Double Bass Yamahiko Double Bass Pickup

[Karl Kaminski]

Karl: I had Mr Y build a Yamahiko with reversed phase (I have it on my other bass and bridged) it is great and gets to the same place as flipping the phase one one ch of the felix

Way back in the 90s Mr Y gave me various attenuated jacks (that was the only 'mod' at that time.) Over the years, Ive repaired the SSMA leads myself, but never thought of going that extra mile to make a reversed-polarity lead to bridge the two pickups. Please correct me if Im wrong but changing the phrase is merely swapping the polarity of a lead, right? (If so thats an easy experiment )

 

[flatback]

No I don't think so. It is all earlier in this thread ....It was a couple years ago so I forget. But I think it is not just switched leads....It definitely took him a while to build it....

 

[crd]

Way back in the 90s Mr Y gave me various attenuated jacks (that was the only 'mod' at that time.) Over the years, Ive repaired the SSMA leads myself, but never thought of going that extra mile to make a reversed-polarity lead to bridge the two pickups. Please correct me if Im wrong but changing the phrase is merely swapping the polarity of a lead, right? (If so thats an easy experiment )

I think you can do this easily with the cable. I am just guessing though because I have no real electrical engineering knowledge, just lots of time futzing with my bass and reading manuals. I think part of the advantage of the TRS set-up is there is something to be gained by buffering each pickup independently before mixing them. I have one side buffered at 20 m and the other at 10 m. Unlike most pickups that sound bad at 10m the Y actually benefits from higher impedances.

 

[flatback]

One of my all time favorite electro/acoustic albums is Three quartets by Chick Corea. Eddie Gomez is just utterly stunning playing that music, a full equal partner and some of his solos use vocabulary that no one uses or has used since. He is such a motherF. I was listening to that this morning and kinda of instotranscribing as I played a long and I DO remember first wanting the Y to try and get some of that mojo way back,.... he is playing a lot of sequential 4thy stuff and kinda of Brecker on bass stuff that just kills. You cant hear ANY Eddie singing in the back round so Im thinking he is 100% direct in the studio maybe going into an Avalon U5 or something. But BALLS man.
part of the electro part I always thought was Eddies tone and the other part was Steve Gadds drum heads....

 

[lowfreqgeek]

So I have the older Rev 1 Felix (silver), which I find to be extremely versatile. I could look up the manual and all that, but does the older Felix allow TRS input on CH2 that can be split into both channels? Am I understanding that right?

I don't have a Yamahiko, and I don't even have adjusters on my bass. I've never been real happy with the Realist on my bass, but never felt the Full Circle (which I had on a previous bass) was worth installing adjusters for. However, I could be tempted by the Yamahiko, and even more so hearing these descriptions and already having the Felix in my tool bag. I've most often used an AMT S25B with the Felix live, but even that has it's own issues, so I've been mostly using the Realist only unless the stage was big enough to handle the mic without too much bleed. Maybe it's time to do something different.

 

[Karl Kaminski]

I think you can do this easily with the cable. I am just guessing though because I have no real electrical engineering knowledge, just lots of time futzing with my bass and reading manuals. I think part of the advantage of the TRS set-up is there is something to be gained by buffering each pickup independently before mixing them. I have one side buffered at 20 m and the other at 10 m. Unlike most pickups that sound bad at 10m the Y actually benefits from higher impedances.

Ive actually been a long time user of the 10MΩ impedance (Yamaya-san recommended the 10MΩ Countryman as the DI wayback in the 90s)—though IDK what the suggested impedance is for his new products. My setup is mono TS and while the TRS is a great option I don't have that at my disposal. (I guess making one isn't out of the question)

 

[Karl Kaminski]

No I don't think so. It is all earlier in this thread ....It was a couple years ago so I forget. But I think it is not just switched leads....It definitely took him a while to build it....

Ah dig it, well its been almost 30yrs, guess it time to upgrade and order a new set from him

 

[Hasty]

Well, since I'm always in search of a new project... this conversation today inspired me to consider a buffer/phase inverter. I found a fairly simple schematic and whipped this up on KiCAD. I'll see if I have the parts to breadboard it and if it works I'll order a few PCB's. Might be a nice little pedal to have available if I need it.

 

[flatback]

Yamaya-San I like that....
Hey Yamaya-San will sell you one wired that way for about 40 bucks. I have two of them (one made locally by @Maple) who also uses this TRS setup.

 

[lowfreqgeek]

Well, since I'm always in search of a new project... this conversation today inspired me to consider a buffer/phase inverter. I found a fairly simple schematic and whipped this up on KiCAD. I'll see if I have the parts to breadboard it and if it works I'll order a few PCB's. Might be a nice little pedal to have available if I need it.

View attachment 5008943

Can you share the full schematic? You'll probably want some bypass caps on the pin 8 (V+), and it looks like the outputs are DC-coupled. Since it's single supply, the outputs will be biased at 1/2 V+, based on what I'm seeing. Also, if you use a 1Meg at R1, you'll limit the input impedance to 1Meg ohm. You could swap in a 10Meg, of course, or whatever you want, or use a switch to select between a few resistors.

I'm also a little unsure of C2 on pin 5 (+in channel 2).

 

[Hasty]

Can you share the full schematic? You'll probably want some bypass caps on the pin 8 (V+), and it looks like the outputs are DC-coupled. Since it's single supply, the outputs will be biased at 1/2 V+, based on what I'm seeing. Also, if you use a 1Meg at R1, you'll limit the input impedance to 1Meg ohm. You could swap in a 10Meg, of course, or whatever you want, or use a switch to select between a few resistors.

I'm also a little unsure of C2 on pin 5 (+in channel 2).

Good catch. I forgot to add an output capacitor. I'm sure I would have figured that out eventually after a little frustration.

