Danelectro - CO-1 - Cool Cat Drive  [schematic]

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Ripdivot
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Post by Ripdivot »

IvIark wrote:I don't think it was spreading misinformation, I think some people should maybe chill out a bit. Pedalpusher was simply giving his initial thoughts and by the looks of the drawing by snyder80 it would appear that his hunch was fairly accurate.
I agree. Sometimes I think people get a little carried away here.

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Post by analogguru »

Torchy wrote:
Pedalpusher wrote:Analogguru said in another thread..."Save your time, when you want to do it like fuller did.....
That´s not mos-fet-clipping, that´s normal diode clipping even with mosfets
The inside-protection diodes are not mosfet-diodes, they are normal and will conduct long before the mosfets will conduct."
So fucking what ? AGs opinion is irrelevant to the thread you started. YOU have made a serious allegation of commercial copyright infringement ...
If the MarkM schematic is accurate then the CC Drive is based on the OCD and laid out the same way. FB loops, diode clipping, tone and volume, it's all the same. I haven't figured out all the values yet though.
Given that the OCD is a tweaked VLOD with mosfets as clippers (and that is a FACT, Fuller admitted as much), if you build it without mosfets its just a tweaked VLOD.
To clear the things a little bit up:
1.) I think we can agree, that there are different versions of the OCD.
2.) I am referring to MarkM´s schematic - I don´t know which version.
3.) I think we can agree, that there are 2N 7000 as so said "mosfet-clippers".
4.) If you look in the datasheet you will find the symbol below - I took this symbol twice and configured them as in the OCD corresponding to MarkM´s schematic. In this schematic are not drawn additional diodes.
Image
5.) if you look further in the datasheet you will find that the response curve of the protection-diode is a typical silicon diode with approximately 0,65V voltage drop.
6.) the typical Vgs-on of the FET is mentioned at 2,1 V
7.) so we have FET 1, Diode 1, Diode 2, FET 2
8.) now lets raise the voltage between the top and the bottom. That FET 1 would turn on there would be necessary a voltage of 2,1V - but this will never happen because Diode 2 is already conducting at 0,65V
9.) now lets have a look at the opposite direction. We need to raise the voltage to - 2,1 V that FET 2 would turn on, but this will never happen cause Diode 1 already is conducting at - 0,65V
10.) Therefore you can ommit the FET´s because the clipping/distortion only occurs in Diode1 and Diode 2
11.) so the OCD may be closer to the VLOD as assumed.
12.) A later version had at least one germanium diode in series, not 100% clear is, if the Ge-diode is in series with the protection diode or if this diode disables the internal prtection diode of the FET.

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Post by Pedalpusher »

Ok. I'm back. Sorry for going off on You all. I heard some very distressful news yesterday and was still reeling from it. Doug, I as I stated earlier in the thread I did post pics in the TO thread. In my raunchy mood I deleted them. I was going to post some more pics with better resolution when I can get another camera. The best I can say is that ignoring the values, what I saw of it could be matched to the MarkM schematic except for the diodes. I didn't note any of the values. Some of the caps don't have any markings that I can see. I'll be pretty busy for the next few days but if I get time I'll post more info and pics. Also My Brother has a V1 OCD and We're going to get together and A/B them. I'll post My thoughts on that too. Again, sorry for the outburst.

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Post by Pedalpusher »

Pedalpusher wrote:what I saw of it could be matched to the MarkM schematic except for the diodes.
Also the HP/LP switch is absent as is obvious.

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Post by DougH »

I as I stated earlier in the thread I did post pics in the TO thread.
Good deal, I didn't see that, sorry...

As for the protection-diode clipping thing- this is really really old news...

Aron did this with his Shaka 3 ten years ago, based on a suggestion by John Greene. He used it for shunt clipping and it sounds very good. I don't know why more boutiquers have not tried this. Then again, I do know- something to do with their collective imaginations fitting in a thimble or something... But anyway, this is hardly an "innovation" on Fuller's part. It's old old stuff...
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Post by analogguru »

As can be seen here (scroll down):
https://www.diystompboxes.com/pedals/schematics.html
the Fet in the shaka had a Ge-diode in series to disable the internal protection-diode.

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Post by DougH »

Hmm.... Looks like it is oriented the same way as the protection diode shown in your schematic above:

https://www.diystompboxes.com/pedals/shaka3.jpg
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Post by Fuzzer »

But, doesn't it disable both diodes? I mean, effects both diodes at the same time with its 0.3 [V].

