"Superheated SHO" - asbestos gloves warning!
While messing with the basic SHO topology for another project another project (http://www.diystompboxes.com/smfforum/index.php?topic=83517.0) I decided to add a switchable SSRP section lifted from the BSIAB. The resulting output signal is what I can only describe as superheated. Best to don your trusty asbestos gloves before laying down some uber hot licks and riffs into a tube amp with this sucker...........
(http://i210.photobucket.com/albums/bb292/frequencycentral/SuperheatedSHO.jpg)
I actually prefer this version though, as it doesn't crackle. :icon_biggrin:
(http://i210.photobucket.com/albums/bb292/frequencycentral/SuperheatedSHO2.jpg)
Interesting- so it basically just switches between Mu Amp and err... regular? Interesting; I can't believe no one has thought of that yet. Does it sound "mini-booster-esque" while maintaining its "Mosfetty-goodness" in Mu Amp formation?
Yeah - I invented the mini-booster didn't I? Go me! :slap:
The superheated mode just gives more gain.
Quote from: frequencycentral on April 05, 2010, 11:03:51 AM
Yeah - I invented the mini-booster didn't I? Go me! :slap:
The superheated mode just gives more gain.
This will help me with learning how to do a layout.
Nice, Rick. Now the "SHO" is more like a Peppermill!
What changes in tone do you hear by changing the gate to drain capacitor?
Very Cool Idea. This adds some possibilities to the Twin Mu Amp format. :icon_cool:
I bet some bootiquer is already on it...
I love simple little projects like this. I put one together today on perfboard and good Lord is it loud! It's also noisy, but I'm guessing that it will be quieter once it's boxed.
Bravo!
QuoteFinished it this morning. I was at Radio Shacks door before they opened.
Ummm, I don'[t know a lot about DIY effects or guitar effects to boot, but I know that when I have my crappy little Crate practice amp at Vol 5, my SHO at Vol 5 and then I flip the switch for the 'Superheated SHO' . . . my pants get tight.
(http://i129.photobucket.com/albums/p218/stockmonkey42/DSC01216.jpg)
Freq', AWESOME addition to the SHO. Perfect.
(http://i210.photobucket.com/albums/bb292/frequencycentral/SHOHeater.gif)[/quote]
2 Brown Sounds in a Box...
It seems the 2N5457 are getting scarce!
I was reading this (http://circuitworkshop.com/forum/index.php?topic=460.0)
(http://i20.photobucket.com/albums/b230/zjokka/secretschemos/schem.jpg)
while noticed I have all parts at home so what best excuse for building one?
Then I found this topic and also have parts except the zener so... would a schematic like this work similarly?
(http://s2.postimage.org/4ulp9-8cba96e4f164ca50be42e0a12a8cccd2.png)
(differences: 1.5M res and 1N4148 instead of zener)
Also I was thinking of get the 5K pot (reverse log, isn't it?) as explained at geofex (http://www.geofex.com/article_folders/potsecrets/potscret.htm) even if I haven't managed yet how ;D otherwise I'd switch to #2 with res and cap.
Any advice?
You could use a red LED like the ROG Peppermill, or even a single 1n4148 between G and S should work. Lowering the 10M resistors to 1M will lower the input impedance. But yeah, the schematic will work.
Thank you, I'll try it, maybe looking for 10Meg resistors because looking at the Zvex presentation the 5Meg impedance is characteristic.
Thanks
P.S.: having trouble showing my schematic image... should by fixed now...
(http://s2.postimage.org/4ulp9.jpg) (http://www.postimage.org/image.php?v=Ts4ulp9)
Quote from: neurino on June 12, 2010, 10:25:58 AM
Thank you, I'll try it, maybe looking for 10Meg resistors because looking at the Zvex presentation the 5Meg impedance is characteristic.
5M input impedance for AC signals is only realized at 0.53Hz, where the reactance of the input capacitor equals 2M, and provided the gain is set to unity to provide the maximum input resistance of about 3M.
