I got my hands on an SHO and I love it... except for the crackle when I turn the knob. Is there a way to fix that? It makes my amp sound horrible if I adjust the volume.
Is it even fixable? Or is the crackle part of the design?
Thanks!
That is just the way it is.
if you mean that it crackles when you turn the knob, that probably means you need to replace the pot. make sure you match it up with the right
type and value, and that'll be it.
Quote from: caseyif you mean that it crackles when you turn the knob, that probably means you need to replace the pot.
Normally that would be the case, but as one might guess from a knob labeled "crackle OK", the crackle is intrinsic to the SHO. Just don't adjust the volume knob and you should be OK! :wink: :lol: (just kidding). I'd have Z. vex do any modifications if it were my pedal, strictly from a resale point of view, but I'm not sure this is offered as a *mod*.
Kerry M
the crackle is intrinsic to the design, as it is varying the DC bias to ground. If you look at this schematic from AMZ, you can see a DC blocking cap in series with the gain control, which eliminates crackle. This mod should be fairly simple to achieve on the SHO.
http://www.muzique.com/schem/mosfet.htm
me thinx Z wudda had decrackled it himself, if possible...
Hmm... well, thanks for the responses y'all. I guess I'll just learn to not adjust the level while playing... (can't sell it since it was a b'day present)
other than that how are you liking it? i'd love to get my hands on one of these :P
I don't know the exact electronics of the preamp, but it is clear the Crackle OK pot sets some bias and has DC across it which cannot be removed easily without affecting the gain/frequency response of the thing.
I think I DO have a solution, however, just send me USD 250 and I'll disclose it...
No, just kidding :lol:
I imagine that you could add to your box a momentary pushbutton that places a capacitor across the crackling pot, so you just press the pushbutton and at the same time adjust the knob. This will affect the frequency response while it is being pressed, but at least you shouldn't hear the crackling, which can be annoying and disturbing, especially when playing in a band situation.
Following image illustrates the general idea:
(http://tinypic.com/21pt9f)
http://tinypic.com/view.html?pic=21pt9f
Hope I get a complimentary Seek-wah from Mr. Z... :lol:
The Crackle is OK. :D It's supposed to crackle.
Isn't it cool when it crackles?
How can I add crackle to an existing pedal? :)
I'm sure that Mr. Vex has it that way for a reason...
Quote from: Alex CHow can I add crackle to an existing pedal? :)
throw out a blocking cap... :lol:
One way to reduce crackle is to replace the pot with a conductive plastic unit.
If you want to add crackle..... :lol: find an emitter (or collector) resistor somewhere which is touching the audio path.... replace it with one of maybe 50 to 75% of the stock value and put a pot in series with it so you can adjust from 50% to maybe 200% of stock value. The lower quality the pot, the more crackle you'll get.
Please leave it as it is. It's a hell of a booster...the best i've ever tried. i could finally get one...the design is so clever. The pot has some dc bias in it, and there is no way to add a cap or anything to solve it. There's no way for me to tell you more because i respect Zachary, and i would be telling you the tricky part of the circuit. Just go to zvex page, and read what it says about this...and a 60s console preamp...check some schems for that...and you'll get what i mean.
Quote from: swtPlease leave it as it is. It's a hell of a booster...the best i've ever tried...
I couldn't agree more. I love my SHO.
Mod your Boss pedals, leave the Zvex ones alone. :wink:
Even when there is DC running thru the contact, some pots are much quieter than others.
Maybe (I havn't tried this) one of the conductive plastic style pots would be quieter? Hell, for all I know, maybe lubricating the pot would help???
crp
clev·er    P   Pronunciation Key  (klvr)
adj. clev·er·er, clev·er·est
1] Mentally quick and original; bright
hey, i didn't write it... i just looked it up. 8^P
crp
Quote from: Torchycrp
care to explain to the rest of us? you've used that crp response on many previous occasions.
Crisis Response Plan ?
RDV
Can't Respond Politely?
Completely Removed Post...
Torchy`s on the run...
sumthin`musta p*ssed him *ff :shock: :roll:
farewell veroboards...
i think cause that other fella started making veroboards too...i could be wrong. i would think though that it would be a compliment to him.
i dont know though, cause he just posted a while a go, and it was another "crp" thing....
Peter or Aron... any ideas?
