!

That's for sure

[frequencycentral]

I've updated the schematic on page 1.

I added a 8K2 resistor between the gain pot and earth - maybe it should have been 10K though.

I added a Subcaster-like tone control.

I didn't change the volume pot in the end - it's still 100K.

Project complete! And on to the next submini tube pedal - what will it be ??

[doug deeper]

roky erikson and the aliens.

[MicFarlow77]

Hey Rick,

Super Nice Build! Very clean!

I was wondering what my next build might be.... looks like I found it.....

Thanks for sharing with the rest of us!

Mick

[mth5044]

That was really great. It sounds like a good digital distortion pedal through the sound card, so I can only imagine what it sounds like through an amp 

Very nice

Jimmy H - when you say it sounds very different to a valve caster, how do you mean? More/less gain? Brighter? Muddier? Do go on ^^

[frequencycentral]

Either this guy has HUGE HANDS or these 5672's are really small!!

[frequencycentral]

Just a bump to publish the final schematic. I've been deleting and re-uploading the schematic in Photobucket when I have made changes - but it occurs to me that 'cookies' might prevent the viewing unless you click 'refresh'.

[frequencycentral]

I just added another soundclip - it's the same clip but processed through this Cab Sim: http://www.hitsquad.com/smm/programs/CrunchDude/download/

I just used the default setting and added just a touch of NaturalVerb in Wavelab. It shows the pedal in a different light I think!

[frequencycentral]

If you have been following the "PentaBoost thread, you will have noted that Jasper Oosthoek has implemented an interesting idea for even more gain with his redesign of the "Red Star Drive", which I have now integrated into the "PentaBoost MkII".

I had to try this idea with the PentaDriver too - who doesn't want more gain???

So I just breadboarded the mod around the anode of the first stage, which results in the signal hitting the second stage even harder. Nice - a massive amount more saturation!

Fortunately, I left enough room on the board of my PentaDriver build to incorporate the mod, which consists of just one PNP transistor and three resistors.

For those of you who are wondering about a transistor been present in what is essentially an all tube circuit - don't worry, the transistor is not in the audio path, it is just there to allow the plate of the first stage to receive a higher voltage, rather than the significant voltage drop casued by the 100K anode resistor in the MkI schematic. The transistor addition gives the first stage an output equivalent to if it had been run at 22 volts - cool!

I've tried a bunch of different PNP transistors, all with good results:

Si: BC212, BC557C, 2n3906

Ge: 2n2000, 2n404, SFT353, GT403

What you do have to be aware of is that the Ge I tried required the 68K resistor to be replaced with a 27K. If in doubt use a trimpot in place of the 68K and dial in the 'sweet spot'

The PNP is also sensitive to changes in power supply voltage, and may have to be rebiased, so a good filtered/regulated wall wart is recommended. For the same reason, battery power is a no no - as the battery loses charge the biasing will go out.

I'll be updating the Red Star Drive thread with a MkII schematic soon, I have to breadboard and verify the mods first, and add a few extra ideas of my own.