3below Posted October 20, 2016 Share Posted October 20, 2016 [quote name='Andyjr1515' timestamp='1476997359' post='3159198'] That's very kind of you, 3below I think I'm OK - I've ordered a 20k trim pot and a .001 cap that were only a couple of £'s. A three year course in electrical systems and electronics would be useful, though, if you've got a spare one of those lying around [/quote] Can provide you with a set of course notes for A level electronics (or just the analogue sections) if you are suffering insomnia Could do with the three year course myself, I have forgotten so much, so much I have not studied. Quote Link to comment Share on other sites More sharing options...
samhay Posted October 20, 2016 Share Posted October 20, 2016 Thanks for recording the sound clip - the notch settings definitely sound quite useful. Might have to cobble something together myself. Happy to impart a little knowledge too - I am fairly sure we aren't even yet as I have learnt quite a lot reading through your build threads. Quote Link to comment Share on other sites More sharing options...
3below Posted October 20, 2016 Share Posted October 20, 2016 (edited) The power of BC, if the rest of life was this positive and helpful..... samhay any chance of a bit more modelling - see my earlier post. Thanks. Edited October 20, 2016 by 3below Quote Link to comment Share on other sites More sharing options...
samhay Posted October 21, 2016 Share Posted October 21, 2016 ^sorry, missed that post. Happy to model the mark 1 circuit. Do you know what the inductance of the choke/inductor they used is? Quote Link to comment Share on other sites More sharing options...
3below Posted October 21, 2016 Share Posted October 21, 2016 The inductor has some 'mystery' with the published figures. Allegedly a wrong value was published to lead competition astray.. I would go with the 1.5H that Andy has. What software are you modelling with? Thanks Quote Link to comment Share on other sites More sharing options...
BigRedX Posted October 21, 2016 Share Posted October 21, 2016 The 355 circuit diagram I have, gives the inductor value as 15H, but when I went to buy one from my local electronic components shop it turned out to be quite a lot larger than I was expecting! IIRC I settled for a 1.5H component (or whatever was the closest they had in stock) and ended up with something that fitted comfortably in the control cavity of the guitar I was building. Quote Link to comment Share on other sites More sharing options...
LZD56 Posted October 21, 2016 Share Posted October 21, 2016 https://www.youtube.com/watch?v=532j-186xEQ Quote Link to comment Share on other sites More sharing options...
samhay Posted October 21, 2016 Share Posted October 21, 2016 (edited) ^I can just about picture Darth Vader playing an EB-3. Probably not a fan of funk. The specs of a classic mudbucker seem to be ill-defined, but it seems that 30k and 65 H seem to be a reasonable guess. If we assume the varitone choke they used is similar to Andy's transformer - 1.5H and 150 ohm DC resistance, we get this (red trace) with the tone control all the way up (no treble cut): Edit - the notch is at ~900 Hz. Because 65H is about 20-40 x higher than a normal pickup, I also simmed this with more sane pickups with 5H and 15H inductance (green and blue traces). If you remove the inductor from circuit, you can see how much treble is naturally rolled off as you increase the inductance of the pickup (grey is 65H). 3below - I use LTSpice and have included a screen shot for your perusal. Edited October 21, 2016 by samhay Quote Link to comment Share on other sites More sharing options...
3below Posted October 21, 2016 Share Posted October 21, 2016 (edited) Samhay, thank you. Looking at your model you have LCR in series (which makes sense as a 'notch' filter). From my several trace throughs and redraws of the EB3 mk1 filter circuit I end up with pickup output into the parallel RC network in series with L to ground. The output to jack tip is taken from the node between RC and L. I am still on the learning curve of understanding what it does. The mk 1 circuit is where Andyjr started from which is why I am following it through (and pure curiosity and reminding myself of what I used to be able to do a long time ago). Edited October 21, 2016 by 3below Quote Link to comment Share on other sites More sharing options...
