And so we returned to the original question: if you know experts like that, let me know! Thanks!

 

Ah right yes. To answer your question no I don't know an electonics expert who could adivise or fix the problems that you have with most of your guitar pedals.
If non of the advise here fits the issue your having with multiple pedals I wish you Good luck,

 

ive built some pedals over the years, but my main focus is circuit bending and diy synth. I do have a basic understanding of circuit flow, schematics, design etc. In this case, i highly doubt its all of your pedals that are faulty. If volume down to zero on the guitar is helping the issue, have you tried just putting a simple gain pedal as first in the chain?

 

Sounds like a design feature to me.

If the pedal only clips on above 75% of a standard guitars output, it gives you the ability to to add a slight greener pedal/clipping distortion effect just by turning the volume knob on the guitar.

If they've done what I think they have then the compressor should also adjust the output volume so the change is less noticable other then the distortion.

The real answer is as you guessed

Unless you have at least a advanced level of understanding of electronics, no expert will be able to talk you though disassembling and testing the pedal through a forum.

 

The audiophile expert has spoken. Why don't you just ask the high end audio guys around you? I'm servicing vintage Hammond, Leslie and other tube amplifiers for many years, and there are always some "clients from hell" who know everything better. So again: good luck.

 

Running 18v into pedals meant to take 9v is probably why your pedals sound like crap if you haven't already fried them..

 

maybe one of the rare synth servicing and retail shops is in your area .

man i miss dedicated service/retailers for all kinds of stuff ,decline even begun in 90ies.
...alone the smell of all that material when you came into the shop .

partly agreed but its not impossible ....but def not here rather in electronics tech nerd forum ,to much time consuming even just for clearing tool set and knowledge level

 

No, actually the opposite. It was the Demeter technician at the support who suggested that in case I have that distortion problem I should power it on 18V. It is a known trick for compressors, for those that can withstand that current. The Wampler Ego compressor, for example, and some others are listing this option in their specs as well. Demeter not, but it revealed it can handle that current. And it helps in case of compressors, raises the headroom.

 

We are actually doing that in another forum. With the Optivalve. I have already deassembled it according to the directions and doing measurements. We already found some troublesome places on the circuit.

But I'd prefer taking it to en expert who does know about the operation of these.

 

It's voltage, not current. And be aware of those generalized "tricks" you can find anywhere, it totally depends on the circuit! Don't do it if you don't have the schematics and have no clue about electronics. Many simple circuits based on op amps are fine, because these can be powered by up to +-18 volts, so 18 volts (+-9) are ok. But any discrete transistor stages that are calculated for a specific supply voltage are then running fully out of specs which can lead to unwanted behaviour and sound or even damage.

Even more complicated are any pedals using tubes. They have to internally generate and deliver the correct heating and plate voltages to the tube, about 6.3 volts heating and 200 to 300 volts plate. High voltage is extremely dangerous, so don't mess around with it if you don't know what you are doing!

 

That's also an "audiophile" phenomena, finding "optimizations" to circuits without understanding them.

 

I didn't know you are more clever and better informed of these pedals than their maker. :O So you mean next time I had better ask you about solutions not them?

 

It is enough if those understand the circuit who direct me. If the problem can be solved, I won't be upset about that. I am only upset when those give me advices who think they know more about a circuit than their maker. Being more expert than the expert.

By the way, beyond your expertise, any contributions to the original question, or you will miss that this time again, as usual? You see, those are the things I would like you to be expert instead: answer the original question. Those things you often miss.

 

did you ever see an hammond from the inside , more expert on analog circuits isnt possible i guess and the dudes able to do this are rare .im sure he could fix or at least proper analyze it if he had in his workshop but not with that information you brought up here ,and when you in contact with your so called maker why any questions still open .man he just did few sidenotes from experiences in this realm thats it and you take it personal wtf. i do my bets on that this guy is the most expert you will find if not finding a dedicated active subforum for tube pedals .

 

It would be nice if you would write the product in question with the full name. You also do not describe the problem correctly. Do you have an audio sample? EDIT: I have now found the video.

