Kingsley Bard - great tube bias tremolo pedal

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vintagecharlie
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Post by vintagecharlie »

Hi folks,

has anyone more info on the Kingsley Bard? I am wondering, if it is a design based on others or, if this is a new circuit of sorts? I could not find a schematic, but here is a gut shot that reveals at least something - maybe some one knowledgeable can make a good educated guess, what this might be based on and maybe it is possible to get a schematic together?

A demo can be found here:

Pedalwise, at least to my ear, it blows everything else away, including the bias trem mode of the Strymon Flint, EH Wiggler, which sounds very choppy despite the tubes, and some other tremolo pedals with tubes that either are not as intense or that do not have that smooth and swampy asymmetric sine wave. The tube reverb/tremolo units like the Weber Torevibe seem to have a very similar sound, but nothing else i''ve found in the pedal form comes close to this smooth and swampy tone.

Thanks for any input, guys!

VintageCharlie
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Post by snofla1900 »

Pedalwise, at least to my ear, it blows everything else away,

It sounds good but I don't agree with you : my Tremulus Line sounds just as good in my humble opinion.

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Post by vintagecharlie »

Yes, i should have stressed that, of course, in my personal opinion, the Kingsley Bard is better for the bias trem sound than any other IC, transistor or opto-coupler trem. As this is always a purely subjective preference thing. The Bard can do one thing, but it can do it almost or just as good as the tube reverb units with built in bias tremolo. To MY ear, no other design reaches the same swampy, thick and extremely smooth, while also very deep effect. The clips of tremulus lune that i've heard don't seem to show it as being able to have that exact sound. But, yeah, i have no first hand experience with the Lune and i am sure it is a great pedal too.

There is a transistor in the Bard circuit, however i do not know, what exactly it does - if it is in the LFO, or if the LFO is fulfilled by one half of the 12ax7. Also, what i like about the design - it seems to be a fairly simple build. By the looks of it, there is a power supply and a voltage controller instead of a transformer - is this possible to achieve 275v DC with that kind of approach, or do i just don't see the transformer?

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Post by FuzzMonkey »

I've been interested in the power supply as well. It looks like some sort of DC-DC converter of some sort. Possibly third-party.

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Post by vintagecharlie »

FuzzMonkey wrote:I've been interested in the power supply as well. It looks like some sort of DC-DC converter of some sort. Possibly third-party.
Exactly, i realised this yesterday, as i noticed that the Squire and some other pedals seem to use the same PSU pcb board, sometimes without some components. It DOES look like a 3rd party unit, i found a pic with the product number - will post it later today. I think it was PS-T1 REV 2 or something like that.

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Post by vintagecharlie »

Intripped wrote:I think it's something like this:
https://www.tube-town.net/ttstore/Kits/ ... anguage=en
Thanks for the link! Yes, indeed it does look like something along those lines. The Bard needs a 6.3 VDC line and a 275VDC line.

PS-T1 REV2 was correct for the PCB number:

https://lh5.googleusercontent.com/-zK9_ ... 142731.jpg

But i had no luck finding the supplier so far. Neuther have i found better pics of the power supply part yet.

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Post by FuzzMonkey »

Intripped wrote:I think it's something like this:
https://www.tube-town.net/ttstore/Kits/ ... anguage=en
Only 220VDC however.

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Post by ppluis0 »

Hi folks,

Just search the web asking for "nixie power supply" and looks for a simple design.

Here is a link for one of these examples: http://www.instructables.com/id/Nixie-Tube-HV-Driver/

Cheers,
Jose

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Post by Intripped »

We are on the right path, here's another one that can go up to 300V, but I've not found anything about current capabilities (I've just read very quickly, probably I missed it)

http://www.instructables.com/id/High-Vo ... alve-Tube/

PS:
And another one

http://www.instructables.com/id/Adjusta ... ith-Submi/

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Post by FuzzMonkey »

This is from the Grind Customs FX website:

http://www.grindcustomsfx.com/product/g ... ponent-kit

Used in conjunction with their STM800 project:

http://www.grindcustomsfx.com/product/gcfx-stm800

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Post by vintagecharlie »

Here is a closer look at the PSU Kingsley uses for Bard, Squire and others. For the Bard the V3 spot is certainly populated.

What is that WE (Wurth Elektronik?) 221 part - an inductor?