The way I see it, the disabling diode should be Cathode connected to the Drain and Anode to the gate. Please correct me if I'm missing something.
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Post by DougH »

The protection diode is connected to D-S. Look at AG's diagram above, cathode is on the Drain. The 1n34a's used in the SB3 are oriented the same way- anode on gnd, cathode on source. So they are in the same direction as the protection diode and don't "disable" it. It is a case of two diodes in series.

Now John Greene's original idea was oriented the other way around to use the MOSFET for clipping. But Aron's SB3 actually used the protection diode in series with a Ge diode.
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Post by Fuzzer »

Thanks very much, I wrote the former post with the thought of using the VGS diode in my mind.

But when I referred to cathode (I'm sorry for not being sufficiently clear) I was referring to the cathode of the additional germanium diode. But that was actually stoopid, because for that purpose, you just conenct the Gate and Source.

Thanks again.
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Post by mfgobbi »

Pictures of the Cool Cat Drive...

Image
Image
Image
Image
Image

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Post by ShortScaleMike »

This is my favourite of the three Cool Cats I have (Drive, Transparent Drive, and Fuzz). It's a very cool pedal, does not remind me of the OCD really, it has way more top end. I could dime the Tone control on my OCDv3 when I had it and not have any piercing treble, whereas the CD-1 tone control sounds best to me between 9 o clock and 12 o clock.

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Post by mfgobbi »

Someone has done the job below and posted in TGP.

Image

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Post by TubeDude22 »

mfgobbi beat me to it.

The Cool Cat Overdrive is an OCD clone.

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Post by audiohub »

The schematic as shown has a few errors....the VR should connect to the R1-diode junction instead of the R3-R4 junction, and there is a 4.7K resistor connected from the Q1 emitter to ground. Everything else looks about right. A sort of cross between the VLOD and OCD. I modded mine to the current OCD V4 specs last night, and it sounds very good. Got it from eBay for $24 delivered to my door. Incredible.
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Post by ShortScaleMike »

I would disregard that schematic until someone with more experience RE-rs this pedal. The guy was a self confessed beginner. I'm interested as to why it was so much more trebly than the OCD I used to own? Op-Amp?

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Post by nooneknows »

audiohub wrote:I modded mine to the current OCD V4 specs last night, and it sounds very good
I'm interested in it, please, what did you exactly change?
thank you

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Post by audiohub »

I'm interested in it, please, what did you exactly change?
I changed C9 to 68nf, C3 to 1uf tant, C12 to 47nf, and replaced the clipping diodes with 2n7000's (plus diode on one). I also removed the output buffer by removing C11, C13, R13 and the 100k tied to the output, and jumpered the wiper of the output pot to the out jack connector. The whole process took about half an hour, and the connectors make it easy to remove the board to mod it.

IIRC, the 9V supply does not go in series through the diode as shown. The diode (1N4004) is connected from supply to ground for polarity protection, and a 100uf and (probably) 100nf cap are tied from supply to ground for filtering. I didn't remove any of the tiny SMD caps to measure them, but might this weekend. I'm guessing that with so much else of the circuit copied, these are probably correct values. A nice feature for the SMD electrolytic caps is that there are connected through holes underneath them when you remove the caps, making for easy replacement with through hole parts. Nice!

I didn't have a SMD TL082, so I left the stock TL072 installed for now. I've noticed a number of people here claim the the 082 is a key component of the OCD sound, so I'll order some soon to replace it and see for myself. I may also try replacing C8 at some point with a multilayer ceramic.
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Post by Greg »

ShortScaleMike wrote:I would disregard that schematic until someone with more experience RE-rs this pedal. The guy was a self confessed beginner. I'm interested as to why it was so much more trebly than the OCD I used to own? Op-Amp?
I have seen reports that the OCD sounds different when followed by a pedal with a buffer...
The Dano version has an output buffer that the Fulltone doesn't.
I suspect this is why.

I also think this drawing is enough confirmation of the origins of this pedal.
Whether the guy's a beginner or not, the similarities are much to close to be coincidence... essentially it's an OCD with an output buffer and silicon diodes instead of Mosfet diodes.
It sounds good and has the same ability to clean up that the OCD does.
I don't see the relationship to the VL Overdrive either. It uses the OCD gain pot positioning and the filter values are exactly the same as the OCD.
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Post by Greg »

I don't know why I'm surprised... but I am..

The guy from Rocketfire guitars who did the drawing of the Dano Drive is selling them modded on Ebay:
https://cgi.ebay.com/MODDED-Danelectro- ... dZViewItem

yet reading the thread on TGP.. he seems to have very little idea what he's doing.
:mrgreen:

Rocketfire quote: "But, It's 100% for CERTAIN resemblant of an Ibanez TS circuit. That's not even questionable. No speculation."
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