Fulldrive 2 pcb or vero layout for Hammond 1590BB?

Started by vanessa, November 09, 2005, 01:18:33 PM

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vanessa

I saw a post during a search that someone had a pcb layout but now the link is dead. I wanted to build one of (newer comp cut version) these sideways in a 1590BB. Anyone still have that one or something that would work in that enclosure?

:icon_rolleyes:

TheBigMan

One of Torchy's Vero layouts is for the Tube Screamer, now hosted by wampcat.  From there it's a fairly simple conversion to an FD2.

no one ever

it doesn't specify what transistors/ic to use though.. ???
(chk chk chk)

vanessa

Quote from: TheBigMan on November 09, 2005, 05:37:01 PM
One of Torchy's Vero layouts is for the Tube Screamer, now hosted by wampcat.  From there it's a fairly simple conversion to an FD2.

I have all of those layouts and I can't say that I see one in the lot. The FD2 is a bit more than just a TS808 with a 1N4005 in the clipping stage. For one it had a gain boost section. I would also like the 'flat mids, vintage, comp cut' mods as well. I just thought that someone had a layout of it to save me some time. But thank you for the info.

TheBigMan



Okey dokey, lets see what we can do here.  Firstly, the TS-808/9 etc generally used 2SC1815 transistors in the i/o buffers.  Just about any low noise NPN will do though, cos it's just an emitter follower.  The FD2 schem indicates 2N5088 for the transistors.  For opamps, either the JRC4558D or RC4558P are the obvious choices: schem uses JRC4558D.

The gain boost mode is quite simple, you don't need to alter the layout at all as the other parts mount onto the switch.  Use this diagram to wire it up.  The layout also show assymetrical clipping as used by the FD2.



All the comp cut switch does is remove the clipping diodes, so the pedal acts as a rather dirty booster.  This is also one of the TS-9DX's modes.

And finally, how to wire the FM/comp cut/vintage switch is shown in this schematic, but the comp cut and vintage modes are labelled in reverse.



Seeing as most of the modifications are off board you could also use a PCB from www.generalguitargadgets.com

HTH,

Andy.

vanessa

Why thank you. I did not know it was that easy. I did have a question. MF talks about the 'flat mids' being "sought after by eBayer's". Looking at the top schematic it says it's from his early Hammond box #157 around 1996. These two schematics look the same except the addition of the "FM/CC/V" switch. Where is he getting that his old pedals had a flat mids tone to them? Is there another schematic we're not privy to?

SteveB

Quote from: vanessa on November 09, 2005, 09:04:43 PM
Why thank you. I did not know it was that easy. I did have a question. MF talks about the 'flat mids' being "sought after by eBayer's". Looking at the top schematic it says it's from his early Hammond box #157 around 1996. These two schematics look the same except the addition of the "FM/CC/V" switch. Where is he getting that his old pedals had a flat mids tone to them? Is there another schematic we're not privy to?

I think what he means is that the non-flat mid FD's are supposedly sought after.

Steve

mojotron

Quote from: vanessa on November 09, 2005, 09:04:43 PM
Why thank you. I did not know it was that easy. I did have a question. MF talks about the 'flat mids' being "sought after by eBayer's". Looking at the top schematic it says it's from his early Hammond box #157 around 1996. These two schematics look the same except the addition of the "FM/CC/V" switch. Where is he getting that his old pedals had a flat mids tone to them? Is there another schematic we're not privy to?

Nope, that last schematic is all you need - really. I'm guessing that his old pedals were the same without the switch.

For transistors it does not matter what you use - I used 2n5088s and 1n194/1n4001 in the clipping section - on the more recent fulldrives the tant caps are film caps. The selection of opamps is everything though.. IMO... but very subjective.

vanessa

#8
Looking at the two I would agree that he added that later maybe just as an add on. Maybe he is still selling a few NOS pedals on eBay on the side or he wants to dispel any myths that the older ones sounded better than the new ones by saying it can now be obtained by a switch. More likely the new change in tone is due to the lack of germanium transistor on the output stage. I wonder what the hfe was on that ge? It seems like a better choice to have it in the input stage at Q1?

TheBigMan

Quote from: vanessa on November 10, 2005, 01:35:06 AM
Looking at the two I would agree that he added that later maybe just as an add on. Maybe he is still selling a few NOS pedals on eBay on the side or he wants to dispel any myths that the older ones sounded better than the new ones by saying it can now be obtained by a switch. More likely the new change in tone is due to the lack of germanium transistor on the output stage. I wonder what the hfe was on that ge? It seems like a better choice to have it in the input stage at Q1?

I can't see that making much difference given that it's being used as a buffer rather than as a booster of any kind.  I must try that out though, I've got a few NPN CV7112s lying around.

vanessa

It might just sound a little different. Maybe some anal players really found a slight difference between the new one and the old one. Fulltone may have found it cost in-effective to continue to put ge's in there, but did realize that there was a slight difference in tone. Like I said he probably heard people saying the old ones were "way better" and saw a profit loss. By putting a switch on it to "switch in those tones of yesteryear" he could get rid of peoples buying fears and not have to waste good ge’s in the circuit.