I agree that I'll likely swap the input from 1M to 10M. I sketched it out directly from the schematic so I haven't done anything else with it yet. I usually stay true to the schematic until I test it out to see what I think of it. I threw it on a PCB because it was on the phone for a bit and it was a super simple circuit to throw on there.

I'm a sucker for interesting schematics that have less than 20 parts. I build out a bunch of them, then never do anything with them... but a phase switch sounds useful. If I don't like this one I'll find another circuit I like better, that's the beauty of breadboarding.

Here's a link to the circuit:

Link Removed

Link Removed

 

[crd]

Ive actually been a long time user of the 10MΩ impedance (Yamaya-san recommended the 10MΩ Countryman as the DI wayback in the 90s)—though IDK what the suggested impedance is for his new products. My setup is mono TS and while the TRS is a great option I don't have that at my disposal. (I guess making one isn't out of the question)

I don't think anything has changed in his design! Just to clarify -- I think it is possible for you to invert the phase with the bridge cable. I don't know how that sounds. I was just referring to a possible benefit of the stereo set up is being able to buffer each side independently. I'm not going to pretend to know to real world implications of all the variations in set-up because I don't, but at least in theory it's best to buffer the signals before you mix them.

 

[Maple]

I don't think anything has changed in his design! Just to clarify -- I think it is possible for you to invert the phase with the bridge cable. I don't know how that sounds. I was just referring to a possible benefit of the stereo set up is being able to buffer each side independently. I'm not going to pretend to know to real world implications of all the variations in set-up because I don't, but at least in theory it's best to buffer the signals before you mix them.

A cable alone won’t work to invert because one of the two leads serves as the shielding for the whole system and this is a feature of the hardware

 

[lowfreqgeek]

Good catch. I forgot to add an output capacitor. I'm sure I would have figured that out eventually after a little frustration.

I agree that I'll likely swap the input from 1M to 10M. I sketched it out directly from the schematic so I haven't done anything else with it yet. I usually stay true to the schematic until I test it out to see what I think of it. I threw it on a PCB because it was on the phone for a bit and it was a super simple circuit to throw on there.

I'm a sucker for interesting schematics that have less than 20 parts. I build out a bunch of them, then never do anything with them... but a phase switch sounds useful. If I don't like this one I'll find another circuit I like better, that's the beauty of breadboarding.

Here's a link to the circuit:

Link Removed

Link Removed

Ah, yes, this makes sense. I just wasn't 100% sure of the connections on the back side, but you definitely want to add some bypass caps (1uF, 0.1uF ceramic) on pin 8 and an AC coupling cap on each output. You'll need to make sure those are appropriate for the load, so if you're driving into a high-impedance input (say another 1M or 10M), you can use the same 100nF used on the input. If you're driving into a low-impedance (10k line input, for example), you'll want to bump that up to like 100uF (electrolytic) or better so as to not roll off the lows. Of course, you can always use that to make a HPF, if you know what impedance you're driving.

 

[DoubleMIDI]

Maple is right. You can exchange the poles of the cable, but since the casing is connected to the cable shield the hot amp input goes then to the cable shield and adjuster case which gives you noise from electrical fields.
Not recommended. An electronic phase inverter should be used instead.

 

[Karl Kaminski]

Thanks guys. @DoubleMIDI, I was hoping that you'd chime in . Guess I'll just keep playing my OG Yamahiko's mono or solo for now. Maybe I'll get myself a new pair in TRS 1/4"x20 for ma birphday.

 

[crd]

@lowfreqgeek
Electrical engineer? and bassist?!? So glad you're here. We need you.

 

[Hasty]

Ah, yes, this makes sense. I just wasn't 100% sure of the connections on the back side, but you definitely want to add some bypass caps (1uF, 0.1uF ceramic) on pin 8 and an AC coupling cap on each output. You'll need to make sure those are appropriate for the load, so if you're driving into a high-impedance input (say another 1M or 10M), you can use the same 100nF used on the input. If you're driving into a low-impedance (10k line input, for example), you'll want to bump that up to like 100uF (electrolytic) or better so as to not roll off the lows. Of course, you can always use that to make a HPF, if you know what impedance you're driving.

Made a few updates to the schematic and ran it through falstad.com just to see if it would do anything. While I feel like falstad is more of a fun time project instead of a diagnostic tool, it's an easy way to see if I'm in the ballpark. It was pretty cool to see it flipping back and forth on the little scope. This afternoon I'll see if I have enough parts to breadboard it and try it out. If so it might be a reasonable option for the dual Yamahiko setup. I'll end the thread hijack here unless something amazing happens.

Thanks for all the good feedback. Gave me some great ideas.

 

[Hasty]

So I have the older Rev 1 Felix (silver), which I find to be extremely versatile. I could look up the manual and all that, but does the older Felix allow TRS input on CH2 that can be split into both channels? Am I understanding that right?

I just read that in the manual (8.1) and confirmed with a little testing. It was nice to only run a single TRS cable back and not worry about splitting anything manually.

I never thought I'd say this... but the ability to split those pickups, adjust the phase, and EQ each pickup individually through the Felix is putting my ToneDexter at serious risk of going in the closet. I just spent an hour playing around with it and adjusting some settings. I won't be so bold as to say that it sounds like a microphone, but it's scary just how close it is tone wise to my ToneDexter right now.

I've got a few gigs coming up so I'll test it at louder volumes and in different rooms but if it sounds as good as it does right now I might be selling that ToneDexter soon. Every single complaint I had about the Yamahiko (and TBH there were only a couple) when I was running mono have completely evaporated. Everything that I needed to ToneDexter to correct isn't present anymore.

 

[flatback]

Yeah I'm liking it too. I encourage you to experiment with the HPF's, as part of the sound.