DS-1..... almost where I want it..... info please

[AC30Dirty]

hey guys, I've recently been bit by the DS-1 bug. I went to my local music store and picked one up and immediately started modding. I wound up with the mod Melenhead posted here a while back, with a couple of tweaks i came up with. IT SOUNDS ABSOLUTELY AWESOME!!!!!! I'm really digging this pedal, especially with my Kinman Woodstack equipped Stratocaster. It's almost where I want it except i think i might need to experiment with the tone stack on this baby. I'm assuming the components I'd have to mess with are R14 and C10. Is this correct? Are there any suggestion to achieve a straight up Marshall type tone stack? I have a 1.5k in R14 right now and a 0.1uf cap in C10. Would messing with these 2 components be the right way to go? Thanks

This is what i got so far:

C1, C3, C10, C11 - .047uf
C2, C8, C14 - 1uf
C5, C12, C13 - .1uf
C7- 220pf
C9 - .47uf
R17 - 5.6k
R16 - 4.7k
R39 - 22k
R11 - 4.7k
R13 - 2.4k
R14 - 1.5k
D4 - SPDT mini toggle with LED and 1n4148
D5 - LED
47pf cap in parallel across diodes

[5thumbs]

It's almost where I want it except i think i might need to experiment with the tone stack on this baby. I'm assuming the components I'd have to mess with are R14 and C10. Is this correct?

Miqbal's stock DS-1 schematic on Page 3 of the 'Build Your Own DS-1 Distortion' doc is helpful in identifying parts to mod: http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf.

There are two paths that feed into the DS-1 TONE control, with each side feeding the 1 and 3 lugs of the 100KB pot and the output to feed the LEVEL control coming off lug #2 (the wiper.)  C11 and R15 form the high-pass filter that represents the 'treble' side of the TONE control.  R16 and C12 make up the low-pass filter that represents the 'bass' side of the TONE control.  You can use Jack Orman's groovy 'Simple R-C Filter Cutoff' calculator (http://www.muzique.com/schem/filter.htm) to figure out where you want the corner frequencies of the low-pass and high-pass.  By adjusting the corner frequencies, you can tweak what gets fed into the TONE control.

Are there any suggestion to achieve a straight up Marshall type tone stack? I have a 1.5k in R14 right now and a 0.1uf cap in C10. Would messing with these 2 components be the right way to go?

FWIW, the stock value for R14 is 2k2 and C10 is 0.01μF.  If you like the sound with those components as-is, then I'd recommend leaving them and messing with C11/R15 and R16/C12 to further tweak the tone control.

If I'm not mistaken (which does happen, so corrections are welcomed), the DS-1 uses a tone circuit similar to the Big Muff Pi, which scoops the mids and see-saws the bass or treble up and down, depending on how you turn the TONE control.  The Marshall tone stack is a different tone circuit altogether, so you won't be able to replicate that circuit in the one-knob TONE control of the DS-1.

The Duncan Amps 'Tone Stack Calculator' (http://www.duncanamps.com/tsc) might help you model your tweaks so you can approximate the "Marshall" tone you're after.

Good luck!

[AC30Dirty]

Interesting...... Thanks for the info 5thumbs. You are correct on the issue of the DS-1 having a big muff type tone control. I really want the pedal to go in the direction of a Marshall type drive tone. (that's what i meant by a marshall type tone stack) I've never used a tone stack calculator before so, I wouldn't even know where to start...... sorry for the noobness If any of you guys have a link that could explain this tone stack process a little or if you care to enlighten things here on the forum I WOULD GREATLY APPRECIATE IT!!!!! Thanks

[GibsonGM]

Hi AC,

Just get the tone stack calculator, start it up, click the Marshall tab...play with the sliders to see how it works...change some parts values in there (pots are entered as K, like "100k"  and caps like nanofarads "10nf" or you'll get an error).   
Once you find a curve you like, you can model the BMP-type stack you have to approximate that response - I use electronics workbench for that.

Further, you could look at the Marshall curve, and then go to the BMP tab, and change parts there to mimic the marshall curve.   This is unscientific, and therefore easy ) Give it a go!
~Mike

[Melanhead]

Fun huh!

I have a broken DS-1 here I keep meaning to experiment with but haven't had time. I have a few more tweaks I'd like to make but haven't tried. One being removing the tone section all-together and placing a low pass filter instead and some other crazy ideas ... Modded, a DS-1 can sound better, but I've never been able to make it sound great, to me anyways ...

Have fun and don't be afraid to try things and listen to the results ...

[WGTP]

Definitely work with the Duncan Tone Stack Calculator, but notice that the 2.2K resistor in the DS-1 is not present in the BMP.  IIRC raising the 2.2k resistor should reduce the treble and lowing it should increase it.   

[MikeH]

Something to note: The tonestacks in the Duncan Tonestack Calculator are designer to work with amplifierss and I've found that they are not necessarily optimized to work with fx boxes.  They still work, just a little half assed sometimes.  You'll really need to play around with some values to get good range and useful sweep on the controls. 

[ayayay!]