For signal frequencies the input impedance is never much more than 3M, and falls as the gain is turned up.
? the many faces of.... mu-amps ?
niiiiice!
Here's a layout for the now re-christened Red Dwarf Boost, the PCB is available from guitarpcb.com: http://www.guitarpcb.com/apps/webstore/products/show/1656920
This is the crackle-less version, with the addition of a 1M pulldown. There's a soundclip at guitarpcb.com too.
(http://i210.photobucket.com/albums/bb292/frequencycentral/RDBPCB3.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/RDBPnP3.gif)
I listened to the soundclip, it really gives a desperate amount of volume ;D
I already imagine the guy at the mixer aiming at you with an axe: "turn that down!!!"
I hate to resurrect an old thread, but can someone tell me what the superheated section does? and how many volts it puts out?
Hey Rick, your layout for the Red Dwarf Boost is missing....
There was an error in the earlier layout, here's a corrected layout:
(http://dl.dropbox.com/u/967492/RDB%203%20PCB.gif)
(http://dl.dropbox.com/u/967492/RDB%203%20PnP.gif)
Awesome, thanks Rick. This is making it's way up my list.
Gi want to build this now! can 5457 replace by j201 here?
I never have been as fond of Jfets as I am Mosfets. So guess which gain pig is going to put several of these on his bread board. Super Heated Obsidian or Box of Rock/Metal. ;)
After many, many hours of frustration, I have discovered that there is an error in the original schematic/s posted in this thread. I hunted around to find the original SHO schem and that was when I found it. In this schem, the zener runs between Source and Gate, where it should actually run between Gate and Drain (cathode to Drain).
After getting it working, it sounds amazing!!! Problem is, with the 'superheated' section engaged, I get a lot of compression on lower notes. Any suggestions for remedies to this? Lower input impedance?
Sorry, had a few drinks so this may be a blazingly obvious answer that I'm missing :icon_redface:
*edit* Should probably mention that I also substituted 2N7000 and MPF102 due to lack of availability of genuine parts. Shouldn't make a massive difference AFAIK, but just in case I'm missing something again...
Quote from: Cardboard Tube Samurai on July 16, 2011, 04:24:18 AM
After many, many hours of frustration, I have discovered that there is an error in the original schematic/s posted in this thread. I hunted around to find the original SHO schem and that was when I found it. In this schem, the zener runs between Source and Gate, where it should actually run between Gate and Drain (cathode to Drain).
How so?
Horse's mouth: http://www.zvex.com/module_instructions.pdf
BS170 datasheet: http://www.fairchildsemi.com/ds/BS/BS170.pdf
2n7000 datasheet: http://www.fairchildsemi.com/ds/2N/2N7000.pdf
The 2n7000 has the opposite pinout to the BS170 though........confusion may lie there.
As seen here:
(http://analogguru.an.ohost.de/193/schematics/Zvex_SHO.gif)
The zener in the original schems are substitutes for the combination of D1 and R3 in the schem shown here. These run between G and D in this schem, whereas the zener runs between S and G in your schem.
Woah, that pic is big!!! Sorry.
^^^ That
huge pic is of the SHO MkI, which was superceded by the SHO MkII as in my link here (of which you will note the URL):
Quote from: frequencycentral on July 16, 2011, 04:52:38 AM
Horse's mouth: http://www.zvex.com/module_instructions.pdf
Yep, just saying that if anyone is following the original schematic posted in this thread, they're going to run into trouble, that's all. I am aware that there are plenty of schems floating around the internet, but in case someone decides to make that one, just like I did, they will find that it doesn't work straight away. Young players may never get it to work.
Quote from: Cardboard Tube Samurai on July 16, 2011, 08:57:44 PM
Yep, just saying that if anyone is following the original schematic posted in this thread, they're going to run into trouble, that's all. I am aware that there are plenty of schems floating around the internet, but in case someone decides to make that one, just like I did, they will find that it doesn't work straight away. Young players may never get it to work.
