The Guitar Gallery Forums - The Guitar Legacy of Matsumoku

Hi everyone.

I am new here but have been collecting Aria Basses over the past year or so.
I have just completed adding a varitone to my post Matsumoku Elite 2.
I have documented the procedure with some sound bytes for anyone interested.
I am sure this is a non-destructive mod for most passive models not just the Elite.
https://sites.google.com/site/ariapro2elite2hacks/home

Best regards

Tee.

Nice Job! Thanks for sharing. I've toyed with the idea of doing some electronics mods to my TSB-400, but haven't quite figured out exactly what I'd like to do yet. For now about all I've done is replaced the 3 way switch with a volume control for the second pickup to give me a J-bass like control set-up.
I'm also lucky enough to own an SB1000, and can say with certainty that it is the first active bass I've ever owned that I've liked the sound of. Everything else I have is passive.

Thanks again for the detailed post- well done!

Cheers,
G

Thanks for the kind words.

I am thinking to add sound bytes from my SB-1000 later so folks can compare my passive varitone.

Cheers!

I second that movement, Gribb. A very well thought out and excellent overhaul. How do you plan on securing the transformer within the cavity? I presume that the transformer is a small PCB-mounting type as opposed to chassis mounting, so epoxying/soldering the casing to the cavity wall/floor or similar might work best?

I can't check out the soundclips here, however I can't wait to check them out at home!

_________________
"People demand freedom of speech as a compensation for the freedom of thought which they seldom use" - Søren Kierkegaard
"It looks just like a Telefunken U47" - Frank Zappa

Hi Prostheta,

Yes, you are correct. The audio transformer is a PCB mounting type with 2 small lugs one on each side. At the moment I've left it floating its quite secure by the stiffness in the wires, however next time I open the cavity I intend to solder it in place by the lugs against the copper tape. Epoxy of course works fine, but you can't de-epoxy, but you can de-solder

I did experiment with another audio transformer which was rated at 7 Henry but the sound was far too dark and there were no discern-able harmonics present in the sound. 1.5 Henry seems to be about right for a bass perhaps even 1 Henry would be a good choice. Anything less than that is probably only going to have effect on a lead guitar.

Thanks for the post and the comment.

Best regards

Tee.

Interesting use of an inductor. Having thrown the idea around in my head today, I figured that why not simulate an inductor using a simple gyrator circuit? Of course, this means an active circuit as opposed to your purely passive configuration. I'll play around with some ideas when I prototype up my BB replacement, and if I can get ahold of such a high value of inductor, A/B them. Using a gyrator, it is possible to make the simulated inductor variable also. Oh, you've got me thinking now. Argh! I hate working out the maths with inductors!

I've just listened to the clips and the bass sounds nice and flexible! You've got something kooky going on in your bass somewhere with that vibration however. Perhaps the string length between the headstock and the tuning pegs or the trussrod? I hear this a lot on instruments recorded on YouTube. When I record, I wind some electrical tape around the free string lengths to prevent resonances which can leak through into the "actual" vibrating string length. A piece of foam rubber the same as used under pickups does the job well also. It might be something else, but hey.

_________________
"People demand freedom of speech as a compensation for the freedom of thought which they seldom use" - Søren Kierkegaard
"It looks just like a Telefunken U47" - Frank Zappa

Hi Prostheta,

Takes me back a bit. I had completely forgotten about the gyrator. I remember studying the concept briefly at college in the 1970's. Then it was a relatively new concept. I had to go and research all over again and get the grey matter working again. In principal you are correct. It should be possible to simulate an inductor using an op-amp. One of the reasons given for the use of a gyrator circuit was to reduce size because coils and physical windings take up space.
Certainly an op-amp IC and a few passives could be shrunk down to a fingernail sized board, but then there is the battery. A regular pp3 type battery is about 3 times the size of the transformer I am using. Already a catch 22 situation. However, if the design is to be active from the offset this is not a consideration. For a future project I am looking at combining one or 2 magnetic pickups with a piezo each with individual volume pots and either active 3 band EQ or another varitone. I like the idea of the infra-red "lightwave" pickups, however they are under copyright control and anything more than home experimentation is forbidden. I am also thinking about reverse engineering a moving coil microphone insert to act as an audio transducer rather like a piezo. Just like a piezo pickup, it would need a 0Db buffer stage to change the impedance, in this case it would be to raise the impedance and not lower it. That is an experiment for a very rainy day. I was also thinking that with a physical metal lever attached to the instrument and the other end connected to the transducer there could be some mechanical amplification if the signal is too weak.... Now my head is spinning and I need another beer, but its only 8am!

