I would like some help designing a treble boost/tube overdrive...

[Brossman]

So, I've recently picked up a pair of Sonotone AF-5977a Triode tubes.  These are apparently equivilant to 6AK4 tubes...

I've also managed to get a pair of Raytheon CK6612 RF Pentode tubes.

I have datasheets on these tubes, so I can tell you anything you need to know, but I don't know how they will work, or whether they will work for this kind of circuit.

I don't care if it's ever been done - I want to do it anyway.  I don't know if I should use 2 tubes, all 4, put them in series, etc.

What about using two circuits in one - one uses tubes, and at the flip of a switch, use transitors?

I have scrounged up a number of old parts from my father's old HAM radio operations, so I have a good collection of some basic parts to work with.  I think some of it's some good stuff, too; I've ID'd 5 Germanium 34a diodes.

Then comes the idea to boost the treble, or I guess, roll off the bass?  Lots of fuzz/overdrive tends to get too muddy with humbuckers, but I can't get away from that nice and fat High output...

ANybody have any ideas?

Thanks,

- Britt R.

[anchovie]

Is the clean boost mentioned in your sig the only thing you've built so far? I'm concerned this is way over your experience level. There's plenty of stuff on the interweb to tell you about how tube voltages can kill you. It would also be helpful to know how much experience you've had specifically with tubes.

I don't know how many tubes you need to use either - you haven't mentioned how you hope this will sound. Blues? Death Metal? Don't worry about switching between two boards until you've got a really good sounding tube circuit and a really good sounding transistor circuit that you feel you'd like to switch between. Likewise, don't worry about a treble booster until you've got a circuit that would benefit from having a treble booster.

It would probably be best if you uploaded those datasheets somewhere and posted the links.

Hope none of that came across as harsh - just don't want to see someone get electrocuted because they had an exciting idea!

[frequencycentral]

Did you want to do something at high voltage or low voltage?

5977: http://frank.pocnet.net/sheets/127/5/5977.pdf

6612: http://frank.pocnet.net/sheets/138/6/6612.pdf

[Brossman]

I haven't really any experience with tubes, to be honest.

It is my understanding, though, that these submini pentodes and triodes can be run at lower voltages??

As far as the tone goes, I want some that gives a crispy, overdriven tone (maybe with a natural compression), with bitey attack.  That's about as straight forward as I can think...

[Brossman]

Oh, and thanks to FrequencyCentral for posting those datasheets!

[frequencycentral]

Have a look at the link in my sig for 'Pentadriver' that you could sub the 6612 into, in place of the 5672 I used.

For a good start with tubes you couldn't do better than a Valvecaster, which you should be able to adapt your two 5977 into:

http://www.diystompboxes.com/smfforum/index.php?topic=63479.0

Neither might be quite what you're looking for but will give you a starting point.

[Renegadrian]

I think your idea can be easily turned to reality...Dunno much about that RF pentode, but maybe can be used as other submini pentodes...As its max voltage rating is so low, I bet it'd sound good at 12V too...You may want to look at other pentodes schems, like Rick's or my WEREWOLF.
As for the triodes, maybe using two can get you a decent booster overdrive - you may want to start with the valvecaster circuit, or other double triode circuits of your choice - next a voltage multiplier could be a nice add-on.
But yeah, who needs high voltage?! 

[Brossman]

So, how exactly does the voltage being run through the circuit affect the signal? 

Does it change the properties of all the components, or does it only affect the tubes? 

Either way, how does running at low vs. high voltages affect the tone (or maybe I should say 'tone quality')

Thanks,

- Britt

[Brossman]

Rick, for the Valve caster plan, should I use Matsumin's actual schematic (http://www.matsumin.net/diy/jisaku2/Valve_Caster/Valve_Caster_10.BMP), or should I use the one at the link you gave me?

Dano12 said he used different caps than the original and that his site no longer exists (it's only moved)...

Again, thanks,

- Britt

[panterafanatic]

So, how exactly does the voltage being run through the circuit affect the signal? 

Does it change the properties of all the components, or does it only affect the tubes? 

Either way, how does running at low vs. high voltages affect the tone (or maybe I should say 'tone quality')

Thanks,

- Britt

absolutely yes. some circuits sound better going to the higher voltages and some sound worse. you'd have to test for yourself to se which you'd prefer

[Renegadrian]

Yeah, there are no shortcuts here, so if you want to make something quite good with them, you just have to experiment a lot - results will magicly come!!! Now take your breadboard!!! 

[Brossman]

I really appreciate everyone's input!  Thanks guys, you're really helping me out here.  I really don't know squat about this stuff (scientifically, those equations blow my brain), but I'm doing my damndest to learn.

I'll let you know what plans I decide to pursue, once I figure it out, lol    Thanks again!

