So I have been reading for a little while now and I think I am ready to try and repair my first prebuilt pedal. Not sure if it works but I purchased this pedal in hopes that I will become more familiar with testing components and making simple replacements of parts, weather it be a diode resistor ect.
When I receive this pedal in the mail I will take a few nice pictures of the board. I know its like spoon feeding me lol, but can you guys take the pictures I post and edit them with little notes so I can identify the parts in question. My goal is to take this real cheap simple distortion pedal, fix it, then mod it slowly changing parts here and there until I get more comfortable using a breadboard and doing simple little changes to its sound with mods.
My hopes in doing this is I would like to continue my hobby of fiddling with these effect pedals with my spare change in parts lol. Its really interesting and I do want to learn. I am SLOW at learning though so please be gentle ;D
The pedal is a rocktek-dir-01-distortion
(https://s14.postimg.cc/esf51e9j1/s-l1600.jpg) (https://postimg.cc/image/esf51e9j1/)
Also I haven't received the pedal yet its coming in the mail. I will post pictures of the board when I get it, thanks.
welcome to the forum, chuckusa.
you might want to ask one of the moderators to move this thread to the "building your own" section, where many many more people, everyone of them skilled at photo scribbles, will look and see and help.
while waiting for the pedal to arrive, search-up the schematic diagram - we'll ask for it, anyway.
Alright, thanks for the reply :)
Welcome!
I look forward to the guts shots. We love a nice photo of a pedal with its guts out round here...lol :)
Tom
Yer boi.
Welcome chuckusa.
I'm a slow learner too. No shame in that.
You are in the perfect place to learn at your pace, the guys here are great.
5 yrs ago I'd seen a resistor but didn't know what it did.
Thanks to the persistence of the guys I'm now cludging stuff together from what I've learnt.
A good place to learn is to look at some schematics of say transistor circuits.
Google is your friend
Common emitter.
Common collector
Breadboard them.
Small bear has a good place to learn about breadboarding.
I'm trying not to assume to much about how much you knowalready
How's your soldering.
That distortion may be an smd board. Meaning the tiny componant sizes used in mobile phones.
Then again you might get lucky and discover it all through hole.
Keeping my fingers crossed for you.
Any questions just ask and we'll do our best to help.
Quote from: Kipper4 on April 17, 2018, 01:35:48 PM
Yer boi.
Welcome chuckusa.
I'm a slow learner too. No shame in that.
You are in the perfect place to learn at your pace, the guys here are great.
5 yrs ago I'd seen a resistor but didn't know what it did.
Thanks to the persistence of the guys I'm now cludging stuff together from what I've learnt.
A good place to learn is to look at some schematics of say transistor circuits.
Google is your friend
Common emitter.
Common collector
Breadboard them.
Small bear has a good place to learn about breadboarding.
I'm trying not to assume to much about how much you knowalready
How's your soldering.
That distortion may be an smd board. Meaning the tiny componant sizes used in mobile phones.
Then again you might get lucky and discover it all through hole.
Keeping my fingers crossed for you.
Any questions just ask and we'll do our best to help.
My soldering is not too bad. I know a little about resistors capacitors and op amps. Thats really about it lol...
Quote from: ElectricDruid on April 17, 2018, 01:07:01 PM
Welcome!
I look forward to the guts shots. We love a nice photo of a pedal with its guts out round here...lol :)
Tom
Cool lol.
Hi Chuck, welcome!
One thing I'd like to add to your 'intro' - I think it might be easier to do a NEW project, like a opamp or BJT boost, rather than try to fix something already broken. If you can control what's going on, you might end up learning more with a better 'workflow' or something like that, IMO. Broken things often have stuff going on that is way out of our control, is what I mean...gremlins, things that make what SHOULD make sense seem like it doesn't...but whatever!
As long as you are enjoying what you're doing. Let us know if we can help.
A buddy of mine has a Rocktek distortion, he asked me to mod it because frankly it sounds awful. I searched for a schematic online but couldn't find one. Theoretically could've traced the circuit but more trouble than it was worth. So, good luck, and if you do find a schematic, please share!
I found this last night while hunting on google.
(https://s14.postimg.cc/tgcpqhhkt/rocktek_distortion.png) (https://postimg.cc/image/tgcpqhhkt/)
Ah - the Rocktec Distortion! Fond memories, as it was the first pedal I ever bought... I had it open a time or two, poking around before I knew anything. If I recall it's not SMD (early 80s technology).
