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
Quote from: AC30Dirty on May 05, 2008, 08:02:31 PM
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.
Quote from: AC30Dirty on May 05, 2008, 08:02:31 PM
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!
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 :icon_lol: 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
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 :o) Give it a go!
~Mike
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 ...
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. :icon_cool:
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.
If you want less shrill highs, lower R17 from 6.8k to something like 6-6.2k. Works great!
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????
Quote from: AC30Dirty on May 06, 2008, 07:57:25 PM
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.
QuoteIf 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??
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???
Quote from: AC30Dirty on May 07, 2008, 08:49:54 PM
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. :)
Quote from: AC30Dirty on May 07, 2008, 08:49:54 PM
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.)
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. ;D
Gus proposed a variable hi-pass filter in another thread and I redrew his suggestion. :icon_cool:
http://www.aronnelson.com/gallery/main.php/v/WGTP/Gus.GIF.html
Quote from: AC30Dirty on May 08, 2008, 09:29:49 AM
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. :)
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.
Quote from: AC30Dirty on May 08, 2008, 08:19:28 PM
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.
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??
Quote from: AC30Dirty on May 09, 2008, 01:16:11 AM
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?
Quote from: AC30Dirty on May 09, 2008, 01:16:11 AM
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. :)
QuoteI'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?
It happens with any cables i use. It happens in my pedalboad chain and by itself. none of the other pedals on the board pick it up. :-\
Quote from: AC30Dirty on May 09, 2008, 01:16:11 AM
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????
From searching other posts on this topic, it might be a case capacitance/grounding issue. Suggestions range from putting a 22-47pF cap from the PCB input (not input jack) to ground, as well as checking all the grounds for continuity and possibly even using shielded wire from the input jack to the PCB.
Here's the info from the 'DIY FAQ' (http://www.diystompboxes.com/wiki/index.php?title=DIY_FAQ) on this site:
"misc - I am picking up radio stations, how can I stop this?
From Eric Hensel: A 47pf cap to,ground, after the input cap will probably do it --you can adjust this up or down --higher values will start to cut treble. use the lowest value that works.
From Zachary Vex:
Mount the pc board as close as you can physically to the metal box. this will serve as a ground plane to reduce the heterodyning that can pick up rf. don't let the input and output wires cross... make sure the layout doesn't allow input and output connections to get too close to each other. if you can, solder in ground connections around (near) the sensitive input circuitry. if rf is being picked up by rectification, these fixes won't help, but if it is being picked up due to beat frequencies generated by heterodyning (internal rf oscillation in the circuit beating against rf from radio stations) you can get rid of it through the use of careful layout and grounding to reduce oscillation.
You might try using miniature shielded cable inside of the enclosure for the input to the board too."
Here are some other threads that discuss this problem and potential solutions:
http://www.diystompboxes.com/smfforum/index.php?topic=38267.0
http://www.diystompboxes.com/smfforum/index.php?topic=62829.0
And a short blurb on GEOFEX on the topic:
http://www.geofex.com/fxdebug/picksupradio.htm
This mod looks interesting:
http://www.muzique.com/news/?p=95
Thanx guys, for the link hook up!!!!! I had gigs this past friday and saturday so, I haven't really been abel to mess around with the pedal. I'll get around to it this week for sure though. I'm definetely gonna try that DS-1 fat mod. If it does what it says it does it just might be the icing on my cake for this pedal!!!! ;D
Quote from: erikm5150 on May 10, 2008, 01:31:01 PM
This mod looks interesting:
http://www.muzique.com/news/?p=95
Thanks for the link, Erik! I've not heard of that one before, but it looks too simple and too good not to try at least once. If you put the resistors on a DPDT and you can A/B then with a flick of a switch...and if you like that switch thing, mount the switch and keep that feature around for good.
well..... i tried out the mod to that link posted by erikm5150 and the pedal wouldn't work, so I went back to stock values. it was weird.... maybe it to a different DS-1 version or something... ???