samhay Posted October 22, 2016 Share Posted October 22, 2016 Working from this schematic: http://www.flyguitars.com/gibson/bass/EB3_schematic.php I see the filter as the GA-90C inductor/choke and the 20n (0.02u) cap. In series, this gives a notch filter, which is what I understand the varitone to be. In my simulation: L1 and R4 are the FB pickup. I didn't model the other pickup, but this won't change the position of the notch. Pickups have both series inductance and resistance and a typical guitar pickup might have about 5-10k DC resistance and 2-3 H inductance. The mudbucker, being the beast that it is, seems to be closer to 30k and 65 H. R3 and C3 are the tone control rolled all the way up. This doesn't do much to the frequency response, as one might expect. The notch filter is L2 C2 R2. R2 is the inherent DC resistance of the inductor/choke used and I guessed at the value of 150 ohm. If this is higher/lower it will not move the notch position, but make it less/more deep. C2 is the 20n cap. You can ignore R1 - this is a way of essentially switching this part of the circuit off (sw = 1Meg) to see what the output from the pickups looks like. Quote Link to comment Share on other sites More sharing options...
White Cloud Posted October 22, 2016 Share Posted October 22, 2016 Electronics, mweh....a necessary distraction from wood loveliness Quote Link to comment Share on other sites More sharing options...
3below Posted October 22, 2016 Share Posted October 22, 2016 [quote name='White Cloud' timestamp='1477124370' post='3159954'] Electronics, mweh....a necessary distraction from wood loveliness [/quote] Occupies the time while glue is setting, varnish is drying or I am too tired and will make irreparable mistakes in wood. samhay and Andjr, thank you for providing insight, advice and encouragement for problems that I can not let go of. Spurred on by samhay I have spent some time playing with QUCS circuit simulation (which uses ngSPICE) and the original diagram Andyjr started with. Diagrams and data to follow, but the broad picture is that the early circuit is a high pass filter. Having owned a 58 EB2 many years ago this is exactly what the 'baritone' switch did - removed some 'muddiness'. What is interesting is the effect of the inductance of the 'mudbucker'. Although I measured the voltage output iof my EB2 at 1.5V ish E string (Sixth form Physics) The modelled values give an output voltage way below this. I did not measure the inductance of my EB2 nor have I found the inductance on the internet either. More thinking, modelling and some diagrams to follow. I need to find the inductance of the DiMarzio as well. Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted October 23, 2016 Author Share Posted October 23, 2016 (edited) I may well run out of time, 3below, but I think I should be able to rig up a working high pass filter as one of the other switch options Although my original attempt failed, that was probably more due to a wiring error I corrected when I followed samhay's diagram and the suggestion of a much lower resistor. Had I done the same two changes on the parallel version, I may well have come out with a fully functioning high pass! In that all I'm trying to do is give a variety of usable sounds with positions 4,5, 6, options of high capacitor notch, low capacitor notch and high pass could be a good plan (if I can get it to work!) Edited October 23, 2016 by Andyjr1515 Quote Link to comment Share on other sites More sharing options...
samhay Posted October 23, 2016 Share Posted October 23, 2016 High pass and low pass are easy - you only need a resistor and capacitor. For high pass, put a capacitor between the pickup and volume pot (i.e. in series with the pickup). If you are using a 500k volume pot, then try cap values of about 2.2n (0.002). Bigger values give more bass/lower corner frequency and vice versa. Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted October 23, 2016 Author Share Posted October 23, 2016 [quote name='samhay' timestamp='1477212786' post='3160519'] High pass and low pass are easy - you only need a resistor and capacitor. For high pass, put a capacitor between the pickup and volume pot (i.e. in series with the pickup). If you are using a 500k volume pot, then try cap values of about 2.2n (0.002). Bigger values give more bass/lower corner frequency and vice versa. [/quote] Brilliant - thanks, samhay Will be back in the workshop on Wed. I'll let you know how I get on Quote Link to comment Share on other sites More sharing options...
3below Posted October 23, 2016 Share Posted October 23, 2016 [quote name='samhay' timestamp='1477212786' post='3160519'] High pass and low pass are easy - you only need a resistor and capacitor. For high pass, put a capacitor between the pickup and volume pot (i.e. in series with the pickup). If you are using a 500k volume pot, then try cap values of about 2.2n (0.002). Bigger values give more bass/lower corner frequency and vice versa. [/quote] Following on from this, combining the two filter types will give a notch just using RC if you want. [url="http://www.learningaboutelectronics.com/Articles/Notch-filter-calculator.php"]http://www.learningaboutelectronics.com/Articles/Notch-filter-calculator.php[/url] (this is just the first site I stumbled across). Too much choice, too little time left Quote Link to comment Share on other sites More sharing options...