May I ask what your skill level is? I see above you say "...I know a little about resistors capacitors and op amps. Thats really about it..." but if you've been reading and lurking you may know more than you think... Are you familiar with basic concepts of DC circuits? Can you add/subtract/divide? Can you read a schematic? Have you ever troubleshot before? Also tools - do you have a multimeter? Audio probe? Have you ever troubleshot an electric circuit?
Even if the answer to all of those is "no", don't sell yourself short. Heaven knows I is not the sharpest tool in this shed but I've learned enough to repair/mod commercial/non commercial pedals, (some without any tech-data) and tweak existing designs and pedals. Keep hanging out here - these folks know what they're doing.
If all you want to do is get your Rocktec up and running we'll get you there. If you're interested in more than that I might suggest a reference I've found quite handy over the years: "Basic Electricity and DC Circuits" by Ralph Olivia and Charles Dale - this is the book once used by Texas Instruments to train it's novice in-house technicians. Pretty easy read, covers the basics, and assumes no prior knowledge. I got mine on Amazon used for around $20. Another good and cheap reference is "Lessons in Electric Circuits" by Tony Kuphaldt - my last Google on that shows a B&N copy for $6.99. Hell - I might even have that on .pdf! Let me know if you're interested and I'll dig through the archive.
Anyway... Welcome to the asylum. Let us know what you need.
Quote from: chuckusa on April 17, 2018, 08:15:24 PM
I found this last night while hunting on google.
Thanks! Saved.
Quote from: chuckusa on April 17, 2018, 08:15:24 PM
I found this last night while hunting on google.
(https://s14.postimg.cc/tgcpqhhkt/rocktek_distortion.png) (https://postimg.cc/image/tgcpqhhkt/)
Nice work, and a good start. TBH, that circuit looks like standard stuff. Did you also come across this thread on another forum where people discuss possible mods for it?:
http://www.freestompboxes.org/viewtopic.php?f=11&t=3763&sid=ca19505aaf5682a965d713e7be4e3f32 (http://www.freestompboxes.org/viewtopic.php?f=11&t=3763&sid=ca19505aaf5682a965d713e7be4e3f32)
Quote from: pollyshero on April 17, 2018, 09:31:28 PM
Ah - the Rocktec Distortion! Fond memories, as it was the first pedal I ever bought... I had it open a time or two, poking around before I knew anything. If I recall it's not SMD (early 80s technology).
May I ask what your skill level is? I see above you say "...I know a little about resistors capacitors and op amps. Thats really about it..." but if you've been reading and lurking you may know more than you think... Are you familiar with basic concepts of DC circuits? Can you add/subtract/divide? Can you read a schematic? Have you ever troubleshot before? Also tools - do you have a multimeter? Audio probe? Have you ever troubleshot an electric circuit?
Even if the answer to all of those is "no", don't sell yourself short. Heaven knows I is not the sharpest tool in this shed but I've learned enough to repair/mod commercial/non commercial pedals, (some without any tech-data) and tweak existing designs and pedals. Keep hanging out here - these folks know what they're doing.
If all you want to do is get your Rocktec up and running we'll get you there. If you're interested in more than that I might suggest a reference I've found quite handy over the years: "Basic Electricity and DC Circuits" by Ralph Olivia and Charles Dale - this is the book once used by Texas Instruments to train it's novice in-house technicians. Pretty easy read, covers the basics, and assumes no prior knowledge. I got mine on Amazon used for around $20. Another good and cheap reference is "Lessons in Electric Circuits" by Tony Kuphaldt - my last Google on that shows a B&N copy for $6.99. Hell - I might even have that on .pdf! Let me know if you're interested and I'll dig through the archive.
Anyway... Welcome to the asylum. Let us know what you need.
Thanks for the kindness. That pdf would be cool, if you can find it. I do have a multi meter, my math is ok. I am very novice to dc circuits and the whole idea of schematic reading. I would like to get my hands dirty with this rocktek pedal and see about making it work. Im still real new to trouble shooting but I will try to soak in everything I find on this site. :icon_mrgreen:
Quote from: ElectricDruid on April 18, 2018, 05:01:38 AM
Quote from: chuckusa on April 17, 2018, 08:15:24 PM
I found this last night while hunting on google.
(https://s14.postimg.cc/tgcpqhhkt/rocktek_distortion.png) (https://postimg.cc/image/tgcpqhhkt/)
Nice work, and a good start. TBH, that circuit looks like standard stuff. Did you also come across this thread on another forum where people discuss possible mods for it?:
http://www.....org/viewtopic.php?f=11&t=3763&sid=ca19505aaf5682a965d713e7be4e3f32 (//http:///viewtopic.php?f=11&t=3763&sid=ca19505aaf5682a965d713e7be4e3f32)
I did find this schematic from another site called freestompboxes.org.