You don't have to be an electronics expert to solve some guitar pedal problems either. First, write to the manufacturer and describe your problem. Since you haven't received an answer to your problem for years, I would suggest you buy a new pedal from a well-known manufacturer (Roland/Boss for example) where you can also get support. www.sound-service.eu/en/gurus-optivalve-mkii

Unscrew it and check whether the capacitors have leaked or burst, take a few photos of the inside. Use new cables and test for loose connections. Check the inside for damage. Many electronic devices do not have an infinite lifespan, so consider buying a new one.

I don't think it's broken at all, the user is trying to play clean sounds but it's a tube compressor, here is a copied text:

The Gurus Optivalve mkII is an analog tube compressor that is based on the most popular vintage studio units in terms of sound and therefore offers a particularly fat and organic sound. The compact effects pedal, whose circuitry is completely analog, offers controls for input, output, ratio and tone to adjust the sound, while the six-digit display visualizes the work of the compressor.

Maybe you should familiarize yourself with the instruction manual.

Spoiler: Review:

Review:

Optical compressors are not incredibly fast and precise tools, they tend to respond a little slowly and are therefore ideal for "rounding things out". The strength of the compression can be adjusted using the control labeled Ratio.

This ranges from zero to virtually infinity, so it offers an enormous range. In the "0" position, the pedal functions more or less like a tube preamp, the degree of saturation of which is determined by the input control. In the appropriate position, a slight overdrive is even possible, which of course also creates a type of compression.

When the ratio is increased, the optical compression starts, which is signaled by a green UV meter lighting up. However, this only reaches full swing when the compression is more than noticeable; before that, you can hardly hear more than a glow and the display is little more than a guess. The threshold value of the compression is also set using the input gain, but there is no control for this. For only light compression, a low input gain and a fairly high output gain are needed to achieve the desired volume. The compression itself is typical for an opto-comp. The relatively slow response means that the signal retains the transient and thus the pressure as much as possible, while the slow, non-linear release ensures a relaxed rounding off of the rest of the sound.

This means that basses immediately sound pleasantly thick and powerful. With sufficiently strong settings, the sound naturally also starts to pump, but even that in a way that can be used very musically in certain scenarios. Palm mutes with the treble control turned down, for example, get a wonderfully tough character. Just try it out.

https://www.gitarrebass.de/equipment/in-die-roehre-schauen-gurus-optivalve-mkii-kompressor-im-test/

 

Last edited: Dec 19, 2024 at 1:26 PM

I never said that, but at least I can read schematics and know how tube or transistor circuits work.

 

The original question simlpy can't be answered as easy as that because distortion or THD is not "there or not", especially with tubes that don't clip hard as transistors it depends on harmonics and how strong they are, at what frequencies and what levels. You wrote that with single coils "distortion is gone", which only means that their levels are low enough for you to have the impression of a clean signal. Analyzing and modifying tube circuits is nothing someone can explain in some comments on a forum to someone who doesn't know the culprits of this technology and has no equipment for that.

I would never recommend someone without any knowledge to disassemble and measure something in tube circuits. At least you will notice it if you have "found" any high voltage part.

And about "knowing more about the circuit than their maker", most service technicians know this too well. Mostly with people who read about fancy modifications and "optimize" circuits by exchanging parts without knowing what they do and to what side effects different parts specs can lead.

 

I suggest @sono start making music and don't get lost in the details.

Gurus Optivalve MKII Compressor Review -->
www.compressorpedalreviews.com/post/gurus-optivalve-mkii-compressor-review

Gurus Amps Sexydrive MkII

How it sounds in BELLA "ROCKIN" ITALIA

 

Last edited: Dec 19, 2024 at 1:37 PM

There's no way that tube in that pedal is being fed 200 to 300 volts, it's most definitely a starved plate and will sound like less like good tube harmonic distortion and more as a screech owl calling out for a mate under the light of a harvest moon.

 

You never know without the schematics. I'm not familiar with these "modern" approaches, only vintage designs. But I heard that some developers indeed use SMPS for high voltage. Without being sure you don't want to "test" it yourself by touching.