Quote from: AC30Dirty on May 13, 2008, 02:49:22 PM
well..... i tried out the mod to that link posted by erikm5150 and the pedal wouldn't work, so I went back to stock values. it was weird.... maybe it to a different DS-1 version or something... ???
In the section of the circuit cited by Jack Orman, the only difference between the pre-1994 "vintage" DS-1 and the post-1994 variants is C5 (other than Jack's changes to R6 and R9, of course.) Jack has the pre-1994 value of 0.47μF in C5, where the post-1994 pedals have 0.068μF in C5. That difference in itself shouldn't make a huge difference, so there might be something else causing Dead Pedal Syndrome here.
I have a DS-1 that is in-progress on the "Mondo-MIJ" mod, but hasn't gotten the updated clipping network yet. (Given that, you can think of it as a hi-fi version of a 'MIJ-Mod'-ed DS-1.) I'll try the resistor swap on that pedal tonight and report back with my results. FWIW, all of the MIJ-type mods have 0.47μF in C5, so on paper, they should match up with the diagram Jack provided.
Thanks,
Brett
hey 5thumbs, what is this MIJ modded DS-1 your talking about??? I've never heard of that. By the way, on my pedal C5 is an electrolytic cap that read 47uf not .47uf or 4.7uf That seems REALLY BIG!!!! :icon_eek:
ok.... so here is what i tweaked with tonight..... i changed C3 to .033uf and this caused the pedal to open up consideralby. No really noticeable compression but, theres still some there. Next I C12 with a .047uf cap to go along with the 5k pot.... now the pedal can really be tweaked on the fly quite nicely. I also increased R13 from 2.2K to 3.3K for a little bit less drive. The pedal doesn't feedback now at MAX GAIN and I still have plenty of drive to work with and the sustain is still there. I did notice however, since i chaged C3 to .033uf it seems the pedal has lost a little punch. What spot on the pedal could I alter to bring the punch back up??? I was thinking C9. Would this be the way to go???
Quote from: AC30Dirty on May 13, 2008, 07:38:56 PM
hey 5thumbs, what is this MIJ modded DS-1 your talking about??? I've never heard of that.
The 'MIJ Mod' is a mod I developed to make the post-1994 DS-1 pedals sound like the pre-1994 DS-1 pedals by changing critical soundpath components back to the values in the pre-1994 DS-1 pedals. The MIJ-Mod is discussed on Page 16 of the 'Build Your Own DS-1 Distortion' doc I co-wrote with miqbal: http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf. (If you want to know why I selected the components in the MIJ-Mod, read Pages 24-26 and I try to explain all the component differences between pre- and post-1994 DS-1 pedals. It was my way of "showing my work.")
The 'MIJ-Plus' mod (Page 17) is basically the MIJ-Mod with a tweak to the D4/D5 clipping diodes, done largely to reduce fizz that was more apparent with the later op amps than it was with the TA7136P op amp in the pre-1994 DS-1.
I A/B tested my MIJ-Mod and MIJ-Plus against my pre-1994, M.I.J. DS-1 and they sound
very similar. I know it might be heretical to say this, but I think the post-1994 DS-1 pedals with any of the MIJ mods sound better than the original. I'm keeping the pre-1994 for its historical value (plus I got it for $75 in good condition.) It's also useful for settling arguments with folks who insist the pre-1994 DS-1 pedals can't be beat. :)
The 'Mondo-MIJ' (Pages 18-21) is basically the hi-fi version of the MIJ-Mod with a rather complex clipping network installed in place of D4/D5. It's the best-sounding of the lot, but the Mondo-MIJ is a bit of a pain in the tuchus to build. So one of these days, I'll get around to finishing the 'EZ-Mondo' mod, which will get the best parts of the Mondo-MIJ sound in a mod one can do in under an hour.
All that and more is in the doc (http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf), so give it a read when you get the chance.
Quote from: 5thumbs on May 13, 2008, 04:37:14 PM
I have a DS-1 that is in-progress on the "Mondo-MIJ" mod, but hasn't gotten the updated clipping network yet. (Given that, you can think of it as a hi-fi version of a 'MIJ-Mod'-ed DS-1.) I'll try the resistor swap on that pedal tonight and report back with my results. FWIW, all of the MIJ-type mods have 0.47μF in C5, so on paper, they should match up with the diagram Jack provided.
