# Ibanez 850 Fuzz mini VS OD850



## jimmythegeek (Apr 17, 2012)

The description of the 850 fuzz says that it's based on the OD850. Does anyone here know the differences in the circuits? The idea of a tweaked violet Ram's Head Muff in a tiny enclosure sounds great but I'm wondering if the mini reissue fits the bill. The Maxon D&S would work too bit there's something about a tiny enclosure that appeals to my need to cram as much as possible onto a board.


----------



## mhammer (Nov 30, 2007)

The 850, whether earlier Maxon version or newer mini version, are one of MANY Big Muff topology fuzzes out there. That includes not only all the little tweaks over the years between issues of the actual BMP, but also clones from Boss, Ibanez, and a host of "boutique" makers.

The circuit is quite maleable with a component-value change here and there changing what people perceive as the character of the tone. Just how much those minor value-differences actually account for what people attribute to this or that pedal is a matter for empirical study. I read an interview with EHX founder Mike Matthews in a business magazine around 15-18 years ago in which he stated that, during the 70s, one could take any 4 consecutive BMPs coming off the assembly line, and they would all sound different from each other. Of course, we have no idea of *how* different or *whose* judgment that was, but given the wide tolerances of the capacitors used (look for pics and they will always look different from gutshot to gutshot), and the fact that 1% resistors were never used, unit-to-unit variation was to be expected. 

Having said that, large manufacturers use components with more consistent values these days, and production techniques have also become more consistent. Mini pedals like the Ibanez ones of interest are more than likely to use surface-mount components - a far cry from the "spider's web" flying leads that EHX would often use in the early days. The downside is that what would theoretically be a VERY simple mod to change this or that component value and shape the tone in the desirable direction, using thru-hole components, is a near impossible task now. So one has to *like* the commercially-produced pedal, given that you can't season-to-taste.

But, to get to your point, posted schematics of the Maxon 850 show it as very clearly a tweaked BMP. This short write-up notes the differences with the BMP: Ibanez OD-850/Maxon D&S OD-801


----------



## jimmythegeek (Apr 17, 2012)

I have heard that quote from Mike Matthews as well. Really, I think of any Muff clone fron that era as a clone of a single pedal rather than an overall clone. I really enjoy the Maxon 801/Ibanez 850 tone. Based on your response, I'm assuming the "based on" part of the marketing jargon simply means "we swapped some parts due to availability/consistency/ability to surface mount them in a tiny enclosure" rathet than an intentional attempt to alter the circuit for tonal reasons. 

I would love to read an empirical study of Muff variants and TS style pedals too. I have suffered from a serious TS hate for years with the exception of 2. One was a TS9 with all of the Monte Allums mods and the other was a TS mini. I can't explain why I like them more. My perception was that the tone knob had a more useable sweep (couldn't get an unpleasant sound out of the mini) but I have trouble believing that there would be that much inconsistency in one component from a major manufacturer working on a circuit that (despite the protestations of cork sniffers everywhere) hasn't really changed since the 70s. Maybe when they ended their arrangement with Maxon something changed?


----------



## mhammer (Nov 30, 2007)

Years ago, I built myself a Tube Screamer to 808 specs. Hated it, hated it, hated it. Simply could not see what the fuss was about. But my main (and maybe even only) guitar at the time had a pre-amp built in, so the output was pretty hot. That was NOT what the TS - *any* TS - wanted. Then I bought a new SC-equipped guitar that had no pre-amp and the pickup had a modest output. All of a sudden the skies opened. What the pedal wanted was a lower input signal, such that it could "ride" the clipping threshold. Naturally, with less overall clipping, the Tone control had a more pleasing impact.

It's worth noting that diodes of the same type can have a range of values. So a standard 1N914/4148 might have a forward voltage of 520mv or anything as high as 670mv. Now, that's certainly not as nuts or variable as the hfe of a germanium transistor, but it's wide enough to make an audible difference. Do major manufacturers "select" for things like that? I doubt it. I suppose they might go so far as to measure the Vf of a few from a batch, and then assume the rest of the batch have the same specs. But I seriously doubt anyone is sitting there with a meter, tossing diodes into the 520-540mv, 541-560mv, and 561-580mv bins.

Of course the impact of such diode-to-diode differences can be easily compensated for by other parts of the circuit, but nobody is going to those lengths, unless one is paying some ungodly amount for a boutique pedal whose price factors in all that labour.

As for what "based on" means, it can be a stupidly tiny change. For instance, if I used a 2.2M bleed resistor on the input to minimize switch-popping, and the original used a 1meg resistor, I can't say it is an *exact* replica. Similarly, if a vintage pedal used an electrolytic capacitor value on its output (e.g., 2.7uf) that you_ used to be_ able to get, but can't anymore (things tend to go from 2.2uf directly to 3.3uf these days), I can't say it was an "exact" replica. The change in component value may shift the low-end rolloff from 27hz to 16hz, neither of which would be audible by most people or reproducible by most guitar speakers. But people use the phrase "based on" to essentially cover their hindquarters in the event that someone gets picky.

The basic BMP design is a "double clipper". That is, it boosts the signal, clips the daylights out of it, then boosts and clips again. The double clipping is responsible for the sustain and loss of dynamics. Variations between issues of BMP (and clones "based on" it) take 3 basic forms:
1) variations in the tone cap values, where any scoop is located and how wide or pronounced it is;
2) how the gain is set in the clipping stages - usually reflected in making the collector resistance (between V+ and transistor), and/or the emitter resistance (from the transistor "arrow") to ground larger or smaller; and
3) varying the passband in the clipping stages - usually the value of the capacitor in series with the diodes, and/or the value of the "feedback" capacitor between base and collector.

The issue-to-issue, and product-to-product differences in transistor choices probably make less difference. I know people make a big deal of this or that transistor, but transistors are a _tabula rasa_: you can always get them to behave like each other with changes to components around them.


----------



## connorp (Jan 3, 2022)

jimmythegeek said:


> The description of the 850 fuzz says that it's based on the OD850. Does anyone here know the differences in the circuits? The idea of a tweaked violet Ram's Head Muff in a tiny enclosure sounds great but I'm wondering if the mini reissue fits the bill. The Maxon D&S would work too bit there's something about a tiny enclosure that appeals to my need to cram as much as possible onto a board.


I emailed ibanez, the circuit is exactly the same. incredible fuzz pedal. Best I've ever played honestly, I own 2 of them. The regular size and the mini. No audible difference.


----------

