VHT - Valvulator

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
donegone
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Post by donegone »

Who supplied you with the replacement transformer for the Valvulator.? I am looking to replace a damaged one I have now.

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theehman
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Post by theehman »

donegone wrote:Who supplied you with the replacement transformer for the Valvulator.? I am looking to replace a damaged one I have now.
I got it from VHT. Give them a call.
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theehman
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Post by theehman »

Here's the completed schematic with voltages and the pedal power supplies.
Attachments
VHTValvulator.jpg
Ron Neely II
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Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

brewdude
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Post by brewdude »

This is my first post on this forum.
I was led here through a google search for VHT Valvulator.
I have owned one for a long time but not used in many years.
I recently plugged into it, then a booster pedal, then a reverb, then an 18 watt Lite 2B and a 1x12 cab.
The Valvulator seemed to add noise and every thing seemed much better without it.

I have taken a look at the photo's and schematic. Thanks for posting.
Do you have an opinion about the Valvulator?
Have you attempted any modifications?

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theehman
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Post by theehman »

brewdude wrote:This is my first post on this forum.
I was led here through a google search for VHT Valvulator.
I have owned one for a long time but not used in many years.
I recently plugged into it, then a booster pedal, then a reverb, then an 18 watt Lite 2B and a 1x12 cab.
The Valvulator seemed to add noise and every thing seemed much better without it.

I have taken a look at the photo's and schematic. Thanks for posting.
Do you have an opinion about the Valvulator?
Have you attempted any modifications?
Maybe it needs a new tube? I haven't noticed any noise with mine. The only mod I've made is to replace the 12v regulator with a 9v one.
Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

brewdude
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Post by brewdude »

thanks.

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Post by Hotrats »

just as a curiosity can you post the voltage across the winding that feeds the filament,
with and without the tube in circuit ?
also, what is the exact filament voltage with the tube in circuit ?

ajmc0116
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Post by ajmc0116 »

Hi, does anybody have a PCB layout that i could use to make a board? i think this might be a fun little project :)

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Post by brewdude »

ajmc0116 wrote:Hi, does anybody have a PCB layout that i could use to make a board? i think this might be a fun little project :)
I don't think this is exactly what you are looking for, but this is what I have.
Attachments
VHTValvulator.jpg
VHTcomp.jpg
VHTmerge.jpg
VHTboard.jpg

Vicci
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Post by Vicci »

Hi,
i'm newbie. I know this post is a little bit old but I'm beginning to make StompBoxes and I've read that the bufffers are the easiest pedal to make (also booster). I've saved schematics and photos but I dont undestand the schematic without tranformers. What voltage use? 9V DC like others pedal? Explain to me please :)
Thanks a lot!

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Post by oldmica »

Any guess (or measured value) for C2M? I know, holy necro, Batman! :)

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theehman
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Post by theehman »

oldmica wrote:Any guess (or measured value) for C2M? I know, holy necro, Batman! :)
it wasn't placed on the pcb.
Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

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Post by oldmica »

Ahh, got it! Thought possibly that meant the part was there, but not the value. Thanks very much!

Fwiw, when I build this circuit, I'll try a few different small value HV caps in there, just to see what they sound like. Also will wire it up to be able to try a 12DW7, with the 'U' section as the cathode follower.

It looks pretty interesting. I've seen a bunch of gain-into-cathode follower circuits & this one is cool and different.

Someone over at hamerfanclub.com mentioned running one of these into a multieffects unit, with good results.

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Post by oldmica »

Tone Press -> Valvulator 1 -> SansAmp PSA-1 -> TC Electronics (can't make out the model) -> Power Engine

https://www.hamerfanclub.com/forums/top ... e-for-ass/

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Post by shakti »

The thread that refused to die...

I have owned one of these since 2000 or 2001 and absolutely love it. A few years ago I tried to simplify and stupidly sold it, only to realize I miss what it did to my tone. So I searched out another used one which I bought about 3 years ago. It's not a particularly neutral sounding buffer, but it's by far the best feeling and most "alive" sounding buffer I've tried.

But lately it's not sounding its own self. I figured the tube needed replacing, but I've tried just about every tube in my stash which includes most of the most desired old production tubes, but the problem remains no matter which tube I have tried.

The symptoms that I am experiencing with it are:
- slight pop or tick that is heard occasionally in the background
- when I unplug the guitar from the Valvulator, or the Valvulator from the amp, a very noticeable and rather loud pop is heard from the amp. This never happened before. I usually have it set up in a Lehle D.Loop true bypass looper, and when switching it in and out I also get a veery loud pop which didn't happen before.
- the buffer is sounding just a little bit dull and still slightly harsh. It's quite subtle actually, but it is not sounding right. With a clean amp setting it's not necessarily very noticeable, but the louder and more distorted I set the amp, the more obvious it becomes that the unit is actually not delivering unity gain. It seems to be buffering, as it does offset some of the high end loss of long cable runs, but it also cuts the gain very slightly. With the D.Loop it is very easy to test this A/B, and it is very clear. The D.Loop even has a built in switchable buffer which can be set for unity gain. I always preferred the Valvulator to this buffer for it vibrancv and superior feel, and it always seemed to eeever so slightly boost above unity gain (maybe it was just the harmonics of the tube making it seem that way), but now it is clearly duller and not sounding right.

I tried dismantling the Valvulator to inspect for any signs of failing components or bad solder joints, but could not see anything wrong.

Any hints where I should search next? Slight popping/ticking background noise, loud pop when plugging/unplugging or switching, slight loss of output. I am thinking perhaps something is leaking DC, but I am a novice when it comes to actually locating the faulty part. I have lots of amp building experience but with limited tech know-how, and little experience working on PCBs.

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Post by shakti »

Sorry, realize I should probably ask this in the troubleshooting section. However if the schematic gives you a hint where I might start looking, feel free to shout out.

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Post by shakti »

I found out that I have about 1.5 VDC across the output jack(s). Nothing across the input jack. seems to me that something is leaking DC, perhaps one of the two 10uF caps at the output? It seemed to sound slightly better today but still not as good as it used to, and still the loud popping. If the cap(s) are going bad, perhaps that could present itself like that, somewhat intermittently?

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Post by FiveseveN »

Yes, swapping the output caps is a good bet under the circumstances.
Ignorance more frequently begets confidence than does knowledge. (Charles Darwin)

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Post by mnemonic »

At one point mine started making popping and crackling noises during power-up, then they were always there but low level, then suddenly very loud popping and cracking that made it unusable. The ground lift switch also did weird things around that time.

It ended up being R9m on the schematic above, I couldn’t get a solid reading on its value in-circuit and after pulling it out it was totally dead with no continuity. Replaced it and it’s been fine since.

Fryette email support was pretty helpful and replied quickly to me, but I hear they can be hit-or-miss sometimes.

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Post by shakti »

Thanks, that's also a thing to look into. I will have to order some parts first. I really want to get it working properly again; despite the problems (Power supply can induce hum in nearby pedals, it's not really transparent, it's bulky for a buffer etc) I like what it does so much that I want it available, albeit not all the time.

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