Quote from: caseyi think cause that other fella started making veroboards too...i could be wrong. i would think though that it would be a compliment to him.
dont know why that'd make him mad, considering we've both been making them for a long time...we even talked about putting a website up with both our boards....
something else must've set him off....
anyway, whatever it is Torchy...i hope it works its way out of your system soon....
best regards,
andy
Quote from: DragonflyQuote from: caseyi think cause that other fella started making veroboards too...i could be wrong. i would think though that it would be a compliment to him.
dont know why that'd make him mad, considering we've both been making them for a long time...we even talked about putting a website up with both our boards....
something else must've set him off....
anyway, whatever it is Torchy...i hope it works its way out of your system soon....
best regards,
andy
yeah, but i think there is something wrong with the board, cause he just posted and it showed up that way.....
he wouldnt post and then turn around and completely remove it....?
i dunno.
:?:
Could you add a simple volume control to the SHO without radically changing the tone?
Following with the "keep it simple" philosophy, you can simply add a momentary pushbutton that shorts out the OUTPUT jack of the SHO while you adjust the gain (i.e. crackle OK). This should work independently of the internal electronics of the SHO.
To avoid damaging things, place a 100 ohm resistor in series with the pushbutton. This should reduce output level significantly, thus masking the crackling while you move to pot.
Regards,
STM
Man, the EDIT function is gone!
Edit to the above post: you can label the pushbutton "MUTE" :wink:
STM
Boy, you can also use a N.C. (normally closed) pushbutton in series with the OUTPUT to implement a MUTE function! :idea:
I'm pretty sure Zachary Vex evaluated all these options while developing the SHO, and probaly concluded the MUTE button was a "hard sell" in comparison to the "vintage" crackling of the pot.
Regards,
STM.
I think it would be simpler to servo the source resistor with an LED/dual LDR like the Vactec VT5C3/2.
You make your gain control be a pot with a reference voltage across it, the wiper to the (+) input of an opamp. The opamp output goes to the LED, and the feedback comes from a resistor/one of the LDRs. The other LDR tracks the one being set to equal the pot voltage, and is used to set the gain.
At least I think that's what might happen, as I really, really don't know what's inside a SHO. 8-)
It is a good idea for a rack unit design. On a stompbox parts count would increase significantly as well as power consumption due to additional electronics and two extra lit LEDs.
Quote from: R.G.I think it would be simpler to servo the source resistor with an LED/dual LDR like the Vactec VT5C3/2.
You make your gain control be a pot with a reference voltage across it, the wiper to the (+) input of an opamp. The opamp output goes to the LED, and the feedback comes from a resistor/one of the LDRs. The other LDR tracks the one being set to equal the pot voltage, and is used to set the gain.
At least I think that's what might happen, as I really, really don't know what's inside a SHO. 8-)
yeah, i considered this particular option, but the minimum resistance is still too high, leaving out the highest-gain setting on the SHO, which is where the fun is for some people. 8^) using a cap as an AC bypass on the source causes changes to both the biasing of the SHO and the frequency response, plus it limits the gain, once again... in my experiments, the AC bypass cap method yielded a maximum gain of about 30, while the crackle-okay method yielded over 50, sometimes 60. that's a lot of gain to give up. too much for me. there's other things about the method i use that i like as well, which have not been mentioned here. 8^)
Quote from: stmMan, the EDIT function is gone!
Edit to the above post: you can label the pushbutton "MUTE" :wink:
STM
it would be nice if someone made a pot that had a switch that pushed in momentarily, just for this function! i suppose i could isolate the pot using shoulder washers, put a metal knob on it, and use touch-detection to intitiate the mute function. i considered that as well. seems like it could make for a fun effect as well... leave a chord hanging, and raise the volume while muting it in time with the song (or off-time).
Zachary, isn't it possible to place a touch sensitive metal pad near the pot, so when your hand is close it detects its presence and automatically activates the mute option? Perhaps using the PROBE technology?
Another option would be an optical reflective array to detect the presence of the hand/fingers near the knob.
Regards,
STM
Why not just use the mute button that came with the SHO...the on/off stompswitch?
Quote from: Khas EvetsWhy not just use the mute button that came with the SHO...the on/off stompswitch?
:idea:
HAHAHAAHahaaa
LMFAO.
Sometimes its the simplest solution that is the hardest to arrive at. :lol:
Good idea.
Quote from: stmZachary, isn't it possible to place a touch sensitive metal pad near the pot, so when your hand is close it detects its presence and automatically activates the mute option? Perhaps using the PROBE technology?
Another option would be an optical reflective array to detect the presence of the hand/fingers near the knob.
Regards,
STM
sure, and i'll put a little tv monitor in it so you can watch the sports station at the same time!