Quote from: GibsonGM on April 17, 2018, 05:35:26 PM
Hi Chuck, welcome!
One thing I'd like to add to your 'intro' - I think it might be easier to do a NEW project, like a opamp or BJT boost, rather than try to fix something already broken. If you can control what's going on, you might end up learning more with a better 'workflow' or something like that, IMO. Broken things often have stuff going on that is way out of our control, is what I mean...gremlins, things that make what SHOULD make sense seem like it doesn't...but whatever!
As long as you are enjoying what you're doing. Let us know if we can help.
Alright I will ask as I am poking along. Thanks. ;D
Quote from: thermionix on April 17, 2018, 07:05:38 PM
A buddy of mine has a Rocktek distortion, he asked me to mod it because frankly it sounds awful. I searched for a schematic online but couldn't find one. Theoretically could've traced the circuit but more trouble than it was worth. So, good luck, and if you do find a schematic, please share!
if memory serves, its the same as the arion 4 knob distortion
Often a commercial pedal that's misbehaving just has a bad solder joint on one of the jacks or the power plug. You might get this fixed in five minutes. But that's a learning experience too! Just like a "scratchy" pot... a little electronics cleaner, or worst case, replace the pot, and bob's your uncle!
But as far as learning, breadboard is where it is at. Alternatively, build a tubescreamer (lots of premade boards you can buy cheap) and socket many of the key components.
Let us know when you're ready to etch your own pcb or enclosure... that's when you know you've made it and got the bug!
Cheers!
Quote from: Beo on April 18, 2018, 10:37:36 PM
Often a commercial pedal that's misbehaving just has a bad solder joint on one of the jacks or the power plug. You might get this fixed in five minutes. But that's a learning experience too! Just like a "scratchy" pot... a little electronics cleaner, or worst case, replace the pot, and bob's your uncle!
But as far as learning, breadboard is where it is at. Alternatively, build a tubescreamer (lots of premade boards you can buy cheap) and socket many of the key components.
Let us know when you're ready to etch your own pcb or enclosure... that's when you know you've made it and got the bug!
Cheers!
Well I did order some dip 8 sockets from china and I ordered me one LM308 Op am IC chip from ebay also. Do you guys think the LM308 will fit in this pedal? I will snap some pics of it later today. I always wanted to convert a cheap pedal into a custom rat style. Then eventually make my own custom rat pedal.... 8)
Your schematic calls for a jrc4558 ( btw often the prefix can be different, lm4558. Same thing just different manufacturers.)
This is a dual op amp in a dip8 package.
I googled the pinout for you
http://www.elektropage.com/default.asp?tid=618
Your lm308 is a sIngle op amp in a dip8 package
Notice the pinout is different. So this won't be a drop in replacement part
The pinout and is on page 2 here
http://www.analog.com/media/en/technical-documentation/data-sheets/lt0108.pdf
It's always a good idea to google such things or ask here for opinions.
However having said congratulations on securing the parts for a future build.
The rat is an absolute classic.
Rich
Quote from: Kipper4 on April 19, 2018, 02:08:07 PM
Your schematic calls for a jrc4558 ( btw often the prefix can be different, lm4558. Same thing just different manufacturers.)
This is a dual op amp in a dip8 package.
I googled the pinout for you
http://www.elektropage.com/default.asp?tid=618
Your lm308 is a sIngle op amp in a dip8 package
Notice the pinout is different. So this won't be a drop in replacement part
The pinout and is on page 2 here
http://www.analog.com/media/en/technical-documentation/data-sheets/lt0108.pdf
It's always a good idea to google such things or ask here for opinions.
However having said congratulations on securing the parts for a future build.
The rat is an absolute classic.
Rich
Oh cool thanks for the help :) I will probably get me a Rat 2 to fiddle with next payday. Yea I figured at least I could have some parts for the future if they didn't drop into my ole beater rocktek lol.
Quote from: pinkjimiphoton on April 18, 2018, 09:43:54 PM
if memory serves, its the same as the arion 4 knob distortion
If memory can count, I'm thinking there's at least one difference. :icon_wink:
So I got it today. It actually works! From what I can count there are 6 clipping diodes. Them I think are what I am going to hook up to my little breadboard first to do some experimenting.
