NZGuitars.com

Sounds glorious!!

Well sounds great!

jeremyb wrote: ↑Sun Jan 02, 2022 10:08 am Sounds glorious!!

Thanks Jeremy.

Mosfet wrote: ↑Sun Jan 02, 2022 10:19 am Well sounds great!

Glad you liked it.

Wow, that sounds so awesome.

This is an amazing project to follow, thanks for taking the time and trouble to keep us all updated it really interesting.

Out of interest, what do you think the life expectancy of the bulb will be? is this classed as a consumable part or will it last the lifetime of the pedal?

Sounds amazing!! Well done you.

sty wrote: ↑Sun Jan 02, 2022 3:24 pm Wow, that sounds so awesome.

This is an amazing project to follow, thanks for taking the time and trouble to keep us all updated it really interesting.

Out of interest, what do you think the life expectancy of the bulb will be? is this classed as a consumable part or will it last the lifetime of the pedal?

Thanks. I'm glad you've been finding it interesting. I'm stoked with the results so far. And it has been a pleasure sharing it with everyone.

In regards to the life expectancy of the bulb, the one I have currently installed in the prototype is rated for 1000 hours. And I believe that rating is based on regular use. That figure in terms of a Uni-Vibe needs to be taken with a grain of salt, however, as the bulb itself isn't called upon to operate regularly per se.

The amount of current going through the bulb for the effect to sound as it should is severely restricted and therefore the brightness of the bulb isn't that high. In fact, you'd be surprised at how dim is actually is when everything is tuned correctly. Therefore, in regular operation, in a Uni-Vibe at least, the number is greatly inflated as the bulb is never stressed that much. By how much; I can't say. But from what I've read in regards to repairs performed on vintage Uni-Vibes, the bulb blowing is hardly ever the cause of the fault.

As with a lot of the things I create, I'm constantly tweaking and finding a better/more efficient way of doing things. In the case of the bulb, I've got a couple of others to try; one rated at 10,000 hours and the other at 16,000 hours so I will swap them out to see if there is any change in performance at some point. Most modern incarnations of the Uni-Vibe never turn the bulb off, even when the effect is bypassed. Doing so would mean there'd be a minor delay in response time until the bulb warms up and the modulation kicks in. I've explained the 'Cancel' mode of the original unit in previous posts and while it might take away from some of the original's mojo, most guitarists I'm guessing, probably want the effect to turn on as soon as the footswitch is pressed and might find the delay caused by the warm-up time quite annoying.

But with that said, I'm planning my own version of the 'Cancel' mode; again explained in a previous post that could be possibly be incorporated with the true bypass to extend the life of the bulb but we'll see.

~ Blake.

Miza wrote: ↑Sun Jan 02, 2022 4:54 pm Sounds amazing!! Well done you.

Thank you for the kind words.

Subscribed

Cdog wrote: ↑Sun Jan 02, 2022 5:54 pmSubscribed

One of the best resources I found while I was conducting my research for this build was Brad Burt's Classic Amplification website:

https://www.classicamplification.net

Especially the information on his Forum Vibe project:

https://www.classicamplification.net/fv/

Where he's essentially poured all his knowledge from working on vintage Uni-Vibes as well as circuit snippets for other experts in the field to create, what I think, is probably one of the best DIY Uni-Vibe projects out there today. See the link below:

https://musikding.de/docs/web/univibe-F ... -final.pdf

Brad also has a couple of interesting articles on his website; one regarding the History Of The Uni-Vibe:

https://www.classicamplification.net/info/uvh.html

And another entitled Fact or Funk, where he clears the air on some of the claims made by a couple of modern-day Uni-Vibe manufacturer's when comparing their Uni-Vibes to the original units.

https://www.classicamplification.net/info/ffwtf.html

I found this quite interesting, as let's face it, there is a lot of hype in the pedal world in regards to things like Magic diodes, New Old Stock (or NOS) Germanium transistors, and whatever else you can think of. So I found it a quite refreshing read.

***** WARNING: NERD ALERT *****
If you really want to go down the Uni-Vibe rabbit hole however, I'd suggest reading this paper from the Proceedings of the 22nd International Conference on Digital Audio Effects (or DAFx-19) held in Birmingham in the UK between September 2–6, 2019: https://www.dafx.de/paper-archive/2019/ ... per_31.pdf. However, it is not for the faint of heart.

One thing that caught my attention was the section on the light shield. Firstly, because I needed to find something to use as a light shield in my build. And secondly, I thought it would be a bit of an opportunity to have a bit of fun and conduct my own little experiment in regards to does a reflective light shield makes an actual difference to the sound of the Uni-Vibe when compared to a non-reflective surface.