If you want less shrill highs, lower R17 from 6.8k to something like 6-6.2k.  Works great!

[AC30Dirty]

i think the pedal might need a little more mids. Maybe high mids. it sounds really powerful right now and i love it i'd just like more of a vintage sound without it being muddy. Should I lower the mid resistor some more or go another route?

[5thumbs]

i think the pedal might need a little more mids. Maybe high mids. it sounds really powerful right now and i love it i'd just like more of a vintage sound without it being muddy. Should I lower the mid resistor some more or go another route?

In stock configuration, the high-pass filter that feeds the treble side of the TONE control has a corner frequency of 3290Hz.  If you want more upper mids to be passed, you could either decrease the R15 resistor or you could increase the value of the C11 capacitor.  For instance, if you changed C11 from 0.022μF to 0.033μF, you would lower the corner frequency of the high-pass filter to 2193Hz.  That would pass more upper-mids through the TONE control.  Once again, you could use Jack's R-C calculator (http://www.muzique.com/schem/filter.htm) to figure out the corner frequency sweet-spot you want for the high-pass and tweak until your ears are happy.

If you want to tweak the R15 resistor instead, you could put a 5-10K trimpot in C15 and dial in the upper-mids exactly how you want.  Another option would be to temporarily install a 5-10K pot in R15, dial in the sound you want, pull the pot and measure its resistance, and then replace R15 with a fixed resistor of equivalent value.

[AC30Dirty]

If you want to tweak the R15 resistor instead, you could put a 5-10K trimpot in C15 and dial in the upper-mids exactly how you want.  Another option would be to temporarily install a 5-10K pot in R15, dial in the sound you want, pull the pot and measure its resistance, and then replace R15 with a fixed resistor of equivalent value.

That's exactly what i was thinking of doing. I actually had a last minute gig last nite and thought I would give the pedal a whirl to see how it would react in the band mix. Surprisingly, it cut through quite well. I sounded really similar to my Dual Rectifier in Ch.2 Vintage mode. I was thinking at the gig that it would be cool to add and entire eq section to this baby. A bass, mid, treble control have the tone pot act as a presence control. I think that would be the ultimate in tweakability. Do you guys think it can be done??

[AC30Dirty]

well, I took out R16 and replaces it with a 5k pot and now i have total USEABLE control over the mids/low mids. I like having this knob there so much that i have just decided to keep it like this. I also placed a 10k pot on R17 to see if i could tweak the high frequency and I believe i've found my SWEET SPOT for my particular rig. I can't measure the pot though cause my multimeter is at a friends house. I'll probably pick it up today. Where could i do something like what i've done to control the bass???

[5thumbs]

well, I took out R16 and replaces it with a 5k pot and now i have total USEABLE control over the mids/low mids. I like having this knob there so much that i have just decided to keep it like this. I also placed a 10k pot on R17 to see if i could tweak the high frequency and I believe i've found my SWEET SPOT for my particular rig.

Congrats.

Where could i do something like what i've done to control the bass???

Do you mean the lower-mids or the bass?  The "bass" frequencies passed in the stock DS-1 are about 66Hz to around 234Hz in your configuration.

By decreasing R16 to 5K (max on the pot), you've slightly raised the corner frequency of the low-pass filter that feeds the bass side of the TONE control to 289-354Hz (giving a 10% variance on a given pot) when the pot is at max resistance.  This by itself will feed a little more lower-mids into your signal.  When at minimum resistance, you are effectively removing the mid-scoop altogether, allowing everything from 66Hz on up past 20KHz to pass through the bass side of the TONE control.  To preserve the mid-scoop, you could put a fixed resistor in series with the pot, which will allow you to set a corner-frequency below that of the high-pass filter feeding the treble side of the TONE control (overlapping the two X-pass filters would likely reduce the effect of the TONE control as you pan it.)  For instance, if you put a 470-ohm resistor in series with the R16 pot, you'd fix the max corner frequency at 3388Hz, which is pretty close to the 3290Hz corner frequency of the stock high-pass filter.  This would give you a sweep in the lower-mids from 267Hz (almost-stock) to 3388Hz (470-ohm+5K pot+10% potential pot variance.)

If you're looking to pass more lows into the whole circuit, I think you'll have to increase the bass frequencies passed into the tone circuit by increasing the capacitance of the series decoupling caps (C1, C2, C3, C5, C9, etc.).  Be warned that increasing the capacitance of C2, C3 and C5 can sometimes lead to a "flabby" or "fuzzy" distortion because you are passing more bass frequencies into the clipping circuit.  Others reading this might have better guidance as to how to increase the bass in a DS-1 without getting a "flabby" distortion as a result.  (It is possible, but I'm no expert on that topic.)

[AC30Dirty]

hey 5thumbs and everyone else here...... it's not that i don't have enough bass (with the mods i've done I actually get a nice punch in the gut) I was just wondering if there was a certain resistor i could swap out for a pot to make the bass tweakable on the fly? Either way, the pedal is sounding pretty good at this point. I can get tones ranging from Alice In Chains Dirt album to modern aggresive rock type tones (not metal) think Fuel's Something Like Human album. I'm gonna try the resistor in series with the mid pot in R16 as well. I'll maybe try and post some clips soon!!!! Thanks to everyone here and if you have any more suggestions or ideas feel free to send them my way.

