School me on the Boss OD-1

RouseTheBoroughs

Silver Supporting Member
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2,653
I've seen a few of those go for a pretty penny lately, was offered one in a trade

What can you tell me TGP ?
 

scotticus

Member
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866
I'll try to help as I just did a lot of research before buying one. There are several circuit revisions, but from what I've read the biggest changes came when they switched from the early 14 pin chip to the common 8 pin 4558 chip. People still rave about the 4558 version, but the 14 pin chips are the most desireable/earliest/rarest. The 14 pin versions go between 300-400 and the 8 pin versions go between 150 and 250, give or take.
 

woolyh

Member
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1,020
I had a big chip version OD-1 and was really surprised how similar it sounded to the SD-1. They don't sound identical but it was so close I quickly sold it on, not worth the price unless your a collector IMHO.
 

MilwMark

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2,765
Edit - And they're all basically an SD-1 (Boss's most consistent drive pedal that goes all the way back to Japan) but without a tone control, right?
 
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Frosted Glass

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2,370
I had a big chip version OD-1 and was really surprised how similar it sounded to the SD-1. They don't sound identical but it was so close I quickly sold it on, not worth the price unless your a collector IMHO.
Boss made the OD-1 in 77, Ibanez/Maxon improved the design with a tone control (the tubescreamer in 78) which outsold the OD-1 so Boss copied the copy with the SD-1 (OD-1 with tone section) in 81, maintaining asymmetric clipping which they had a patent on. The OD-1 was then phased out of production.

The SD-1 is very similar to the final version OD-1 (OD-1E). I imagine the difference is like switching out the tone circuit which several ods and fuzzes allow you to do.
 

jsummersett

Member
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279
I have an OD1 that was a small chip version until I had Analog Man do the vintage mod which put in the big chip. I had an SD 1 before and while there are similarities in the sound there is no argument that the OD1 sounds better. I compare it to buying a leslie sim pedal vs playing through an actual leslie. I don't know what else they did to turn it into a tubescreamer but the OD1 sounds nothing like my 808HW or my TS10.
 

scotticus

Member
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866
Then whats the difference (I know there is a big one) between an OD-1 and an OD-3?
The following is copied and pasted from a member on tdpri named 11 gauge which sums the topic up pretty well…

"The OD-1 to SD-1 evolution wasn't really linear.

The OD-1 made its debut in November of '77. It went through a lot of revisions with different op amps and such. But by February of '81 the SD-1 was released as an improvement to the "final evolution" of the OD-1. Boss felt that a tone circuit was needed, so one was added.

...By extension of that, the SD-1 is primarily a final rev. OD-1 with the tone circuit. Boss had gone to the same 4558 chip as the TS with the final OD-1D's and all of the OD-1E's. Well, TS freaks will argue that it's different because Boss used the TL4558P, uP4558C, and C4558C along with the "real" JRC4558D.

IMO, most differences that people hear between the OD-1 and SD-1 are with the OD-1A to OD-1B series, which had the most circuit differences, and used the RC3404ADB and uPC4741C op amps. Boss had NO issues sourcing their parts from the lowest bid source, which meant NEC, TI, or whomever was cheaper than JRC! This is witnessed with the DS-1 to this day, as well as the numerous Boss pedals that use the "dreaded" L series op amps (8 pins in line).

The SD-1 has remained just about the same as it was in '81. The op amp now has two D's, but that just means dual layer, or quieter operation, slightly more gain as a result (negligible IMO, really). Even when Boss opened their factory in Taiwan, the SD-1 stayed the same.

The OD-3 has nothing in common with the OD-1. It is the offspring of the OD-2. The OD-2 was a radical departure in stompbox design, at least for Boss. It has NO op amps at all. It uses a configuration of transistors to simulate a crude op amp - the result is more favorable for use in stompboxes since it can't stay linear like a true op amp can - you get more inherent asymmetrical clipping! The downside is that it requires funky biasing and the circuit is complex in comparison to an 8 pin chip. In the case of the OD-2, the "turbo" mode cut the voltage down to UNDER 6VDC, which is why it distorts so readily. The array of transistors requires a pair of jFET's with a PNP bipolar transistor on the output.