[Renegadrian]

Bross, I'll tell you my experience with my original design, the TUBE STAR (12AT7 high gain pedal)
I just started messing around with a MESA BOOGIE circuit, breadboard it, change/swap/add/remove components, and finally got a nice high gain circuit that's quite different (only a little of the starting point remained).
So yeah, that could be a starting point and also a great learning experience (while some cats go with theory first, I prefer the practical approach...)
I am sure you'll find the way that suits you best. Let us know your results then!!! 

[Brossman]

Okay, so, is it a crime against everything I'm doing here to not own a breadboard?  Or even worse, not understand how they work?

I know what they're designed for, but I've never used one .  Well, not that I remember (maybe once in a shop class in middle school [long time ago...]).  In fact, I have a set of bent connector wires of various sizes/colors that I believe to be for breadboarding...

[jacobyjd]

Some guys tend to design circuits straight on paper. These same people generally know more than you or I ever will, and have enough theory knowledge to KNOW that something will at least do what they want it to, so they don't spend as much time on the breadboard--if they do, it's usually for working out specific problems that you can't explicitly see on paper.

That's just one example, of course.

However, people with less knowledge generally can breadboard a circuit with specific ideas in mind, then experiment and research, research and experiment until they get the results they were looking for. That's generally what I do with my breadboard.

I don't know how much of a crime it is that you don't own one :-P However, let me put it this way: even circuits I build on PCB get attached to my breadboard for all off-board connections during the test/debug stage. I've found it to be unbelievably useful in that sense.

Either way, you can get by without one, but hey, they're cheap! Find a short length of wooden board, screw your breadboard down to it, slap a piece of metal angle on the board, drill some holes, add some jacks and a place to hold your battery, maybe a built-in bypass switch, and you've got a pretty comprehensive station to try out any circuit you have parts for

I think mine cost me $10 to make.

[frequencycentral]

I got by without one for years. But building a 'new idea' directly onto perf and hoping it works, and debugging/redesigning said already-soldered circuit is frustrating compared to using a breadboard where you can just pop components in and out, and start again completely.

If you just want to build pedals from existing schematics = no breadboard required. The title of this thread is I would like some help designing a treble boost/tube overdrive..., the minute you say 'designing' it's breadboard time.

My breadboards are my favourite toys. They can be anything you want them to be. Add a breakout box with input, output, DC socket, a stompswitch and a LED and you can use the circuit it real life with other gear.

Here's some ideas: http://www.diystompboxes.com/smfforum/index.php?topic=69404.0

[Brossman]

Would I need to use a transformer in my circuit for these tube pedals, whether running 6.3V or 12V?  If so, what is a cost-effective, yet reliable (and space saving) choice?

Thanks!

[frequencycentral]

You recommended that I substitute my 5977 subminis for the 12au7s in the valvecaster circuit.  I was wondering if I would have to make any adjustments of parts (res. values, caps, etc) in order for it to work correctly?  Or is the 5977 okay to use as a direct swap out?

If I do make any adjustments, how will I know what to change, and by how much?

Would I need to use a transformer in my circuit for these tube pedals, whether running 6.3V or 12V?  If so, what is a cost-effective, yet reliable (and space saving) choice?

The link I provided to the 5977 data sheet seems to be down ATM. But assuming it's a medium mu triode I think you could try subbing it into the Valvecaster circuit without any component changes. Run it at 12 volts from a regulated wallwart. If you build the circuit point to point onto the back of the tube sockets (or onto breadboard) you can always change component values later. All the caps should certainly be fine if you follow the Valvecaster schematic, the only things that may need changing are the two plate resistors, the 220K and the 100K. You'll need to compare the 12AU7 data sheet with the 5977 data sheet to figure which pin corresponds to which.

[Gus]

Something to keep in mind about a tube treble boost.  Part of the RM and other BJT based treble boosts is the low input resistance that loads the pickup(s).

A tube grid to ground resistor can be reduced to the 22K etc from 1meg that you often see on tube guitar preamp inputs.

[Brossman]

The link I provided to the 5977 data sheet seems to be down ATM. But assuming it's a medium mu triode I think you could try subbing it into the Valvecaster circuit without any component changes. Run it at 12 volts from a regulated wallwart. If you build the circuit point to point onto the back of the tube sockets (or onto breadboard) you can always change component values later. All the caps should certainly be fine if you follow the Valvecaster schematic, the only things that may need changing are the two plate resistors, the 220K and the 100K. You'll need to compare the 12AU7 data sheet with the 5977 data sheet to figure which pin corresponds to which.

Okay, I tried to compare datasheets to check values, and I don't understand part of it.  My 5977 is a single triode, but the 12AU7 is a twin triode, so all the datasheets have two sets of information...Does this change whether or not these tubes are interchangable?

Also, all of the data I've read on the 5977 seems to be giving readings at 6.3V.  Am I correct in assuming then, that it is meant to be run at 6.3V (or on a 9V circuit)?  And that I do not need to use a voltage doubler?

This just made me think of something...Is the Valvcaster circuit running on 12V because the tubes in the original design are twin triode tubes?  This leads me to believe that the circuit would be similar, yes, but not identical since the 5977's are only single triode tubes...

Thanks,

- Britt R.