(https://s14.postimg.cc/j891n5xzx/30715601_435794746833333_777808063225659392_n.jpg) (https://postimg.cc/image/j891n5xzx/)
(https://s14.postimg.cc/xrg6ol6kd/30724634_435794763499998_6484130977382662144_n.jpg) (https://postimg.cc/image/xrg6ol6kd/)
(https://s14.postimg.cc/u7u8yrw4t/30744020_435794766833331_8624067753663266816_n.jpg) (https://postimg.cc/image/u7u8yrw4t/)
(https://s14.postimg.cc/cj2i6kk7h/31069120_435794753499999_383091240054292480_n.jpg) (https://postimg.cc/image/cj2i6kk7h/)
Schematic shows two clipping diodes, D5 and D6. The others are for non-audio purposes, mostly bypass switching. What's your impression of the sound?
I feel like most reviews on youtube said. The pedal pots have very little change on the sound. It sounds real cheap, and its not real dynamic. The distortion is thin and plain... Exactly what I thought it would sound like. I guess I am going to start farting around with them two clipping diodes. See what changes I can get with my breadboard.
Im taking baby steps lol. Can someone kinda walk me through how I am suppose to wire my hot and ground to the diode locations? I know physically how to do it, but I mean like which side of the pair do I attach the hot and cold wires to run to my breadboard and I am to take out the pair of diodes right? Im such a noob.
Quote from: chuckusa on April 20, 2018, 07:27:48 PM
Im taking baby steps lol. Can someone kinda walk me through how I am suppose to wire my hot and ground to the diode locations? I know physically how to do it, but I mean like which side of the pair do I attach the hot and cold wires to run to my breadboard and I am to take out the pair of diodes right? Im such a noob.
If you're wanting to experiment with different diodes you can
carefully remove them by desoldering. Do you have a desolder pump or desolder braid? The board looks single sided so shouldn't be to tricky to remove. Once they're out and the holes are clear of any solder i'd recommend putting some sockets in so you can easily swap in and out different diodes and see which combination you like. Look into symmetrical and asymmetrical clipping arrangements.
I usually keep a few strips of this handy, so you can make in-line sockets of any size you need. Just score it with a scalpel and gently snap a piece off.
https://www.taydaelectronics.com/30-pin-dip-sip-ic-sockets-adaptor-solder-type.html
As for what diodes to try; someone will be able to give you some exact details here, but different diodes will change the clipping characteristics. Germanium diodes have a lower clipping threshold so will distort 'softer' in theory. Silicon will likely sound a little harsher. You can also try using LEDs as they have a sound all of their own.
Other things you may want to experiment with that will be easily to try are input and output caps. If you think it sounds a little thin try increase the size of these, or play around with different values for C9 to change the frequency response of the tone pot (someone correct me if i'm wrong here)
Take everything i say with a pinch of salt, i'm only about a page ahead of you in the 'electronics 101' book.
Quote from: chuckusa on April 20, 2018, 07:27:48 PM
Im taking baby steps lol. Can someone kinda walk me through how I am suppose to wire my hot and ground to the diode locations? I know physically how to do it, but I mean like which side of the pair do I attach the hot and cold wires to run to my breadboard and I am to take out the pair of diodes right? Im such a noob.
Either way, doesn't matter in the case of these clipping diodes. There's one pointing each direction, so together as a pair there's no polarity.
Alright I will get my hands dirty soon lol. Thanks for the support!
So I found a my first sweet spot. I tried pairs of Germanium 1n34a, 1n4001, and bat41 diodes.
I found that two ger 1n34a and one bat 41 arranged like this picture I liked. Make it sound like a whole new pedal.
Also I found that if I jumped where one of the two diodes go on the pedal board, and used two leads from one other diode spot, that I could tap into the signal. I had trouble with resoldering the area and had to scratch into the board to get a good connection. But it did work for me this way.
(https://s14.postimg.cc/53w85flzh/31046327_436532850092856_3295955102631723008_n.jpg) (https://postimg.cc/image/53w85flzh/)
(https://s14.postimg.cc/8os3o4g31/31073166_436532846759523_2363128230740754432_n.jpg) (https://postimg.cc/image/8os3o4g31/)
My next question is what can I do to change the power to the signal I guess you would call it? Like over drive how it already sounds, maybe make it thicker and sizzling solo bends pulls ect? With out too many overtones or scratch? I guess what I want to do is learn how to slowly but surely change the flavor, I got the crunch down for now. But changing resistors, caps and jfets, doesnt that also change the chewyness of the tone? Where should I start?
Quote from: chuckusa on April 18, 2018, 03:28:25 PM
...That pdf would be cool, if you can find it...