[WGTP]

Gus proposed a variable hi-pass filter in another thread and I redrew his suggestion.   

http://www.aronnelson.com/gallery/main.php/v/WGTP/Gus.GIF.html

[5thumbs]

hey 5thumbs and everyone else here...... it's not that i don't have enough bass (with the mods i've done I actually get a nice punch in the gut) I was just wondering if there was a certain resistor i could swap out for a pot to make the bass tweakable on the fly?

WGTP is on the right idea for that tweak, IMO.  If you put a switchable variable high-pass filter (DPDT on-off w/series cap+pot to ground on one side, bypass on the other) in series before your R16 fixed resistor/pot combo AND set the corner frequency for this high-pass so that it only sweeps between say 60Hz and 200Hz, you would have a sweepable bass-cut filter, in addition to your sweepable mid-range controls.  You'd use the R16 holes as the "in" and "out" of this network, so no PCB mods would be necessary.

A better idea might be to get a EQ stomp box and configure it for bass cut.  Put it before your DS-1 and you could stomp the bass cut on/off as you desired.  With all the pots you're working with in your DS-1, you might have a challenge fitting more pots and switches into the tight space of the enclosure.  My $0.02.

[AC30Dirty]

very true 5thumbs. I've made some changes from the previous mods.....

C11- .1uf
R17- 4.7K
R11- 22K
R16- 5K pot
C4- 470pf
470pf cap in parallel with C10
R40- removed

with all these additional changes this pedal is pretty versatile. The .1uf in C11 gave me a nice mid frequency range in conjunction with 5k pot; to tweak tones from classic mid heavy rock to scooped (but not drastically) moder rock tones. By removing R40 the drive was able to smooth out a little bit as well. Although, I'm going to remove the IC altogether and put a burrbrown chip in it to see what kind of results that will give me. Does and IC swap really make a difference in this circuit. Monte Allums over on his website sells an adaptor kit I'm gonna buy and try. The bass is actually pretty prominent as well. I'm not introducing as much bass as what melanhead suggested on his mod but for my particular rig, it works really well. I can actually feel the notes on the bass side through my 4x12 Mesa cab really well. More experimentation to come.... I'll keep you guys posted. Thanks for all the suggestions.

[5thumbs]

I'm going to remove the IC altogether and put a burrbrown chip in it to see what kind of results that will give me. Does and IC swap really make a difference in this circuit. Monte Allums over on his website sells an adaptor kit I'm gonna buy and try.

I use those adapter boards all the time and they work great.  The Burr Brown OPA1234PA is my personal favorite in the DS-1, but miqbal told me the the LM358N is pretty close to the OPA2134PA.

If you need more headroom over the adapter-mounted op amp, you can install 8 Mill-Max in-line sockets in the PCB, then install the adapter and gently bend the adapter over to get more clearance.

I've never used Monte's adapter board (always either made my own or bought them from Cimarron Technology: http://www.cimarrontechnology.com/index.asp?PageAction=VIEWPROD&ProdID=34), but his adapter board looks identical to the Brown Dog-brand adapter, even down to the option of using a surface-mount SO8 op amp on it.

[AC30Dirty]

im picking up a radio station from the pedal now. Even when the pedal is off. I know its the pedal cause i ran my guitar straight to the amp and the station is not there. Have any of you guys experienced this when modding your DS-1?

hey 5thumbs, how does the burrbrown chip compare in sound to the IC the stock pedal has??? Does it change the tone of the pedal over all or is it not that big of a difference??

[5thumbs]

im picking up a radio station from the pedal now. Even when the pedal is off. I know its the pedal cause i ran my guitar straight to the amp and the station is not there. Have any of you guys experienced this when modding your DS-1?

I've had this happen a few times, but usually with long cables with rather cheesy shield wire coverage.  Does it happen with different/shorter cables? 

hey 5thumbs, how does the burrbrown chip compare in sound to the IC the stock pedal has??? Does it change the tone of the pedal over all or is it not that big of a difference??

Depends upon which IC is in your DS-1.  The OPA2134PA is smoother than the stock chips and provides more definition to pick attack and other nuances.  The M5223AL has a "yang"-ey quality to it that goes away with the OPA2134PA.  The NJM3404L (the new one) loses the "yang" and sounds close to the M5218AL found in other pedals...fairly flat-EQ-sounding, reasonable definition...but not as smooth as the OPA2134PA.

I'm sure others will chime in with their DS-1 op amp favorites (which always happens after I praise the OPA2134PA over other op amps in the DS-1. )  There are other op amps that sound good in the DS-1, but I haven't tried one yet that I like better than the OPA2134PA.  The new stock chip, NJM3404L, is actually not bad...and some day, I'll get around to trying a LM358N as well.  Until then, you now know my biased opinion on replacement DS-1 op amps.