OK, I tried out Jack's DS-1 "Fat" mod this morning. (It doesn't kill the pedal, BTW.) If I had to characterize this mod by another name, I'd call it the "mud" mod. It reduces the highs considerably, which can be useful. It also causes a boost in perceived bass and mids, due to the aforementioned treble cut. Unfortunately for my ears, it cuts them a bit too much, causing a loss of articulation. If you're going for more of a fuzz-type sound, then Jack's "Fat" mod would be pretty groovy.
I personally prefer more note articulation when going for a flat, non-scooped DS-1. Given that, I'll stick with my PHLAT Mod (Page 22 in the http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf doc) to bump up the mids (actually, remove the mid-scoop in the TONE control) and keep the highs crisp.
Either way, Jack's "Fat" mod is interesting and very easy to do. I'd encourage the curious to give it a shot...if you're going for fuzz tones with your DS-1, then this mod could meet your need.
Good luck!
hey 5thumbs, I can't seem to open up your pdf. file on the MIJ mods. I really wanna read up on it. Even if I download it, it'll tell me that the file is incomplete or corrupted. :(
By the way..... The DS-1 im working on right now has an IC chip that reads
NJM3404AL
JRC G008A
Quote from: AC30Dirty on May 14, 2008, 10:48:46 AM
hey 5thumbs, I can't seem to open up your pdf. file on the MIJ mods. I really wanna read up on it. Even if I download it, it'll tell me that the file is incomplete or corrupted. :(
I just downloaded the doc from http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf and it worked OK for me. Curious...can someone else here try downloading it and see if it works for them?
AC30Dirty, if you PM me with your e-mail address, I'll send you the latest PDF copy of the doc. :)
Quote from: AC30Dirty on May 14, 2008, 10:48:46 AM
By the way..... The DS-1 im working on right now has an IC chip that reads
NJM3404AL
JRC G008A
That's the latest op amp in the DS-1. I've never had the chance to try the BA728N (the ROHM op amp first used when they redesigned the DS-1 in 1994) in a DS-1, so I can't offer an opinion on it. However, I've played a bunch of DS-1 pedals with the M5223AL op amp in it and a handful of ones with the NJM3404AL in them. The NJM3404AL isn't as good as some replacements (e.g., OPA2134PA, LM358N, etc.), but it is better than the M5223AL. The sample 'MIJ-Plus' pedal I keep around has the NJM3404AL because I liked it better than the M5223AL -and- the NJM3404AL is technically a stock op amp (which is important for testing purposes.)
BOSS used the M5223AL from around 2000 until 2007, when they switched to the NJM3404AL. Fortunately, the replacement op amp sounds better, so it's a win-win for BOSS.
I just downloaded the pdf and it worked fine ...
Quote from: Melanhead on May 15, 2008, 06:06:00 AM
I just downloaded the pdf and it worked fine ...
Cool. Thanks for checking for me, Bob.
I e-mailed the doc to AC30Dirty. If anyone else can't download it, PM me with your e-mail address and I'll send it to you directly. FYI for those of you getting the doc via e-mail...when I update the doc, I'll post it in the same location, but drop an update into this thread: http://www.diystompboxes.com/smfforum/index.php?topic=64731.0.
Quote from: 5thumbs on May 14, 2008, 10:11:28 AM
OK, I tried out Jack's DS-1 "Fat" mod this morning. (It doesn't kill the pedal, BTW.) If I had to characterize this mod by another name, I'd call it the "mud" mod. It reduces the highs considerably, which can be useful. It also causes a boost in perceived bass and mids, due to the aforementioned treble cut. Unfortunately for my ears, it cuts them a bit too much, causing a loss of articulation. If you're going for more of a fuzz-type sound, then Jack's "Fat" mod would be pretty groovy.
