Building a Wal....ish

[NickA]

On 02/01/2023 at 21:51, funkle said:

more flexibility to an instrument that already has too much of it.)

Very true ... But I'd like a single coil mode on my Wal.  Nice clean harmonics.  Not that I get to play such things in public.  Slap and harmonics being largely a private affair 😉

[funkle]

@Kinkh can you perhaps answer from the schematic you drew up?

 

I'm testing out the Wal and my Wal-ish side by side into a frequency analyser. I think the Wal filters seem to work down to different frequency levels for the neck and bridge pickups. 

 

Listening to it and looking at the frequency analyser, and using the filter boosts to help make peaks more obvious, I think the neck pickup filter goes down to about 100Hz, and the bridge one goes down to about 150 Hz. 

 

This is the first I have heard of this; I may not have been paying close enough attention. Are you able to help answer?

[LukeFRC]

12 minutes ago, funkle said:

@Kinkh can you perhaps answer from the schematic you drew up?

 

I'm testing out the Wal and my Wal-ish side by side into a frequency analyser. I think the Wal filters seem to work down to different frequency levels for the neck and bridge pickups. 

 

Listening to it and looking at the frequency analyser, and using the filter boosts to help make peaks more obvious, I think the neck pickup filter goes down to about 100Hz, and the bridge one goes down to about 150 Hz. 

 

This is the first I have heard of this; I may not have been paying close enough attention. Are you able to help answer?

I can remember that from my trace... they filters are set differently from each other.... how I don't know cos I didn't finish the trace. ... 

[funkle]

On 30/07/2022 at 12:16, Kinkh said:

What is interesting here is that the filters are tuned to different frequencies. The most interesting thing is how the Attack function is implemented. The signal from the Neck pickup is taken directly after the summing amp (which sums all the individual coil pairs), and put through a high-pass filter to leave only the high frequency content of that pickup. Then, that filtered signal is ADDED to the maim mix of the bridge and neck pickups after they have been filtered by their individual filter controls.

I have also made a SPICE simulation of the circuit to better show what is happening here. Due to the transistors and opamp being obsolete, I replased them with generic ones, and put a normal summing stage at the input.
When trying to build this circuit, the transistors can be omitted if a modern low noise opamp is used. This kind of stage was used in back in the day when low noise opamps were not readily available, and a simple transistor differential amp could make up for that by being added in front of the opamp.
A logical question remains: do the outdated components contribute to the sound characteristic of this preamp? Maybe, maybe not. The opamp has limited bandwidth, and the overall stages might produce some distortion. As there is no definitive datasheet info on these parameters, it's up for debate and experimentation to answer that question.

Anyways, here are the graphs from the simulations.
Pickup_01 is neck, and Pickup_02 is bridge.

 

 

 

 

@Kinkh did already answer this, and indeed the filters are set differently for the different pickups. They look to go down to where I thought they did - thank goodness my ears and my frequency analyser look to be working ok. lol 

 

[Kinkh]

@funkle Hey!
I haven't been reading this thread for quite some time, so I'm not sure what I'm missing here. I just got a notification 😅
Your question was whether the filters have different cut off frequencies, right?

Yes they do. The maximum frequency is very close on both filters, but the minimum frequency is around 100Hz for one, and around 150Hz for the other. And yes your ears were right  

[funkle]

@Kinkhthank you! I sent you a message on another issue also over on Talkbass by PM, have a quick gander there 

[funkle]

Question on bridges. 
 

I am absolutely unconvinced of the sonic differences between bridges after swapping them around on different basses myself. I’ve used Fender bent plate, Fender high mass, Hipshot A and B bridges in aluminium and brass, cheap stock ones on Ibanezes, Hipshot Vintage ones, the stock high mass one on my Squier CV Jazz, the Babicz bridge, a huge 2-Tek on my old Hamer bass, all sorts really….

I have found many whose form and function I prefer, but I just haven’t been convinced they make a huge sonic difference. 
 

I am open to persuasion, but not through long chats on here….I’ve read too many conflicting opinions.

However. If anyone has convincing links to YouTube videos or sound clips demonstrating a significant sonic difference, I’d appreciate seeing them. I would consider this the best evidence. 

