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Post by flateric on Jan 25, 2010 16:46:23 GMT -5
In search of my ultimate bass distortion/overdrive, I've been contemplating a new pedal build based on my favourite guitar overdrive , the Tubescreamer 808. Made a few of these for guitar now and they are great, rich harmonic overdrive, but high mid range boost means they are awful for Bass.
There's a few posts on stompbox forums, Aaron Nelson, etc. with some info on modding tubescreamers to make them more bass frequency-frienly and I wondered if anyone had any experience with these mods and the sounds they can give.
Example: the tiny 51pF cap on the standard TS-808 circuit can be replaced with a 0.47uF cap, says Mr. Nelson, to extend the circuit's distortion/overdrive as low as 72Hz. there are other '(AMZ) Phat' mods bypassing a second 0.047uF cap, as well as adding a mini switch to toggle in a third assymetric diode to give a 'more tube-like' sound, a smoother cut off to the sine wave, nowhere near as harsh as a fuzz box square wave.
I thought I'd have a go at putting all these mods + switch options onto one BassScreamer pedal and see how it works out, but be interested to hear from anyone else that's already explored the use of the modified ts circuit for bass.
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Post by JohnH on Jan 25, 2010 17:50:22 GMT -5
Sounds like fun - I havent played with ts circuits though.
But im here to plug that JFET overdrive circuit of mine! - because I think it could work well with bass too. It is highly configuable by setting the r and c values of the off board components, and I have a 5Spice model of it so it can be easily tuned to whatever response is wanted (ie, I can help with that). As drawn, the low range overdrive is a flat boost over most of the spectrum, which might already be just the ticket.
John
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Post by flateric on Jan 25, 2010 18:09:04 GMT -5
well plugged sir, componenets are ordered for the JH Bluejuice, embarassingly i just realised i was just out of perfboard as it needed to be 20 strips wide, so i need to get another sheet in.
(Had this TS-808 pcb etched months ago and it was time to use it or see all the copper go bad on me)
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Post by flateric on Jan 28, 2010 10:55:16 GMT -5
Example: the tiny 51pF cap on the standard TS-808 circuit can be replaced with a 0.47uF cap, says Mr. Nelson, to extend the circuit's distortion/overdrive as low as 72Hz. Misinformation - my bad, leave the 51pF cap alone, its the previous 0.047uF cap that feeds intot eh parallel diode clipping section that needs bypassing or changing to a 0.47uF for best bass response. |
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Post by flateric on Jan 30, 2010 9:34:55 GMT -5
 Finished the build, pretty pleased with the results. We have a standard classic TS808 circuit from DIYStompbox galley: www.aronnelson.com/gallery/main.php/v/MarkMs-Gallery/album15/album76/TS808_TubeScreamer_LAYOUT.gif.htmlThen D1 has been put on a DPDT switch with a second 4148 diode siwtchable in series to give the FULL or SOFT clip option, I've wired up an ON/OFF/ON mini toggle switch to where C4 was sitting and wired so it gives either 0.047uF cap, 0.47uF cap or both in series to radically change the tone range. the rest of the circuit is pretty much stock. With lead guitar feeding into it, the pedal gives the expected lovely rich overdrive with the mid/high boost tone, that is with clipping on full and range on high. Switching range to mid or Phat gives a great heavy bass boost to the signal, maybe too flabby for some high gain stuff but maybe superb for baritone metal riffs. Switching clipping to soft introduces the third diode and assymetric clipping, which softens down the distortion gain quite a bit while giving a more creamy smooth softer tone. Very nice. With bass, you really need tone range on PHAT or you just get a bit too much mid honk. Seems to work best with clipping on soft and gain up at half to give a softer fuzz-type overdrive. If you want to get really nasty, put the clip on FULL, the range on MID and bring the vol back a bit - very sharp aggressive tone, cuts out any bass flab, sounds more like a nasty fuzz. Seems this little mod gives a pedal that should be incredibly versatile for either bass or lead guitar. Will be trying it out live at next Friday's gig in Wooldale. Very constructive way to spend a Saturday morning  |
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Post by ashcatlt on Jan 30, 2010 11:04:20 GMT -5
Post samples!
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Post by cynical1 on Jan 30, 2010 11:12:19 GMT -5
Another reason why I wish I'd paid more attention to this stuff when I was in school...
+1 for a very useful pedal for folks who dabble in both guitar and bass, but don't have the coin or time to collect an arsenal of pedals.
And I'm with Ash...I'd like to hear some samples...
Happy Trails
Cynical One
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Post by D2o on Jan 30, 2010 12:56:18 GMT -5
Beautiful work!
D2o
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Post by flateric on Jan 30, 2010 13:05:38 GMT -5
OK here's soime quick clips played straight out the pedal into the soundcard, pretty bare but you get an idea. www.mediafire.com/file/q1myut44bim/ts808sclip.mp3Tone knob set to 3 o' clock, gain set to about 10 o' clock first 4 soundbites are guitar (humbuckers N+B together) 1) Soft clip, hi tone selected 2) soft clip, mid tone 3) full clip, mid tone 4) full clip, phat tone (Normal default unmodded TS position would be full clip, high tone) Next is bass, again tone set to 3am, gain on about 10 am. Vol is on about 10am 1) soft clip, phat tone 2) soft clip, mid tone 3) full clip, phat tone - almost double the gain with full on 4) full clip, mid tone loses a bit of the heavier bass, gives a more aggressive edge to the o'drive |
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Post by JohnH on Jan 30, 2010 14:58:01 GMT -5
Nice work - the tones sound great, allowing that the guitar tone will be going through an amp to smooth the highs. I like the soft clip, with high tone on the guitar and phat on the bass.
How do you make your lettering for the box? my only solution for that is to get my graphically orientated wife to paint them.
cheers
John
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Post by flateric on Jan 30, 2010 15:15:24 GMT -5
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Post by cynical1 on Jan 30, 2010 16:56:53 GMT -5
Very nice. After almost 30 years of avoiding pedals for the bass now I'm looking at the error of my ways...
Thanks...after two years to gain a passing understanding of how to wire my guitars and basses now I'm back to the Net to research how to build one of these bad boys...
Again, nice work on a fantastic take on a traditional pedal.
Happy Trails
Cynical One
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