I'm still mystified as to what the error is, as far as I'm concerned it's correct.
Quote from: frequencycentral on July 17, 2011, 06:56:17 AM
Quote from: Cardboard Tube Samurai on July 16, 2011, 08:57:44 PM
Yep, just saying that if anyone is following the original schematic posted in this thread, they're going to run into trouble, that's all. I am aware that there are plenty of schems floating around the internet, but in case someone decides to make that one, just like I did, they will find that it doesn't work straight away. Young players may never get it to work.
I'm still mystified as to what the error is, as far as I'm concerned it's correct.
"run between G and D in this schem, whereas the zener runs between S and G in your schem"
Quote from: Cardboard Tube Samurai on July 17, 2011, 08:11:55 AM
Quote from: frequencycentral on July 17, 2011, 06:56:17 AM
Quote from: Cardboard Tube Samurai on July 16, 2011, 08:57:44 PM
Yep, just saying that if anyone is following the original schematic posted in this thread, they're going to run into trouble, that's all. I am aware that there are plenty of schems floating around the internet, but in case someone decides to make that one, just like I did, they will find that it doesn't work straight away. Young players may never get it to work.
I'm still mystified as to what the error is, as far as I'm concerned it's correct.
.....whereas the zener runs between S and G in your schem
...and in the original Zvex schematic too. And ROG's Peppermill.
(http://i210.photobucket.com/albums/bb292/frequencycentral/SuperheatedSHO.jpg)
(http://dl.dropbox.com/u/967492/SHOO.JPG)
(http://dl.dropbox.com/u/967492/peppermill.png)
(http://dl.dropbox.com/u/967492/BS170.JPG)
(http://dl.dropbox.com/u/967492/2n7000.JPG)
Ok, we're not going to get anywhere with this. You're right. I'm right. Or so we both believe. All I know is, I followed your schematic and I couldn't get it to work. I've been doing this for a while now and whilst I'm certainly far from an expert, I understand the concept of different components having different pinouts, please don't insult me. I even went so far as to replace the 2N7000 at one stage, thinking that perhaps I might have stuffed it. I am more than willing to eat a massive chunk of humble pie if I am in fact wrong here but for the life of me, it still looks wrong, sorry. In fact, I'm going to go and study what I built just to triple check. Sorry, I'm not trying to be a sh!thead.
The thin insulating layer between channel and gate breaks down due to excessive voltage between gate and source. As far as I know that is always remedied by adding a zener between G and S, not G and D. Example:
"Direct protection of the MOSFET could involve methods such as shorting the gate
to the source, or applying zener protection gate-to-source."
From International Rectifier application note AN955 http://www.irf.com/technical-info/appnotes/an-955.pdf (http://www.irf.com/technical-info/appnotes/an-955.pdf) page 5.
Now I'm curious why yours didn't work.
???
Acceptable ESD-protection schemes include:
-Zener cathode to gate, anode to source
-Zener cathode to gate, anode to V- (ground) is also fine (provided: gate bias voltage < Vzener < 20 volts)
-Reverse biased, regular, non-zener diodes from gate to supply voltages is also fine, provided the supply voltage is kept lower than 19.3V
Zener from gate to drain is incorrect. I mean, it won't break anything to hook it up that way, but it will potentially mess with the bias and won't protect the gate from ESD.
I finally got around to building this up, and I'm getting absolutely no volume control from the bias knob. It's as if the knob was stuck at full on 10 the whole time. I've checked all wiring and the perf and everything seems kosher. The volume boost (non superheated) is incredible, bringing my 5w tube amp to an almost unusable volume when set at 1 (for stage volume, I normally need my amp set at 4 - this was more like a 7!) and hits my Echo Base so hard that it distorts. Superheated mode just about doubles the amount of volume boost!
Examination of the circuit brings a few questions to mind.
-Between version 1 (crackle ok) and 2 (no crackle), why the change in values for the drain resistor and source potentiometer?
