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Hi is there v-twin guts ?

thanks

Maybe you can write the next time the manufacturer too in the headline ?

I assume that you could mean the Mesa-Boogie V-Twin preamp. If you are looking for a schematic too, this can be found here:

http://www.tubefreak.com/v-twinp.gif

analogguru

Thanks analogguru, yes, i mean mesa-boogie v-twin. I have the schematics, but I like to see how it's made inside. Some pictures inside.
thanks

I had one, I was underwhelmed by its tone. Didn't seem to have as much gain as I expected, and kind of loose sounding on the bottom end. The headphone amp out sounded pretty buzzy.

Are the tubes in there so you can see where the knobs are when playing on a dimly lit stage?

vanessa wrote:Are the tubes in there so you can see where the knobs are when playing on a dimly lit stage?

Even the tubes don't glow so bright. They stick an LED in there by the tubes to kind of make the tubes look like they're lighting up.

Not one of my favourite sounding or looking pedals
bajaman

bajaman wrote:Not one of my favourite sounding or looking pedals
bajaman

Yeah, but I like to see a topology of this pedal

okay - next time one comes in the workshop, i will take some photos of the guts for you
bajaman

thanks Baja

Does anybody has the original V-twin schematic?
I think this famous internet schematic is not correct.

I think the numbers of the JFET switches are shuffled, and it's quite difficult to sort as there are some oldschool diode logic and seveal inversions in the switching circuit, as well as LEDs for display and LEDs for vactrols.
I guess Q1, Q4, /Q3 and maybe /Q4 deal with bypass ; Q2, Q5, D6 -> R7, /Q8 and /D27 -> R38 deal with channel switching ; and Q6 deal with the "blues" setting.

'/' means 'NOT', of course.

Here are some gutshots of the Mesa/Boogie V-Twin preamp pedal if anyone cares




Higher res:
http://i34.tinypic.com/jl2ej6.jpg
http://i38.tinypic.com/2py17hc.jpg

Thanks Duke Lion..

merged with existing topic.

too much bullcrap for a 2 tube pedal. Can make something much simpler and sound real good.

You're probably right.
I wouldn't buy one for what they go for on ebay, but I got a killer deal on mine. I'll keep it until something better comes along, and then sell it and make a huge profit

Duke Lion wrote:You're probably right.
I wouldn't buy one for what they go for on ebay, but I got a killer deal on mine. I'll keep it until something better comes along, and then sell it and make a huge profit

The Kingsley Jester might be the ticket for "something better comes along" but if you are DIY, even the EH English Muff'n pedals fits the bill. It's not rare, and still available new, even, if you're so inclined. You might be able to buy two with the sale of a V-Twin. That V-Twin always looks pretty rugged, however...

Anyhow, used, including power supply and two tubes, it wouldn't be hard to get one for around $100-120 or less, depending on your source. Ebay might even be cheaper than that. It's a basic 3 stage tube-based preamp run on high voltages, plus a cathode follower stage (think buffer) followed 3 band tone stack. It won't do 4 stages, but 3 gain stages can get pretty heavy! Personally I modded mine for far less gain, actually. The schem can be found linked on this site. If you look you'll see it's a little wacky in parts, but easily modified and simplified with some snips and soldering, to taste.

Consulting other schematics for amps, tube pedals and other projects, a lot can be done to get different sounds. Also, most of your 9v pedal parts will work, as there are only a few components that need to withstand high voltages (coupling caps off the plates and higher wattages needed for plate resistors). Modding it is not dissimilar to the principles of working with FETs (and visa versa), actually, if you're a tweaker/breadboarder like I am. You'll need to following the additional basic steps to drain the high voltage, which can be as simple as getting as holding a higher wattage (1W+ is ideal), smaller value (1K) resistor with insulated pliers and bridging it across the large filter caps, then using your DMM to make sure they've drained, and you're safe.

I found it a great way to get into tubes, and likewise, it satisfied most of my curiosity in tweaking for the 'ultimate tube pedal sound.' I have gotten a sound I'm really impressed with so far, but it's simultaneously confirmed how happy I am with FET stuff as well, which can yield equally great and somewhat similar sounds if tweaked intelligently.

Anyhow, feel free to PM me, or post on that thread if you have interest or questions about modding one.

I have the gut shots of the Jester and wow..Im impressed. I think thats a great way to go, build a fendery/marshally style tube pre in a box.

Im going the extra step of using a 3rd tube, a 12BH7 as the output and then using local feedback with 2 controls for that part. I found a cool idea in Dan Torres' book but I lost that book long ago.