Otherwise, I’ll probably just stick a brass bridge on here, as at least it has some zinc in it, which is what the Wal bridge seems mostly to be made of.  

[bloke_zero]

I thought this thread had some value. Nice little frequency analyser video later too:

 

 

[funkle]

21 minutes ago, bloke_zero said:

I thought this thread had some value. Nice little frequency analyser video later too:

 

 

Thanks for that. First time I’ve heard a convincing difference between bridges. Touch less high end on the high mass bridge.
 

Those bridges I think are both zinc? So main difference is mass, I suppose. Lol, I preferred the BBOT..

[bloke_zero]

Yes. I was surprised. I normally listen on headphones with interface but you could hear the difference on my laptop! I think the bbot sounded better.

very well presented video, which I thinks helps differentiate.

[LukeFRC]

12 hours ago, funkle said:

So main difference is mass

and design. - if the mass is used to make different bits stiffer.  
I think if you go for a similar ballpark style as Wal use you will be close enough. 

[funkle]

Presently I am planning a brass Hipshot A bridge. Now I wonder about swapping to a Hipshot Vintage one…

[funkle]

For interest. @Chopthebasshas kindly agreed to take on building a custom body for me, after we chatted when I clocked his Wal Mk3 clone build in the ‘Build Diaries’ section. 
 

He’s rather good with the CAD software, and we have a final design. Mahogany core, flame maple facings front and back. I think it looks rather good!

 

You may observe I have moved away from the Precision body design to a refined Jazz shape that is ‘reminiscent’ of a Celinder. After a decade with various Celinders I decided it’s probably my most comfortable body shape.  
 

 

Edited January 13, 2023 by funkle

[LukeFRC]

13 minutes ago, funkle said:

Presently I am planning a brass Hipshot A bridge. Now I wonder about swapping to a Hipshot Vintage one…

Purely my opinion, but the Hipshop A sounds like a good choice. 
 

I think we would agree on the importance of the neck to the sound, but in my limited experience bolting things together the bridge, and how the neck is attached to the body do make a difference. 
You've spoken about the "Wal recipe", for me the "fender recipe" includes screwed on neck (not bolts) and a vintage style bridge - change these and you start to move away from it. IMO, YMMV etc

[funkle]

We’ll be sticking to using inserts/machine bolts for the neck. The bridge, well, Hipshot A in brass presently. Easy to swap if needed..

[Andyjr1515]

2 hours ago, funkle said:

For interest. @Chopthebasshas kindly agreed to take on building a custom body for me, after we chatted when I clocked his Wal Mk3 clone build in the ‘Build Diaries’ section. 
 

He’s rather good with the CAD software, and we have a final design. Mahogany core, flame maple facings front and back. I think it looks rather good!

 

You may observe I have moved away from the Precision body design to a refined Jazz shape that is ‘reminiscent’ of a Celinder. After a decade with various Celinders I decided it’s probably my most comfortable body shape.  
 

 

Great, great choice, @funkle - @Chopthebass's builds are consistently superb...and he has a special Wal interest too

 

[bornleft]

I am curious to know if now that you have an accurate diagram of the Wal electronics, why someone couldn't just reverse engineer the

amp and pickups?  Instead of using someone else's approximation you could have exactly what you want.  The Chinese reverse engineer fighter planes,

why not some electronics...

[funkle]

15 hours ago, bornleft said:

I am curious to know if now that you have an accurate diagram of the Wal electronics, why someone couldn't just reverse engineer the

amp and pickups?  Instead of using someone else's approximation you could have exactly what you want.  The Chinese reverse engineer fighter planes,

why not some electronics...

If you are offering, I am game. 
 

No one is willing so far to make an exact copy of the preamp, at least that I can find. I may have one person who is looking at this presently, but I haven’t heard from them in a bit. Plus a few of the parts are very hard to find for making an exact clone. Nuno is definitely the closest I have found so far. 
 

The Wal pickup, well, I haven’t found anyone yet making an exact clone. Herrick use neodymium pickups, Rautia just closed up shop, Aaron Armstrong can do them but it’s £720 a set, and Chris Turner is using his own ‘near Wal’ formula which sounds great but is not an exact clone either. (Although that may change. Watch this space). 
 

I have no idea how close the Bass Culture Walbuckers are to the real deal either. 
 

