TS808 build with Fulldrive1 and or 2 options.

[Mark Abbott]

Dear Guys

I have an old RG Keen Screamtendo 64 pcb and I'm wanting to build up a versatile pedal. So far I have started with the 64 board in stock 808 setting and I ran it into a clean valve amp. My first thoughts were, this is crap, what is the big deal anyway?

I cranked up the amp (Champ style amp with 10" speaker) and the screamer sounded quite different, and I could see what the fuss was about. I have tried all of the switch settings and I really only like using four of the six switches. Two of which in effect give the pedal more gain, and maintain the bass response of the original pedal. I would like to be able to switch between a Keeley/Fulltone screamer and the stock one. The boost switch/pot combination seems like a good idea though I haven't experimented with it. I have tried lifting the diodes for the clean boost effect and that is okay too. There is however a big difference in volume between diodes and no diodes.

One of the switches puts another 0.22uf cap in series with existing one hanging off pin 1 of the first op-amp. This cuts the bass response and give the effect a bit more"clarity" this could be just the thing for someone with humbucking pickups in their guitar.

I have seen a couple of circuit diagrams with the Screamer/Fulldrive mod stuff, though I'm not sure how accurate they are.

If anyone has info on the comp cut/vintage switch and the flat mids thing I would like to see them to experiment with the circuit.

In closing I will say that the stock circuit does work very well though I'd like to try a few different variations out.

Thanks for your help.

Yours Sincerely

Mark Abbott

[MartyMart]

Read what Jaqcues say's about the "Ibanez TS808" here : www.ts808.com
It has a "Pro" label on it as in " TS 808 Pro " and really only works well together
with a big and LOUD valve amp.
I think that with a lot of stompboxes, "bedroom" level/use just doesn't do justice to 'em !!

MM.

[mojotron]

If you search on "fooldrive" there is a ton of info on this stuff...

[Mark Abbott]

Dear Guys

Thanks for the replies. Firstly, I don't think bedroom volume had much to do with the tone of the 808. I don't think it sounds good on it's own as a distortion device. I think it sounds cool when it is overdriving the first valve.

I did try a search on "fooldrive" and I came up short, dead links etc. Thanks agin for your assistance.

Yours Sincerely

Mark Abbott

[MartyMart]

Mark, PM me an email address and I'll send you the schem etc for the fooldrive.

MM.

[Barcode80]

i have to disagree about the ts808. running one into my simple solid state marshall 30dfx sounds killer at 2!

[vanessa]

Aside from the gain switch (which is essentially a gain limiter that passively cuts the gain control) the main tone difference between an 808 and the Fulldrive 2 is the use of one 1N914 and one 1N400X back to back in the feedback loop. This is the same type mod found in Analogman's "fat" section of the TS9/808 mod modes. Basically asymmetrical clipping as opposed to the stock symmetrical clipping in the 808. It really does sound nice and fat. I prefer this over the stock clipper. Put a switch in and you can have the best of both worlds. 

[vanessa]

If anyone has info on the comp cut/vintage switch and the flat mids thing I would like to see them to experiment with the circuit.

The original circuit has a germanium transistor at the output. I think this made the name for that pedal (and for Mike Full*r for that matter). Later the ge transistor was dropped for whatever reason and subbed for a si version. The "vintage" switch was added later for whatever reason as well (some say due to complaints that the newer si FD did not sound as good as the old one), (marketing I suppose). This switch does not switch in a ge transistor so if you're looking for the original FD tone you're not going to find it with that mod.

[Mark Abbott]

Thanks for all the replies, I appreciate all your help.

As far as what I think good tone is, well my opinion is the 808 sounds crap through my 5 watt Champ style amp, which will be different to someone else's opinion, and after all what is the point of arguing about it all, it's all about whatever works for you.

As far as the comp cut/vintage switch goes, I have no idea what it does, I'm simply enquiring, so I may experiment and evaluate the circuit to see if I think it is a good mod to implement. Like wise I'm wishing to find out more about the flat mids mod, though I'm a little sceptical about this one as I think part of the joy of the tube screamer series of pedals was that they introduced more mids into vintage style Strats which lacked midrange (but had marvelous chimey tone , yes I like chimey tone!)

I wouldn't know the difference in tone between an early Fulldrive, a Fulldrive 1, or a Fulldrive 2, and frankly I think I'd have to hear the difference before I were to excited about it.

Thanks for the tip about the 914 diode and the 1N400X series diodes, I used only 1N4007 diodes as I had them at hand. I was also thinking of trying the parallelled chip idea, though I would probably do that sort of thing at the end of the project, along with trying it out using 18 volts over the standard 9 volts.

Again thank you and I hope I've explained myself a little better.

Yours Sincerely

Mark Abbott

[mojotron]

As far as the comp cut/vintage switch goes, I have no idea what it does, I'm simply enquiring, so I may experiment and evaluate the circuit to see if I think it is a good mod to implement. Like wise I'm wishing to find out more about the flat mids mod, though I'm a little sceptical about this one as I think part of the joy of the tube screamer series of pedals was that they introduced more mids into vintage style Strats which lacked midrange (but had marvelous chimey tone , yes I like chimey tone!

Mark, before you experiment - this link, http://www.geofex.com/Article_Folders/TStech/tsxtech.htm to RG's "The Technology of the Tube Screamer" is a must read for any type of 'diode-clipper' circuit like this.... If there is one single document to check out to find out how circuits work, and how to analyze circuits - that link is it - and a great place to start.

[Dai H.]

couple of links--hopefully useful (some things can be hard to find because of the different terms used, etc.) :

http://www.generalguitargadgets.com/diagrams/ts_fulldive_1_sc.gif

http://www.generalguitargadgets.com/diagrams/ts_fulldive_2_sc.gif

http://www.kilback.net/homebrewtweaks/pedals/pedals.htm#fd2mod

FWIW, I have a TS-9DX I've modded with old parts (the older shiny "JRC4558D" chip, older caps as close as I could find, 2SC1815s from around the same period (80s)--basically as close as I could get without paying 800 bucks or whatever for an original TS-808, and it was pretty good into an acquaintance's old Marshall Supertrem, but I don't know about magical. I wouldn't call it bad though.

[SteveB]

The actual flat mid thing is another feedback loop connected from pin 7 of the chip to the drive pots. It goes through a 47k resistor, .010uf cap & a 10uf polarized cap. I tried it on one of my screamers & "thought" it made a difference, but after a while, I wasn't sure. It still never sounded exactly like my FD, but I was using a 500k drive pot & the FD uses a 250k for drive & 1meg for boost. I don't know....I just got tired of trying to get the flat mids, especially because I had a FD that did it well.

The mids it flattens seems to be in the lower mid register, somewhat removing a bit of thickness, making things a bit more "open" sounding to my ears. I have seen "mid hump" mods on other sites done by changing cap values only, but that is not the same as the feedback loop in FD pedals. As far as the one on GGG, it doesn't show the flat mids part in the circuit.

Steve

[Torchy]

[SteveB]

I was wrong. The FD drive pot IS a 500k. I was thinking of John Greene's design.

Thanks for the schematic Torchy.

[Mark Abbott]

Thanks for the circuit Torchy. Mostly I can see what it says, but it is a little blurred.

Thanks again for your help.

Yours Sincerely

Mark Abbott

[Torchy]

Full size schematic mailed

[Mark Abbott]

As we say in Australia Torchy, you're a little ripper!!!

Mind you a few Australians would feel a little embarrassed to use this term in George street Sydney, but that's their problem. 

Yours Sincerely

Mark Abbott