In short, the main purpose of the light shield is to prevent any outside light source from polluting the LDRs and potentially altering how they react and ultimately altering the tone. I've seen plenty of things used as a light shield in other people DIY Uni-Vibe builds. Everything from period-correct folded aluminium sheet metal, to caps off soft-drink bottles, to insulation tape, to nothing at all. Heck! While experimenting with my mod for the MXR Phase 90, I used a small cardboard box! Which was, believe it or not, an upgrade over the black 2-litre ice cream container I was previously using.

Below: But needs musts.


Since the LDRs on the original Uni-Vibe lay flush against the PCB (the same approach I decided to take with my build), the theory goes that the shiny surface on the inside of the light shield helps reflect as much light as possible in the direction of the LDRs to maximise the quality and quantity of light they are exposures too. Some people often angle the LDRs or position them differently in an attempt to get around this issue. But being the purist that I am, I wanted to keep as close to the source material as possible.

My first issue, however, was finding something to use as a light shield in the first place. Cutting and folding aluminium sheet metal would be a hack job at best (for me anyway) as I wanted something that looked good. It was while visiting Bunnings that I came across these; 25mm square plastic chair tips. You know, the things you bung on the end of chair legs to prevent them from marking the floor etc. And absolutely perfect for my needs.



Available here for anyone interested:
https://www.bunnings.co.nz/tic-25mm-bla ... e_p4050054

The next problem was now to make it reflective. Again, others had lined the insides of their light shields with tin foil or reflective tape; again, something that didn't appeal to me. But it wasn't long until I stumbled across this; Molotow's Liquid Chrome paint.

Below: Molotow's Liquid Chrome paint.


And armed with some masking tape and my airbrush, I set to work.

Below: The un-masked light shield.


Below: The masked light shield.


Below: The painted light shield.


Oh. Shiny!


Below: Shiny vs. Non-shiny.


So the next question is, does it make any difference whatsoever? This post is long enough already so let me do some recording and I'll get back to you all again soon so you can be the judge. Stay tuned!

~ Blake.

The sound clip is awesome, seems you nailed it. Such an interesting thread too. Many thanks for sharing and for the added explanation for us duffers.

Agreed, this thread is fun. And thanks for the tip on your decent chrome paint. I bought a rattle can of 'chrome' paint recntly, which turned out to be a light silver metallic, not mirror finish chrome.

olegmcnoleg wrote: ↑Wed Jan 12, 2022 6:38 am The sound clip is awesome, seems you nailed it. Such an interesting thread too. Many thanks for sharing and for the added explanation for us duffers.

Thanks. I'm glad that you and others no doubt have found it of interest. It has helped me keep on track with the build instead of getting distracted by other things that I'm prone to doing.

Cdog wrote: ↑Wed Jan 12, 2022 7:03 am Agreed, this thread is fun. And thanks for the tip on your decent chrome paint. I bought a rattle can of 'chrome' paint recntly, which turned out to be a light silver metallic, not mirror finish chrome.

Thanks. The photo doesn't really do the finish on the paint justice. It is much more mirror-like in person. The paint you tried might have been the same paint I was originally going to try but luckily for me as it turned out, it was out of stock. This one:

https://www.bunnings.co.nz/rust-oleum-1 ... y_p1370100

I saw a few YouTube videos and brought the refill instead of a pen as the pen leaves streaks in the finish and I had an airbrush I used for hobby purposes anyway.

This is fascinating Blake. Your attention to detail is to be applauded! I'd love to try out a prototype once you get it completed.

Conway wrote: ↑Wed Jan 12, 2022 10:23 am This is fascinating Blake. Your attention to detail is to be applauded! I'd love to try out a prototype once you get it completed.

I'm glad I'm not the only one who thinks so. The enclosure for the prototype just arrived yesterday so that's my next task; boxing it up. Again, the enclosure is larger than what I intend on using for the actual production version as all the switching on the prototype is done by traditional footswitches and toggle switches rather than the planned microcontroller that will allow me to assign multiple functions to the same footswitch. Cutting everything down to just two soft-touch footswitches instead of the three traditional footswitches and two toggle switches on the prototype. A few things have evolved during this whole process that I will explain in more detail once I completed the prototype. That was always going to be the last piece of the puzzle; the switching, after everything else was to my liking.

If you're keen; you're more than welcome to try it out. I'd really appreciate the feedback from the second set of ears. As well as from a functional point of view too.