Furthermore, I have recently found out that the ‘well known’ specs for the wire used in Wal pickups may be wrong. So it may be that those who have been making clones have been very slightly off. 
 

I had always found in searches that is was 42 AWG, but in fact it seems it is 0.06 metric, or 42.5 AWG equivalent. This makes a big difference when winding 10,000 winds per coil. And it’s probably another reason why people using the ‘well-known’ formula have been slightly off. 

Edited January 30, 2023 by funkle

[bornleft]

I wish I could offer... not in my wheelhouse...

But if you have a schematic with parts listed, what you need is someone in the electronics field, not in the "pre-amp" world.

Someone outside of this industry....  follow the directions, etc.

In terms of "discontinued parts", you need to look at one of recent pre-amps, where the parts are not old.  I would be

willing to bet since they only build something like 100 basses per year (just a wild donkey guess) that they can not commission

proprietary components.  They are not Fender...  Someone is supplying their parts off of the shelf.

 

So many falsities on the internet that reverse engineering would eliminate...

 

[bornleft]

 

https://rjs-electronics.com/?gclid=Cj0KCQiA8t2eBhDeARIsAAVEga3SF9_hW10T3yymRZRKcLBoDSzcumARrilsCNi6LtnHUnULLKE7xyQaAsHWEALw_wcB

 

https://prototypes.prioritydesigns.com/complete-prototypes/electronic-prototype/

 

https://www.google.com/search?q=electronic+custom+circuits+prototype+music+industry&source=lmns&bih=1085&biw=2527&client=safari&hl=en&sa=X&ved=2ahUKEwiQ1Juat-_8AhWJNd4AHbt6B7cQ_AUoAHoECAEQAA

[funkle]

58 minutes ago, bornleft said:

I wish I could offer... not in my wheelhouse...

But if you have a schematic with parts listed, what you need is someone in the electronics field, not in the "pre-amp" world.

Someone outside of this industry....  follow the directions, etc.

In terms of "discontinued parts", you need to look at one of recent pre-amps, where the parts are not old.  I would be

willing to bet since they only build something like 100 basses per year (just a wild donkey guess) that they can not commission

proprietary components.  They are not Fender...  Someone is supplying their parts off of the shelf.

 

So many falsities on the internet that reverse engineering would eliminate...

 

 

I have done my utmost to ask people to produce schematics. We have one here in the thread, a few pages back. There is another possibly coming from another interested party, I await that. 

 

They definitely have hard to find components - not proprietary, but limited supplies/out of stock and by modern standards, outdated components. I suspect Wal bought a huge supply of these older ICs and are just working through them slowly. Their production rate is so low that they probably have a lifetime supply. 

 

I have looked a couple of times at getting someone off the internet to make a custom preamp from the schematic, but I'm not sure they can get all the parts... I may yet try to go down that path, but Lusithand (Nuno) makes it so easy to just buy his that I haven't bothered.  

Edited January 30, 2023 by funkle

[LukeFRC]

55 minutes ago, bornleft said:

I wish I could offer... not in my wheelhouse...

But if you have a schematic with parts listed, what you need is someone in the electronics field, not in the "pre-amp" world.

Someone outside of this industry....  follow the directions, etc.

In terms of "discontinued parts", you need to look at one of recent pre-amps, where the parts are not old.  I would be

willing to bet since they only build something like 100 basses per year (just a wild donkey guess) that they can not commission

proprietary components.  They are not Fender...  Someone is supplying their parts off of the shelf.

 

So many falsities on the internet that reverse engineering would eliminate...

 

with a schematic it would be easy ...

 

they use a TAB1043 chipset.... including the new ones. Supposedly really low performance chip, esp at lower power... but my suspicion is that the audio crapiness of the chip is part of the sound 

[bornleft]

Look back a few pages, there is a schematic!

[funkle]

Next video is up! I actually had to learn a lot more about video editing for this one....

 

 

[funkle]

A quick update re: filter ranges from another friend working on the schematic:

 

‘Neck filter for a Wal is 85hz to 2700hz
Bridge 225hz to 2700hz. 

According to the resistors and capacitors that are in it. 

It will vary depending on how close the actual values are to what they’re supposed to be. 

Your take on the scope was pretty close’