Regarding the sounds on the recording. I was using round wound strings and steels. I have a nickel allergy and I am forced to use steel strings. Even then most frets have nickel content so I still have an allergic reaction when I play for a while. I prefer flats anyway for the smoother sound and less finger noise. I remember that my finger was hurting a bit that day and my hand was probably not at its best. Usually that Elite sounds good without any extraneous harmonics. More likely me rather than the guitar.

For anyone interested in the basics of a gyrator here is a link I Googled this morning.
http://sound.westhost.com/dwopa.htm#inductor

By the way are you the guy that Jason has been communicating with about the the BB circuit replacement?


Best regards

Tee.

I am indeed! Sounds like you are wrestling with trying to remember your electronics education the same as I am! It's been fourteen years since I truly did any theoretical work, but it is proving very worthwhile. I posted a thread on the BB here, and also we have a very likely candidate for why they seem so prone to failure. Along with bridges, I plan to do a small run of BB circuit replacements with either the same 10-way Molex or screw terminals for retrofitting passive basses. I could also do with figuring out the 11-way versions.

With a bit of wizardry, I might even be able to make a "standard" BB with an optional parametric control based around a gyrator. I love the idea of multipurpose modular preamps!

_________________
"People demand freedom of speech as a compensation for the freedom of thought which they seldom use" - Søren Kierkegaard
"It looks just like a Telefunken U47" - Frank Zappa

Good morning Carl,

That is interesting and although we are specifically talking about Aria Pro SB models here, I've been discussing with a buddy here in Japan about making a limited run of very high quality bass guitars. A modular pre-amp would be one of the things we would consider as well as modular pickups.
So you could virtually plug in one or two pickups magnetic single coil, humbucking dual coil or piezo and a matching preamp and EQ unit that is configured for the pickups. Or simply build a pre-amp capable of taking high and low impedance pickups and balance them into the EQ section.

I haven't done any research myself but lurking in forums it seems discrete JFETS are the way to go for quiet operation and smooth harmonic characteristics. There are even some JFET schematics based on old valve amp designs with a similar sound. Op-amps seem to be (others opinions) noisy and distort in a nasty way. I will obviously have to do some testing myself, but discrete components mean easier to repair.

For design we are thinking something like a cross between an SB and an Ibanez Ergodyne shape, through neck and through body string anchors to add that extra bit of sustain and clarity. We are just at the drawing board at the moment. My buddy is a highly skilled cabinet maker by trade and also works with CNC, I'll be in charge of the electronics and design concept and there is another guy who is a luthier and will help us to set-up the completed instruments. Reckon its a year's work in our spare time.

Still that is getting off topic now so happy to discuss further in private.

Best regards

Tee.

That sounds like a fantastic project Tee. I agree that FETs have the edge on op-amps for those reasons, hence why I intend to produce a couple of "BB" designs based around the original op-amp based design, and then around a FET buffer. To be fair, I can't see that they would make a massive amount of difference and when you start producing circuits in quantity, the cost saving of using integrated parts such as op-amps becomes a matter of overall profitability as opposed to a "one-off purist's" approach of most fit for the job. Even WAL and Alembic circuits use(d) ICs rather than FETs, although I suspect not for the cost savings.

I recently purchased a large quantity of different NOS germanium diodes which I intend to use in a harmonic sweetening circuit. Not exactly a new design, however as part of a pre-amp it might be a nice option. If any of my work is of use to you guys, then I would be more than happy to alter them with your intentions in mind. In the respect of the modular approach you mention, and you thinking of "swappable pickups" or a "one size fits all" pre-amp? I think the latter is a better idea otherwise your run of X basses becomes a run of X all-individual basses, with the additional work that goes with that. I'm sure you know this already as you seem to think along the same general lines as myself (I'm a self-confessed rocket scientist!).

Your inductor idea has sparked me into thinking about creating a HiFi sounding pickup with a low inductance and with a gyrator in the pre-amp bringing in variable resonance peaks similar to how higher inductance pickups react. At this point things become a little more MEF, although not outside of my capabilities.

I think I might be able to provide input in terms of the hardware also, ie. bridges. An evolution on the SB bridge would be one that offers the hook loading as per the SB, with an option for through-stringing into a specially fitted plate at the rear of the instrument. I'm especially interested in the "rear loading" of Pete/Bloodaxes RSB-5 Deluxe also. A very rare variant on the SB bridge that actually seems a better design. No idea why that was never taken into the rest of the range.

By all means we can take this to PM, sounds good. I'll continue to develop the BB alternatives and some of my other work publicly though, as I think it is of specific benefit to the Mat community at large, especially when some replacement parts are real dog eggs to find. Wait, that's not the right term. Hen's teeth. Dog eggs are all over the place.

_________________
"People demand freedom of speech as a compensation for the freedom of thought which they seldom use" - Søren Kierkegaard
"It looks just like a Telefunken U47" - Frank Zappa