...The normal mode with the OD-2 is basically a single gain stage with those three transistors, and the same clipping diode arrangement as the SD-1 in the negative feedback loop of the array. It runs at around 8VDC IIRC. The turbo mode uses a PAIR of those gain stages at lower supply voltage with NO clipping diodes. Both "meet" at the same tone circuit, which is identical to the BD-2.

The BD-2 is the ancestor to the OD-2. It basically takes the turbo mode and does the following things:

- voltage goes up to 8VDC
- first gain stage is set up like a SD-1, cutting all the bass out
- "fixed tone stack" that simulates BF/SF amp comes after first gain stage
- 4 clipping diodes to ground follow the fixed tone circuit
- second gain stage is like first, but doesn't cut bass like the SD-1
- a dual ganged 250K pot controls BOTH gain stages (one was fixed in the OD-2's turbo mode)
- there is a mild filter to remove some bass AND treble after the 2nd gain stage
- same tone stack as OD-2 is next in circuit
- an op amp boost stage comes AFTER the level control, and has a fixed ACTIVE bass boost

The OD-3 is the final offspring (thus far) and differs from the BD-2 in the following ways:

- true 9VDC operation
- first gain stage is unity gain with a fixed "notch" filter (cut before boost)
- second gain stage is like the ones in OD-2/BD-2, but it has clipping diodes before and after it
- third gain stage is a "discrete class A" stage with clipping diodes
- fourth and fifth stages are op amp ACTIVE EQ shaping - they are like a hardwired Baxandall tone circuit (bass and treble)
- tone circuit like in OD-2/BD-2 comes next, but has modified component values (for better bass/treble balance)
- level control is last, with no post boost op amp like BD-2

...The OD-3 gives asymmetric clipping with the most headroom, and the best staging of EQ filtering. There is no funky tone circuitry, all gain stages that clip have diodes to clamp them nicely, and the op amp portion is "encapsulated" within the circuit."
 

Pedal Dan

The Island of Misfit Pedals
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11,779
The 14 pin quad op amp OD-1 uses the other side for the in/out buffer... They replaced it with discreet components on the 4558's. Big deal.
 

tremolo3

Member
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4,781
After 4 paragraphs of scoticcus' post I started to think "hmmm 11 gauge?"

I love that guy in tdpri, so much wisdom.
 

OilsFan

Silver Supporting Member
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2,930
I've had the SD-1, OD-1 with 4558 chip and now the OD-1 with 14pin NEC chip. All good pedals I think but I prefer the 14pin NEC one. It can do some nice chord work capturing all the over tones well, with lead lines you can get some nice almost fuzzy tones and playing double stops really brings the 'blood' out if you know what I mean. It's the pedal that has the most heart to me.

I'll paste this clip below recorded with the 14pin OD-1. (Hopefully the style won't put you off LOL) The distorted chords are a Telecaster and an Epi DOT through the OD-1 panned hard right and left. The leads are a Tele on neck position through OD-1, CE-2, Carbon Copy and some VB-2 here and there. The Chorus hits are the DOT through OD-1, CE-2, Carbon Copy, VB-2 and DD-5 for hard repeats. The feedback towards the end is the DOT through the OD-1, CS-2, CE-2 and VB-2. All played through a Roland DEP-5 reverb into the front of a loud and clean Super Reverb.

[SOUNDCLOUD]https://soundcloud.com/trickedoutspaceshuttle/the-super-blue-moon[/SOUNDCLOUD]
 

jdel77

Member
Messages
10,072
I had a later 8 pin OD-1. That thing was so mid range pushed it make a Klon sound like a scooped Mesa-Boogie. Midrange City.
I sold it and much prefer a nicely modded SD-1.
That being said, I know of a silver screw OD-1 going cheap. I may grab it to try the Raytheon chip version out.
 




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