[/quote]
Sorry I dropped out for a few days - been a bit busy. Anyway, I discovered I didn't have the .pdf after all BUT here's a link to download: https://www.ibiblio.org/kuphaldt/electricCircuits/DC/DC.pdf
Enjoy.
BTW - nice work so far. Congrats!
Quote from: pollyshero on April 21, 2018, 06:15:02 PM
Quote from: chuckusa on April 18, 2018, 03:28:25 PM
...That pdf would be cool, if you can find it...
Sorry I dropped out for a few days - been a bit busy. Anyway, I discovered I didn't have the .pdf after all BUT here's a link to download: https://www.ibiblio.org/kuphaldt/electricCircuits/DC/DC.pdf
Enjoy.
BTW - nice work so far. Congrats!
[/quote]
Thanks a lot!
Also can you guys recommend an alternate IC chip I can use and what sound change can I expect from each that you name please?
I read from another forum about a OPA2134 ic chip. Supose to give a marshal sound. Same chip used in the guv'nor?
Also what range capacitor and resistor value packs from ebay should I invest in so I can be ready to bring up and down values?
Quote from: chuckusa on April 21, 2018, 10:42:25 PM
Also can you guys recommend an alternate IC chip I can use and what sound change can I expect from each that you name please?
I read from another forum about a OPA2134 ic chip. Supose to give a marshal sound. Same chip used in the guv'nor?
Also what range capacitor and resistor value packs from ebay should I invest in so I can be ready to bring up and down values?
In most cases, the differences between different compatible dual opamps is VERY subtle, sometimes not even audible. You will get much more change by swapping cap and resistor values. I think the Guv'nor used a TL072. You could build one with the OPA chip and it would probably sound about the same.
I don't know what value packs are sold on Ebay, but for the long haul stock up on all the common values, resistors from maybe 10 ohms to 4.7M, caps from 10pF to 220uF or so. Look over several popular schematics and see what numbers are most common. Tayda is a good place to stock up on cheap caps and resistors. And there's a currently 15% discount code (15VOLTS) in effect until 6pm NYC time (Sunday).
Quote from: thermionix on April 22, 2018, 12:11:38 AM
Quote from: chuckusa on April 21, 2018, 10:42:25 PM
Also can you guys recommend an alternate IC chip I can use and what sound change can I expect from each that you name please?
I read from another forum about a OPA2134 ic chip. Supose to give a marshal sound. Same chip used in the guv'nor?
Also what range capacitor and resistor value packs from ebay should I invest in so I can be ready to bring up and down values?
In most cases, the differences between different compatible dual opamps is VERY subtle, sometimes not even audible. You will get much more change by swapping cap and resistor values. I think the Guv'nor used a TL072. You could build one with the OPA chip and it would probably sound about the same.
I don't know what value packs are sold on Ebay, but for the long haul stock up on all the common values, resistors from maybe 10 ohms to 4.7M, caps from 10pF to 220uF or so. Look over several popular schematics and see what numbers are most common. Tayda is a good place to stock up on cheap caps and resistors. And there's a currently 15% discount code (15VOLTS) in effect until 6pm NYC time (Sunday).
Thanks a lot for the help. I will search for these values and when im ready I will start looking about which value does what.
Ok guys I have a decent assortment of 1/4 watt resistors. Where can I start changing them out to reshape my sound and flavor? I need kinda like a little hint lol...
(https://s14.postimg.cc/4hkqvkh3x/rocktek_distortion.png) (https://postimg.cc/image/4hkqvkh3x/)
I replaced the R26 3.3k with a 100 ohm 1/4 watt resistor. It brought down the cheap overtoney tin fuzz sound that the pedal used to have. Not too much but it is becoming less cheap sounding with each mod I do.
The Marshall Guvnor, it uses a TL072 duel stage IC chip right? Will this chip drop into this Rocktek board? And will I notice a difference in sound if it does?
The TL072 will drop in and work. I wouldn't expect much of a sound change from it. IMO not worth the trouble, the 4558 is used in many fine-sounding dirt pedals. Look at what can be changed around the opamps. The feedback loops are probably good places to try some mods. Look at other circuits for ideas.
I hear you with the op amp swapping thing. Might be my ears aren't hi fi enough.
Try swapping some caps maybe C20 try bigger and smaller.
C5 C9.
Heres a neat trick. Put some other value caps in parallel with the existing values.
Crock clip leads. Then when you find the sound you like.
Google parallel cap maths. Do your sums.
Always good to practice.
Replace the nearest new value in circuit.
Bosh.
Great tips guys. Thanks a lot for the advice. I will read up on some of this stuff.