8^P
Zachery wrote:
Quotesure, and i'll put a little tv monitor in it so you can watch the sports station at the same time!
:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: Give me a minute while my sides stop hurting... OK.
Hey, can I get the cartoon network instead?
stm, that's an interesting idea but won't that take up some serious real estate? Also, what would happen if your foot crossed over that section while you're playing?
AL
Quote from: ALwhat would happen if your foot crossed over that section while you're playing?
You could add a
separate switch to turn the mute function on or off. :D
This is what I had in mind:
http://tinypic.com/22gmx2
An 8-pin IC plus three discrete components do not eat too much real estate, moreover, considering you use SMT.
Datasheet here:
http://cache.national.com/ds/LM/LM2907.pdf
And by the way, the idea of a graphics LCD on stompboxes is not far from reality. Today the cellphone industry has them produced massively and are very cheap. A single IC is all that is required to turn one of these beauties into a realtime waveform or spectrum analyzer. I guess the first one to put this out will make some serious money, just for the mojo.
Zach, if I were you I would seriously consider filing a patent on this idea, unless someone else has already done it :shock:
Take care,
STM
i have this layout...
(http://www.massirsello.it/sho_layout.gif)
i've built it but the efx doesn't boost...the sound is a little compressed but without boost...
can u see something wrong?
thx
stm - now that's some thinkin'. Great little circuit - I can think of about a million things to do with that. Thanks for the info. Finger contact switch - I've seen those used in other areas. The panel would need to be separated from the box so you don't ground out - or would it? Would something like that introduce any noise into a circuit? :?
HrD - I realize you've only made a few posts. Zach has asked that his schems and/or layouts not be posted. You may want to take that down, or if you can't, at least contact an administrator and have them do it. If you need a clean boost purchase the SHO or check out Jack Orman's Boosters at AMZ.
AL
Quotecan u see something wrong?
Ah, some people will!
Quote from: zachary vexQuote from: stmZachary, isn't it possible to place a touch sensitive metal pad near the pot, so when your hand is close it detects its presence and automatically activates the mute option? Perhaps using the PROBE technology?
Another option would be an optical reflective array to detect the presence of the hand/fingers near the knob.
Regards,
STM
sure, and i'll put a little tv monitor in it so you can watch the sports station at the same time!
8^P
i vote for a scope, so you can watch your signal in action! :D
Spectrum analyzer would be in line here--then you could use the pedal to pink your amp--with some amps, you wouldn't want it pinked, but you could use it to EQ to whatever contour sounds good in your amp.
Quote from: HrDi have this layout...
i've built it but the efx doesn't boost...the sound is a little compressed but without boost...
can u see something wrong?
thx
hey, HrD, hi, umm... i don't mind if you look at naked pictures of my girlfriend in the privacy of your own home, but could you not lift up her skirt in public? it's not her a** you're showing there, but the idea is getting under my skin. capisce? okay, that's Italian-American slang... i should spell it Soprano's style. ca-peesh?
ok...zach..I try to solve otherwise... :cry:
i've done the fuzz fu*k troy...my personal re-interpretation...of your fuzz factory...it sounds great!
can i post...the digital paint???.....my enclosure...looks quite similar...!
(http://www.francescoaccardi.com/xxx/fft.gif)
thx for what u've done and for the efx that U R going to produce!
Quote from: HrDok...zach..I try to solve otherwise... :cry:
i've done the fuzz fu*k troy...my personal re-interpretation...of your fuzz factory...it sounds great!
can i post...the digital paint???.....my enclosure...looks quite similar...!
(http://www.francescoaccardi.com/xxx/fft.gif)
thx for what u've done and for the efx that U R going to produce!
12 posts and already you're a genius? thanks for being so kind.
the 10k was supposed to be a 10M. and the transistor was backwards. source always to ground with an n-channel mosfet (or any n-channel fet for that matter.)
and next time you see my girlfriend, a smile and a nod is in order, capeesh? 8^)
Quote from: ALstm - now that's some thinkin'. Great little circuit - I can think of about a million things to do with that. Thanks for the info. Finger contact switch - I've seen those used in other areas. The panel would need to be separated from the box so you don't ground out - or would it? Would something like that introduce any noise into a circuit? :?
Place a chromed or stainless steel bolt through a plastic insulating bushing, similar to the plastic pieces used for mounting TO-220 devices, but larger. Then attach a wire that may be kept in place by the nut, and connect to the input of the circuit.
