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Building a Wal....ish


funkle

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2 hours ago, funkle said:

I’m amazed someone in China hasn’t already done this.

Maybe they will now the hard work has been done for them! :)

 

Generally, the chinese factories wont bother copying anything technically complex, especially if it involves research and development.  This is from a chinese entrepreneur i know.

 

4 hours ago, Passinwind said:

 I can start a design from scratch today and have a finished build by the end of next week very economically, no problem.

How's that passive circuit we discussed coming along?

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13 hours ago, funkle said:

Side note, I heard some sound clips of the Underhill filter preamp today and it sounded great. It also had a gritty quality to the sound, which I did not expect. It may be another strong contender. However I don’t know if I can face another preamp test with the present one already waiting in the wings. 

That looks really interesting - I couldn't see any clips on their site or on youtube - do you have a URL? Thanks!

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1 hour ago, bloke_zero said:

That looks really interesting - I couldn't see any clips on their site or on youtube - do you have a URL? Thanks!


I don’t have a URL, just a link sent to me by Facebook messenger. I can’t seem to download it or share it, annoyingly - looks like I can only message it to friends on FB. 

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24 minutes ago, funkle said:

@bloke_zero Chris ( @slowburnaz) has a clip of the Underhill filter pre with a single MM pickup - 

 

https://on.soundcloud.com/sv82Q

 

Sounds great to me. 
 

Chris is getting a wider range of pickups now…I’m going to need him to explain all of the models!

 

 

Heh...  so, the "SPPP" variant that this was recorded with is the successor to the "SPSC" variant that Pete has in his Wal-ish.  The series and parallel modes are the the same for both variants.  The difference is in the other available switching options:  the SPSC variant allowed for choosing either single row of 4 coils to effectively make a "single coil".  The SPPP variant allows for either a "standard P" or "reverse P" option... think neck-side E and A coils in series with the bridge-side D and G coils (or vice versa). 

 

This clip was all in series mode.

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14 hours ago, funkle said:

@bloke_zero Chris ( @slowburnaz) has a clip of the Underhill filter pre with a single MM pickup - 

 

https://on.soundcloud.com/sv82Q

 

Sounds great to me. 
 

Chris is getting a wider range of pickups now…I’m going to need him to explain all of the models!

The first 3 seconds had me hooked! I see what you mean, not clean but super present while remaining, er, for lack of better words 'contextualised' - they sound like they are coming from somewhere rather than all around you. If you get me. Which is something I value in recording.

Nice, thanks for digging that out! And the recording @slowburnaz!

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On 05/04/2023 at 02:13, Passinwind said:

I got a headache looking at it and quickly gave up trying to make sense out of it, in all honesty. Have you managed to sort it out though?

Different thing, you were working on a passive filtering circuit for bass and had given it to a buddy to test. 

 

The circuit i drew up was for guitar and yes not only completed it but added a locally sourced switchable mid boost (+25db @500Hz).  The first draft of the new diagram is a rats nest but I know how it all works now. 

 

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6 hours ago, bornleft said:

So what happened to the guy who was reverse engineering the pre-amp-  the guy who you said had a flood...?


He sent me the Wal clone pre that I showed a photo of, and which I will test out as able. Probably after the new body. 

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Ok guys, this is the best quality scan I can get of the paper copy sent to me of the Wal Custom preamp. It's not ideal as it was printed out lightly to start off with. 

 

It may have some values for parts not present on @Kinkh's version, I'm not sure. I'm tagging @Kinkh so he can see there may be some updated parts values and he can also update his own schematic/modelling as well. 

 

938687432_WalCustomPreampedit.thumb.png.61ccc5b7ddbedf279e2fa6787c106648.png

Edited by funkle
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6 hours ago, funkle said:

Ok guys, this is the best quality scan I can get of the paper copy sent to me of the Wal Custom preamp. It's not ideal as it was printed out lightly to start off with. 

Putting it in a photo editor and inverting black and white via an edge detection algorithm made it quite a bit easier to read, FWIW.

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14 minutes ago, Passinwind said:

Putting it in a photo editor and inverting black and white via an edge detection algorithm made it quite a bit easier to read, FWIW.


Can you repost it back up please? I actually tried doing some stuff in a photo editor but then it wouldn't save, for no obvious reason...

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29 minutes ago, funkle said:


Can you repost it back up please? I actually tried doing some stuff in a photo editor but then it wouldn't save, for no obvious reason...

WalCustomPreampedit.thumb.png.08a5df0abc6a13c25ba4f170dc908057.png

 

 

I can take a stab at doing a better one later, but at least it's mostly readable now.

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1 hour ago, crazycloud said:

You can copyright it, but if it's cloned, then it costs a lot of money to defend, even in a first world country.

But that’s only copyrighting the layout or schematic drawing - you could just redraw the same circuit in a different way

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Seems mighty complicated for what it does ( buffer each pickup, filter each pickup, sum them together, add in some hp filtered signal for pick attack ).  And capacitors all over the place! And why those transistors? Weird stinky poo.   One thing is that transistors are not very linear, so probably putting those in creates some distortion ...in which case using just the right transistor might be important.

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12 minutes ago, NickA said:

Seems mighty complicated for what it does ( buffer each pickup, filter each pickup, sum them together, add in some hp filtered signal for pick attack ).  And capacitors all over the place! And why those transistors? Weird stinky poo.   One thing is that transistors are not very linear, so probably putting those in creates some distortion ...in which case using just the right transistor might be important.

No comment.

 

Nice to get a look at it though. Thanks Funkle and Passinwind!

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My own version of the Wal electronics was a purely functional copy with no attempt to emulate the exact sound ... couple of FET x4 op-amps, a few resistors and four pots.  It worked pretty well, but wassn't reliable.  That particular bass now has an East ACG-EQ-01 in it that can do "some" wal like noises but really isn't the same as (like my own design) is as linear and wide bandwidth as possible!!  Did Wal deliberately degrade the sound path to get a more "organic" sound or is it just a happy accident? !!  Who knows.  Sadly we can't ask him and Paul is just making new from the old schematics I think.

 

Anyway it's really interesting to see the schematic as I've been sort of meaning to go through my own Wal to do that ... and now will never need to 🙂

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