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Goran
Double Platinum Member
Sweden
2203 Posts |
 Posted - 06/28/2007 : 07:15:24
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Found this on the net, written by Analog Man:
"analogmike07-17-2006, 09:07 AM
The Boss OD-1 was about the first OVERDRIVE pedal made, except perhaps the Ibanez Overdrives. But the early Ibanez pre-tube screamer OVERDRIVES were quite fuzzy and distorted, while the OD-1 is the first of the "tube screamer type" overdrive pedals. It was in the very first series of the Boss Compact Effectors. The OD-1 came out in 1977 and was discontinued in 1985. They were very popular in the LA metal scene in the mid 80s and the Japanese scene in the same time and much longer. The SD-1 took over from the OD-1 in the mid 80s but people still wanted that pure OD-1 sound. The OD-1 (and SD-1) use asymmetrical clipping, which Boss has a patent on, to give some thick overdrive with an edge. Tube Screamers use symmetrical clipping for a smoother, warmer, less edgy sound.
http://www.analogman.com/graphics/od1.jpg
The original OD-1 was made with a QUAD OP AMP CHIP, seen at the left. This RC3403D chip has 14 pins.
http://www.analogman.com/graphics/od1oldchip.jpg
Some early ones (1978) used an NEC uPC4741C quad op amp instead. Later versions used a common dual op amp, with 8 pins. Usually a 4558 chip was used, and often the famous JRC4558D as seen on the right. But the sound of the later unit with the smaller chip was NOT the same as the original version. The oldest versions will have a metal thumbscrew and ink-stamped serial number in the battery compartment. But some with the small chip have those features, too (1980). So the only way to tell if you have the GOOD ONE is to look inside for the chip and see if it is the small one (8 legs) or the big one (14 legs = best tone).
http://www.analogman.com/graphics/jrc-tl.jpg
In the BOSS BOOK, they say that they stopped using the big chip (made by Raytheon in the USA) because they had some failures. They switched to a Japanese made IC instead. I think it may have had more to do with cost and using Japanese parts, but for whatever reason, the circuit changed and I think in a detrimental way.
In early 2005 I finally sat down with older and newer pedals as I agreed to modify one for a customer. I found the main difference was capacitors, several smaller value capacitors were used, sucking away low end and making a thin tone.
Substutiting the old capacitor values helped a lot, it sounded almost exactly like the old one! Then I tried to install the larger chip in the new board, it did not look too hard as there was room for it. But it was very difficult as four of the legs had to go to different points on the board, and some bias resistors had to be changed to use a chip instead of the transistors that were used on the newer versions. These two transistors have to be removed. I was successful installing the large chip, and it sounded a little better but almost the same as with just the capacitor mods.
Have fun!"
Interesting that it�s not entirely the 14-pin chip that makes the old ones better, just the capacitors. |
Edited by - Goran on 06/28/2007 07:17:05 |
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 06/28/2007 : 14:40:49
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Somebody on this forum ever tried and compared the 14-pin and the 8-pin OD-1?
I have tried my best friends� 14-pin a couple of times but not side by side to the 8-pin, so I can�t give any judgement.
I have several times tried to buy it from him, but no, it was the first pedal he ever bought�
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visserman
Platinum Member
1072 Posts |
Posted - 06/28/2007 : 14:43:32
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Yes I have them both and we have talked about this before, but heh, it does not matter really.
Is the later version very different compared to the first one?
A little but not that much. Yes first issue sounds good, it is "Marshall Plexi in a box sound". I know many overdrive pedals will get you there, but the OD-1 is really the closest to that sound.
Each and every time I get the OD-1 out it surprises me how good it sounds.
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Edited by - visserman on 06/28/2007 14:48:11 |
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guirat
Silver Member
United Kingdom
186 Posts |
Posted - 06/28/2007 : 17:42:14
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Thanks for the info, that probably makes mine a 1978 model as it's got that NEC chip. No serialnumber though, I can only guess it got cleaned off.
It sounds great, like tube amp overdrive - a detectable 'crunch' which I'd always wanted (I have no valve amp to get similar so I'm using my imagination here). Whether it's special in this regard I don't know, I haven't the experience with other pedals to say, but it'll be just fine for me.
I liked the HM-2 when at minimum settings, the OD-1 gives a lot more control in that sort of overdrive range without getting fizzy.
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Analog Man on OD-1