Reverse UR logo means - UL RECOGNIZED COMPONENT MARK. No idea, if the digital watch style numbers 1313 might be a brand name of the 3rd party psu.
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Post by deltafred »

vintagecharlie wrote:What is that WE (Wurth Elektronik?) 221 part - an inductor?
Pretty sure it is an inductor, 220 mH.
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Post by vintagecharlie »

So the PCB/model Nr. seems to be PS-T1 REV2.

here are the other markings on the board - maybe something gives away the supplier.

As i found out, the reverse UR logo means it's a UL RECOGNIZED COMPONENT MARK

Anyone recognizes the logo beneath the UR sign?

R(A?)Z-01A
94v-0
E322597? (serial Nr.?)

1313 (brand name maybe?)

Either way, it should be capable of converting 9 VDC up to 275 VDC. The power requirements for the pedal are listed as 550mA. I guess that this probably includes some reserve, so the actual mA rating for the PSU itself might be lower, but about 500-600mA might be what is needed.

If anyone knows of good alternatives or can identify, which PSU is used exactly, i'd be very grateful.

I'd be ready to just buy the pedal, but it is simply unobtainable and the waiting list is about 2 years by now. Also, aside from the high voltage involved and the PSU itself, this looks like a simple build with few parts.
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Post by vintagecharlie »

Some notes on components that can be identified by this pic:

4x Mallory 150 .022uF@630v caps
1x 0.15uF (film?) cap

1x 12k
1x 1,5k
1x 220k
1x 100k
1x 680k

1x transistor that i have not identified yet

3m pot

More pics would be needed to identify the few remaining components (apart from the PSU). Maybe someone with deeper understanding of this sort of designs might be able to deduce a schematic, but maybe that is a long shot, i don't know.
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bard components.jpg

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Post by ppluis0 »

About the currents involved:

The heater of a 12AX7 draws 150 mA @ 12.6 Vdc, or 300 mA if the socket are wired to be connected to 6.3 Vdc.

The HV supply of both sections of this tube barely drawn more than 1 mA each, so employ ANY step up converter similar to the already mentioned previously will work.

Cheers,
Jose

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Post by vintagecharlie »

Thanks for all the input guys!

A good soul sent me this piece of information:

"Look at the vibrochamp and remove the first input stage from the audio path and the buffer from the output of the oscillator. The rest should be really similar. Well, and you need a 250V PSU."

In fact, in his demo Simon actually mentions the Princeton and Vibrochamp as particularily nice sounding examples of tube bias tremolo. So looks like it is a pedal version of the Vibrochamp tremolo.

Unfortunately i understand too little of electronics to actually profit from this valuable piece of info. If anyone with the know-how could help us out with this, i think this might turn out into a nice little project.

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Post by Dingleberry »

Took a closer at the vintagecharlie's pic and the component marked "wire wound resistor?".
Little help with Ms Paint and I can pretty much confirm that component is a 10 µH inductor made by Fastron. (Inductor Axial lead 10 µH 0.105 Ω 3 A Fastron)
I attached a picture to confirm my conclusions (could not find a pic of Fastron 10 µH inductor, so I used 680 µH as an example)
-T
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Simplify before you amplify.

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Post by vintagecharlie »

Dingleberry wrote: Little help with Ms Paint and I can pretty much confirm that component is a 10 µH inductor made by Fastron. (Inductor Axial lead 10 µH 0.105 Ω 3 A Fastron)
-T
great, thanks for the hint! i've never seen this part before. I'll update the gut shot later to include this info.

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Post by ppluis0 »

vintagecharlie wrote:Thanks for all the input guys!

A good soul sent me this piece of information:

"Look at the vibrochamp and remove the first input stage from the audio path and the buffer from the output of the oscillator. The rest should be really similar. Well, and you need a 250V PSU."

In fact, in his demo Simon actually mentions the Princeton and Vibrochamp as particularily nice sounding examples of tube bias tremolo. So looks like it is a pedal version of the Vibrochamp tremolo.
Hi Charlie,

The schematic of a Vibrochamp amp its at this link: http://www.thevintagesound.com/ffg/sche ... _schem.gif

At first glance the speed potentiometer match with the one seen in your picture, wich has a value of 3 Megohms, so the information you have received is accurate.

My best guess is that one triode section of the tube is used as phase shift oscillator -comprising several poly caps and resistors- and the other triode section modulates the signal.

Also the Princeton amp employs the same oscillator: http://www.thevintagesound.com/ffg/sche ... _schem.gif but the resulting waveform modulates the output tubes.

The question arising is what that transistor is used for... :hmmm:

Cheers,
Jose

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