TheGreek Posted October 23, 2016 Share Posted October 23, 2016 He'll need one of these eventually: http://www.ebay.co.uk/itm/Gibson-SG-bass-hardcase-/361773242199?hash=item543b5d9757:g:Z-8AAOSwYIxYA8Sy Not mine... Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted October 23, 2016 Author Share Posted October 23, 2016 [quote name='TheGreek' timestamp='1477226789' post='3160671'] He'll need one of these eventually: http://www.ebay.co.uk/itm/Gibson-SG-bass-hardcase-/361773242199?hash=item543b5d9757:g:Z-8AAOSwYIxYA8Sy Not mine... [/quote] In fact, Pete's asked me to get him a hard case. Trouble is, I'm not at home and can't be sure what length this build is... Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted October 25, 2016 Author Share Posted October 25, 2016 (edited) OK Back from Scotland this afternoon and straight down into the cellar to sort the soldering I was cogitating about while I was away ...and, as far as the electronics go, it's finished This is what it finally looks like: I have it now set up as:[list] [*]Pos 1 - bridge only [*]Pos 2 - bridge and neck [*]Pos 3 - neck only [*]Pos 4 - neck with notch filter incl 0.001uF capacitor [*]Pos 5 - neck with notch filter incl 0.010uF capacitor [*]Pos 6 - neck with notch filter incl 0.047uF capacitor [/list] This gives me six fully usable and distinctly different sounds, with positions 4, 5 and 6 being variations of position 3 progressing towards the bass end. I've done some sound clips through my little Vox electric guitar amp which I will post but tomorrow I'll also see if I can get some better clips through the PA speakers. Tomorrow should see this pretty much finished excepting popping some roundwounds on (any suggestions anyone?) and getting a hard case for it. Edited September 29, 2017 by Andyjr1515 Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted October 25, 2016 Author Share Posted October 25, 2016 (edited) [url="https://soundcloud.com/andy-rogers-6/custom-eb-3-style-sound-clips"]Comparative sounds, now through a small PA, here[/url] Edited October 26, 2016 by Andyjr1515 Quote Link to comment Share on other sites More sharing options...
Oopsdabassist Posted October 25, 2016 Share Posted October 25, 2016 Those notch filter sounds are very nice, the bridge on its own is too zingy for my taste, but a great range there I reckon! Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted October 26, 2016 Author Share Posted October 26, 2016 (edited) [quote name='Oopsdabassist' timestamp='1477432069' post='3162266'] Those notch filter sounds are very nice, the bridge on its own is too zingy for my taste, but a great range there I reckon! [/quote] Thanks I'm going to try it through the PA speakers later this morning. Ref the zingyness, the tone knobs are on 10 and do tone it down nicely. However, the surprisingly zingy one is the 'both on'. For certain things it is very useable, but it surprised me that adding in the mudbucker to the bridge makes it even more metallic! I checked to make sure I hadn't inadvertently set it out of phase but pretty sure it's not. In this setting there is also a sweet spot as you tweak the bridge vol down where there is a fuller sound but still different to the others. Pity Pete will probably just use one tone...and that one will be the one that the selector just happens to be on when he plugs in Edited October 26, 2016 by Andyjr1515 Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted October 26, 2016 Author Share Posted October 26, 2016 Hi [url="https://soundcloud.com/andy-rogers-6/custom-eb-3-style-sound-clips"]Re-done the sound clips of the 6 positions through our small Yamaha PA here[/url] The sound difference between a couple of the notch positions on the recording is subtle but live is definitely discernible and is more apparent with different styles of play Sorted the brass nut, replacing the zero-fret: Just got to tidy up the back of the neck, get some round-wounds and a case and it's done Quote Link to comment Share on other sites More sharing options...
White Cloud Posted October 26, 2016 Share Posted October 26, 2016 Wonderful sounding bass, you have built an absolute cracker. Congratulations you should be proud of yourself! Quote Link to comment Share on other sites More sharing options...
3below Posted October 26, 2016 Share Posted October 26, 2016 The bar has been set high Quote Link to comment Share on other sites More sharing options...
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