I personally prefer more note articulation when going for a flat, non-scooped DS-1. Given that, I'll stick with my PHLAT Mod (Page 22 in the http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf doc) to bump up the mids (actually, remove the mid-scoop in the TONE control) and keep the highs crisp.
Either way, Jack's "Fat" mod is interesting and very easy to do. I'd encourage the curious to give it a shot...if you're going for fuzz tones with your DS-1, then this mod could meet your need.
(Boy it's weird quoting myself in a response.)
I think I owe Jack Orman an apology for the "mud mod" comment above. I took one of my lesser-used DS-1 pedals and reworked it today to combine Jack's "Fat" mod, the components from the Mondo-MIJ (minus the clipping network) and added in a BS170 MOSFET clipping arrangement and ended up with a killer sounding mod!
The pedal ended up being identical to the one I tested with before, but by increasing the proximity-to-clip from the stock 1N4148-type diodes to the MOSFETs really cleared up the mud/fuzz and produced a distortion that reminds me of the few odd Plexis I've played in my lifetime. (My ToneLabSE models the '68 Plexi, but it's not quite the same as the real thing.) I've tried other "plexi" mods for the DS-1, but was never very happy with the loss of note articulation that those mods ended up with. They all seem to get the growling bottom end right, but I was never happy with the top end. That's why I started with the Mondo-MIJ components...good note articulation with lots of detail and sustain.
I'm going to add this setup as a new mod (the 'VR-MIJ') in the BYODD doc tonight. Jack was right (as usual), so I've got to give yet more kudos to the man. :)
Thanks for sending the doc. to my email!!!! I was able to download it and open it up. VERY INTERSTING AND INFORMATIVE stuff you got there 5thumbs. After reading the entire document I converted my pedal back to stock and performed the MIJ MONDO mod (leaving the cliiping mods out because I don't have that type of transistor) and the pedal sounds pretty good. I'm messing again with the high and low pass filters and getting some great results. I'm gonna be tweaking most of the night tonite and see what I end up liking. What other type of transistors can I substitute in the clipping section???? I'm not to familiar with transistors so some different models would help. Thanks
ok.... this maybe a dumb question for some of you guys but, I need to ask it.....what does the whole corner frequency term mean??? The higher the number the more lows or highs are introduced depending on what you pluging in to the frequecy calculator???? If R16 and C12 make the low pass filter and R15 and C11 make the high pass filter what do C10 and R14 control????? Does the higher the total number for the combination of R16 and C12 mean it will result in more bass or is it the opposite???? I'm really trying to understand this stuff but, I feel a bit lost!!!!!! :-\
Quote from: AC30Dirty on May 15, 2008, 08:04:30 PM
ok.... this maybe a dumb question for some of you guys but, I need to ask it.....what does the whole corner frequency term mean??? The higher the number the more lows or highs are introduced depending on what you pluging in to the frequecy calculator???? If R16 and C12 make the low pass filter and R15 and C11 make the high pass filter what do C10 and R14 control????? Does the higher the total number for the combination of R16 and C12 mean it will result in more bass or is it the opposite???? I'm really trying to understand this stuff but, I feel a bit lost!!!!!! :-\
Not a dumb question to me, as I don't know the answer myself. I suspect R14 is working with C9 (the DC decoupling cap after the op amp) to reduce RFI pickup. (I read R.G. talking about that somewhere on this board recently, but I can't recall where.) As for C10, I always figured was a cap shunt to darken the tone a bit after all the boost stages and the diode clipping.
Hopefully others wiser than I can provide a more technically-grounded explanation as to what R14 and C10 do in this circuit, but those are my S.W.A.G.s.
As for more light reading on low/high pass filters and corner frequencies, you might check out: http://en.wikipedia.org/wiki/Cutoff_frequency, http://en.wikipedia.org/wiki/Low-pass_filter, http://en.wikipedia.org/wiki/High-pass_filter and I'm sure R.G. has some good stuff on it over at GEOFEX.
Thanks 5thumbs..... I can't begin to tell you how much you've helped me with this pedal!!!!! ;D So.... after about an hour or two of tweaking and reading this is what I have my pedal modded to.....