-Why the inclusion of the 22K input resistor on your layout? It's not on the schematics.
I hope I can tame this beast down to usable levels, because from what little playing I got to do with it, the sound was fantastic.
Bump?
So, reducing the size of the potentiometer from 5k to 1k in the crackle-less version changes the gain of the BS170 from unity to something like +20db?
I'll try going to the 5k pot to tame the beast.
Still curious about why you made those changes Rick!
Built this SHO/Mu/Srpp on my breadboard and it rocks. :icon_cool:
Me too - built mine a couple of weeks ago. It's quite loud, which is a Very Good ThingTM. Now with my tame guitarist, along with an appropriate health warning. Not sure about "hot" and "superheated". More like "wild" and "completely insane". ;D
Two years old this very day!
Quote from: StereoKills on March 30, 2012, 03:09:38 PM
-Between version 1 (crackle ok) and 2 (no crackle), why the change in values for the drain resistor and source potentiometer?
I don't use 5.1k. The source pot was a 'Fuzzface lift'.
Quote from: StereoKills on March 30, 2012, 03:09:38 PM
-Why the inclusion of the 22K input resistor on your layout? It's not on the schematics.
guitarpcb.com sold that version for a while and wanted the 22k to reduce noise. ::)
Quote from: StereoKills on March 30, 2012, 03:09:38 PM
I hope I can tame this beast down to usable levels, because from what little playing I got to do with it, the sound was fantastic.
A few people have added an output volume control.
Quote from: StereoKills on April 04, 2012, 11:20:42 AM
So, reducing the size of the potentiometer from 5k to 1k in the crackle-less version changes the gain of the BS170 from unity to something like +20db?
I'll try going to the 5k pot to tame the beast.
Still curious about why you made those changes Rick!
Quote from: bluebunny on April 05, 2012, 08:18:38 AM
Not sure about "hot" and "superheated". More like "wild" and "completely insane". ;D
That was entirely my intention. :icon_mrgreen:
Quote from: frequencycentral on April 05, 2012, 08:40:29 AM
Two years old this very day!
Happy Birthday!
Quote from: frequencycentral on April 05, 2012, 08:40:29 AM
A few people have added an output volume control.
Why on earth...?? ;)
Quote from: bluebunny on April 05, 2012, 08:18:38 AM
Not sure about "hot" and "superheated". More like "wild" and "completely insane". ;D
Quote from: frequencycentral on April 05, 2012, 08:40:29 AM
That was entirely my intention. :icon_mrgreen:
Jolly good. Just checking... ;)
Just built this and it is not working (or I am wrong about how it shall work) - normal mode works fine, but when I turn to "Superheated" almost no sound gets out. Tried to switch 2N5457 to J201 and it works the same.
Am I missing something?
:o
I found out what was the problem - the switch was not working :)
However, I managed to add "superheat" potentiometer and I will post that schematic soon.
Here is the schematic with added "Superheat" pot, it controls distortion.
https://www.dropbox.com/s/qgsx9vn5vh6zwjm/Super%20Heated%20SHO.jpg?dl=0
Finally, Tynipic processed the image: (http://i64.tinypic.com/1z1ecdw.jpg)
Can't get this to load, sure would like to see it... Anybody?
Quote from: frequencycentral on July 30, 2010, 06:26:48 AM (http://www.diystompboxes.com/smfforum/index.php?topic=83692.msg720544#msg720544)<blockquote>Here's a layout for the now re-christened Red Dwarf Boost, the PCB is available from guitarpcb.com: http://www.guitarpcb.com/apps/webstore/products/show/1656920 (http://www.guitarpcb.com/apps/webstore/products/show/1656920)
This is the crackle-less version, with the addition of a 1M pulldown. There's a soundclip at guitarpcb.com too.
(http://i210.photobucket.com/albums/bb292/frequencycentral/RDBPCB3.gif)
(http://i210.photobucket.com/albums/bb292/frequencycentral/RDBPnP3.gif)
</blockquote>