This circuit shouldn't introduce any noise. The principle is the mains "hum" you introduce when touching the input plate. Similar to when you touch the tip of the guitar cable without touching the sleeve--the amp goes mad!. Of course a MOSFET at the output instead of a bipolar transistor would be great for audio usage. The output transistor should drive a JFET or MOSFET, depending on the polarity of the output (i.e. if the transistor is active with or without the finger touching the plate).
I always arrive late when key schems are disclosed. Not that I intend to copy it or take advantage of it, but I'm always eager to see how things are done for educational purposes. Good for Zach it was taken down rapidly.
Regards,
STM
Quote from: zachary vexQuote from: HrDok...zach..I try to solve otherwise... :cry:
i've done the fuzz fu*k troy...my personal re-interpretation...of your fuzz factory...it sounds great!
can i post...the digital paint???.....my enclosure...looks quite similar...!
(http://www.francescoaccardi.com/xxx/fft.gif)
thx for what u've done and for the efx that U R going to produce!
12 posts and already you're a genius? thanks for being so kind.
the 10k was supposed to be a 10M. and the transistor was backwards. source always to ground with an n-channel mosfet (or any n-channel fet for that matter.)
and next time you see my girlfriend, a smile and a nod is in order, capeesh? 8^)
Zac...
you are a gentleman and a scholar ! :)
Andy
...now about those nekkid pictures!
:twisted:
RDV
This is a simpler version of a touch sensitive switch (or mute device, depending how you wire it). Requires a Mosfet, a cap and a resistor only.
http://tinypic.com/view.html?pic=22kv2u
The principle of operation here is the conductance of your finger will let a small current flow which should produce several volts across R1, being enough to turn on the Mosfet. Increase the value of C1 if a softer action is desired. Don't use electrolytic or tantalum caps, since leakege would be too high.
This circuit is only sensitive to *finger touch* only, not proximity. Glove usage not recommended!
Now this takes minimum space and uses readily available components. Two bolts mounted isolated from the box may be used as contact plates.
Regards,
STM
thx Zack!
i'm gonna applie your suggest as soon..as i can...i want to play SHO with my les paul....and my telecaster.
now i'm gonna finish my Loved Stone - FIshball...another personale re-interpretation ...(LOvetone - meatball)
Hey ZaCh....IO CAPISCO...e Tu Capisci? :D
Quote from: stmThis is a simpler version of a touch sensitive switch (or mute device, depending how you wire it). Requires a Mosfet, a cap and a resistor only.
http://tinypic.com/view.html?pic=22kv2u
The principle of operation here is the conductance of your finger will let a small current flow which should produce several volts across R1, being enough to turn on the Mosfet. Increase the value of C1 if a softer action is desired. Don't use electrolytic or tantalum caps, since leakege would be too high.
This circuit is only sensitive to *finger touch* only, not proximity. Glove usage not recommended!
Now this takes minimum space and uses readily available components. Two bolts mounted isolated from the box may be used as contact plates.
Regards,
STM
Hi STM... I can't see the picture of the schematic...
Could you re-post it. I would use this kind of switch.
stm (Sebastian) has taken a longer "holiday" from the forum...
uuuups... Does anyone have the schematic???
:roll:
Quote from: spudulike:roll:
agreed
-sigh-
PnL,
Jeff
Moisho -
This usually gets mentioned in the thread, and my apologies if it has already been mentioned above (I know Zach himself posted to this topic), but to someone just coming across the forum, the question seems innocent enough yet you will get strange reactions.
As you'll find in other threads, Zach has requested that his schematics not be shared. Because he hangs out here, contibutes, and is "one of us," the wish is respected and posting of any Zvex schematics is against forum policy.
I personally have not tried a SHO pedal with my own setup, but I have heard good things about them. Most people say they are more than worth the price if you have a quality setup already - i.e., decent guitar into a decent tube amp.
If you wish to experiment with a booster, try something like the MOSFET booster, mini-booster, the EH LPB's, etc. What sort of sound are you going for? Perhaps you can start a thread and ask for suggestions based on what goal you're trying to achieve.
Hey guys... hopefully its not a bad thing for me to repost stm's touch-mute schem in this thread (i think thats what moisho was referring to, not the SHO), but i saved it locally... i dunno if he purposely pulled the schem as part of that holiday or if it just doesnt point to the right pic anymore.
I'll take it down if anyone objects. Not trying to stir up any trouble
(http://img.photobucket.com/albums/v515/Nabotics/Touchsensormutedevice.png)