C1, C11, C12, C13- .1uf
C2- 1uf
C3, C10- .047uf
C4- 330pf
C7- 220pf
C5, C8, C9- .47uf
R16- 4.7k
R17- 5.1k
R14- 6.8k
R13- 2.2k
The diodes are stock right now but, i need to experiment with that. Even with stock diodes this pedal is very useful now. I able to achieve tones ranging from Rush, Iron Maiden, Pink Floyd, to Alice In Chains, Weezer, other Marshally type stuff. I do however like it for more vintage rock type stuff but, thats what I was going for.
MORE STILL TO COME!!!!!!!! :icon_twisted:
Quote from: AC30Dirty on May 15, 2008, 07:28:51 PM
Thanks for sending the doc. to my email!!!! I was able to download it and open it up. VERY INTERSTING AND INFORMATIVE stuff you got there 5thumbs. After reading the entire document I converted my pedal back to stock and performed the MIJ MONDO mod (leaving the cliiping mods out because I don't have that type of transistor) and the pedal sounds pretty good. I'm messing again with the high and low pass filters and getting some great results. I'm gonna be tweaking most of the night tonite and see what I end up liking. What other type of transistors can I substitute in the clipping section???? I'm not to familiar with transistors so some different models would help. Thanks
You don't need a 2N3859A to do the clipping network in the Mondo-MIJ. I've used scrap 2SC1815s before (same pinout as the 2N3859A), but really, all you need is a NPN silicon transistor. 2N3904/2N5088/2N5089/2SC2240/2SC945/2SC2458/NTE85/BC549/BC559/etc....all of these and more should work the same in this application. Just look at the datasheet for the transistor so you can locate the Base and Emitter pins. Remove the Collector and use the Base as the anode (+) and the Emitter as the cathode (-). The only silicon transistors I can think of that you should avoid are some of the low-hfe silicon transistors like the 2N3440, as they clip at a much lower voltage than most other silicon transistors.
If you don't want to mess with the clipping network of the Mondo-MIJ, you could use the clippers I put in the VR-MIJ. (I'm making the doc updates tonight and will send it to you when I'm done.) I used a BS170 MOSFET with Gate and Drain soldered together, then put a 1N34A diode on the Source (with the line on the diode pointing toward the BS170.) You use the 1N34A side as the anode (+) and the BS170 G+D as the cathode (-). You then install it like you would other diodes in D4/D5. It's a different sound than the Mondo-MIJ clipping network, but it's a lot easier to do.
I've not come across another clipping arrangement (yet) that sounds like the one in the Mondo-MIJ. The VR-MIJ clipping arrangement sounds really good as well, but different. (I can see why folks are going nuts over MOSFET clippers. They're easy to do and sound quite good.) The clipping network in the Mondo-MIJ sounds "heavier" when pushed hard, but the VR-MIJ sounds more "natural", almost tube-like (to use that overused term.) You might bear that in mind as you pick your clippers.
hey 5thumbs, would a MPF102 transistor work well for the clipping section???
Quote from: AC30Dirty on May 21, 2008, 04:00:01 PM
hey 5thumbs, would a MPF102 transistor work well for the clipping section???
The MPF102 is a n-channel JFET, not a bipolar transistor. I've only tried NPN bipolar transistors, so I can't offer any advice on how an n-channel JFET would work in the Mondo-MIJ. With the JFET, you'd tie the Gate and Source together, then use the Drain as the other end of the "diode". I've never used a JFET as a clipper (yet), so I'm not sure about the polarity of the JFET "diode", but you should be able to figure that out pretty quickly with your DMM.
Another thing to consider is the clipping threshold of the MPF102. The majority of Si NPN bipolars (Base->Emitter) I tested clipped between 650-700mV. You might want to test the MPF102 configured as above to see what its clipping threshold is. If it's different from the 650-700mV of the NPN bipolars, you might end up with a groovy sound, but different than I ended up with. Let your ears be your guide there. :)
Hi Brett i read alot of your build your own ds1 . . . i would to ask if you'd tried the lm358n as replacement of m5223al?