Mat Mathias design intentions, when building OR100/OR120

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skylark
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Mat Mathias design intentions, when building OR100/OR120

Post by skylark » Thu Sep 22, 2016 7:24 am

Hi folks,

so i recently got an Orange OR120 that i run in OR80 mode. It is becoming more and more my favorite amp.

Hence i was wondering, if you guys know of a good article on the design intentions by Mat Mathews when working on the first Orange by Matamp models - the OR100 and later the OR120? I've read similar and very good/informative articles on VOX, Marshall/Fender, but have not found a similar article on the OR models.

I am interested about this, because as a user i find many great things about the OR120 - 1. the first vintage guitar amp that i know of, where the controls actually work and are very logical/intuitive, extremely versatile due to this - can be really bright or dark, 2. it has the full spectrum of distorion available - from slight overdrive, to flat out drive and even fuzz, while it can be tweaked easily to sound like an amp fed with an overdrive pedal, but WITHOUT the pedal (due to point Nr. 1), 3. the distortion character is very versatile, but in its basis it is full, very organic and rather smooth, no crazy frequency spikes, no britleness, twitchyness, etc., 4. full AND defined, but not harsh cleans, with a nice defined, but smooth top-end, 5. incredibly dynamic, retains clarity - easy to go from mean to clean, 6. takes pedals extremely well (had issues with some pedals on the Hi input, until i realized that Lo input takes everything perfectly - on par with the JTM 45/100 for the most part and even muc hbetter in some cases (Rangemaster treble boost for example).

The other amps i own or have played get some of these aspects right and all sound great in their own right, but this starts to look more and more like a dream-amp (for me at least).

As it ticks so many boxes, i am really intrigued about the history of the design process of these amps and if Mat Mathews has ever elaborated on what goals he went for with this design? Or maybe a tech savvy guy has written a good article somehwere with some good speculation on what the main design goals seem to have been and how they were achieved? How much of the Matamp 2000 is in the OR100 DNA, etc.? I have found some schematics and have started to compare the Matamp 2000 with the OR120 but i am not advanced enough in this to, for example, understand if the Matamp 2000 also had the baxandall tone stack (i see many similar elements in bith designs, but different topology). I would be interested in a lower power OR80 style amp with baxandall and it looks like the Matamp 2000 MIGHT be it.

Sorry for the long post and thanks in advance for any input and hints!
Last edited by skylark on Thu Sep 22, 2016 10:06 am, edited 1 time in total.

Randy Bass
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Re: Mat Mathews design intentions, when building OR100/OR120

Post by Randy Bass » Thu Sep 22, 2016 9:52 am

While his accordion solos were really terrific, I am not aware of Mat Mathews being involved in the design or production of Orange Amplifiers.

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Maybe this recent thread would be useful:

http://forum.orangeamps.com/viewtopic.php?f=2&t=54975
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skylark
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Re: Mat Mathias design intentions, when building OR100/OR120

Post by skylark » Thu Sep 22, 2016 10:09 am

:D a good one.

Shame on me... Mat Mathias, of course - this just confirms my noobiness to Orange and Matamp. Corrected the title.

Thanks for the link! I read that article yesterday and this is where the Matamp 2000 was mentioned. So i am now wondering how much of the initial design went into the OR100/OR120 and if anything is available, where the man himself speaks about his designs. I guess that not being in spotlight in contrast to the Marshalls, Voxes and Fenders, the Matamp history is probably not that readily available.

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Re: Mat Mathias design intentions, when building OR100/OR120

Post by Gladmarr » Fri Sep 23, 2016 2:53 am

I have read that it was designed to be as many things in one box as possible. Mat was going for a guitar/bass/keyboard amp. Swap the preamp and it was a PA head as well.

I believe the Matamp Series 2000 was the influence for the Orange/Matamp ORST. The ORST with more power became the OR100. The OR100 seemed to be the seed for the Matamp GT-120. And the OR120 is basically a stripped down GT-120. By that point Orange and Matamp were separate entities and Orange did a little tweaking of the design to make the OD120 and later the weird Series II amps.

skylark
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Re: Mat Mathias design intentions, when building OR100/OR120

Post by skylark » Fri Sep 23, 2016 7:11 am

Thanks for the input Gladmarr! will look into the ORST and successor amps a bit more, as they will be probably covered much better than the super rare 2000.

I guess you probably know this already, but here is a great article on the VOX amp design: http://www.stevesamps.co.uk/?page_id=287" onclick="window.open(this.href);return false;
And here on Marshall design from the same guy: http://www.stevesamps.co.uk/?page_id=289" onclick="window.open(this.href);return false;

I love Steve's articles. Something along these lines for a Matamp 2000 would be fantastic.

I am just wondering how much of the Matamp 2000 character is in the OR120 and vice versa. They seem to be VERY far apart in some respect - cathode bias vs fixed bias and the HUGE transformers in the OR80/120 vs the underpowered RS Deluxe OT, but in the schematic i see many similar elements floating around in the 2000 that i see in the OR120 schematic. From what i understand the 2000 already had the baxandall tone stack. I am wondering if the 2000 might have similar traits as a fantastic overdrive machine, with quite a bit of gin on tap, less headroom, lots of compression - like a smaller and softer OR120, or if it sounds completely different. I might end up building a 2000, as i was simply astonished by the inspiring craftmanship in these amps. Also the reissues are so rare that i do not dream to find one. As for lead dress - I thought Hiwatt set the bar in this area, but looks like Mats work was second to none and way before Hiwatt.

skylark
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Re: Mat Mathias design intentions, when building OR100/OR120

Post by skylark » Mon Oct 03, 2016 7:47 pm

Ok, so after reading some more bits and paying a bit more attention, i found that the Series 2000 seems to be based on a Hi-Fi amp design, the Connoisseur HQ20 by Tony Emerson. No idea how much of the design was based on the Hi-Fi amp, but it sure explains some aspects of Matamp and early Orange amps.

First thing that comes in mind are the monstrous transformers. After looking into it, i have not seen any amp manufacturer from the era up to the 70's with larger transformers than Orange - by guitar amp standards, they were overengineered. The transformers of the early units with Partridge iron are even bigger than what i see in Hiwatts.

So, yes, compared to almost any other guitar amp design that comes to mind, Orange has a huge frequency range, beginning from such deep lows as none of the otehrs can reach and going to a very detailed, but smooth, not harsh top end. Additionall, due to the baxandall, it is easy to get going from a flat EQ as a starting point. While on a Marshall it takes some practice and time, until you realize that treble = 0, mids = 10, bass = ~1 yields a more or less flat response :roll:

Gladmarr
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Re: Mat Mathias design intentions, when building OR100/OR120

Post by Gladmarr » Mon Oct 03, 2016 8:25 pm

I would love to see some of the source material you found for this study. Please put in some links!! 8)

jontheid
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Re: Mat Mathias design intentions, when building OR100/OR120

Post by jontheid » Mon Oct 03, 2016 9:54 pm

It is from the Orange website!

https://orangeamps.com/heritage/legacy- ... ge-matamp/" onclick="window.open(this.href);return false;

skylark
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Re: Mat Mathias design intentions, when building OR100/OR120

Post by skylark » Tue Oct 04, 2016 3:37 am

Yes, alao there are snippets from the book of orange on premierguitar.com, where the same is stated about the hi-fi amp.

And as for the series 2000, it used the Radiospares deluxe OT, which, as we all know, was a hi-fi OT and has a rather even response at the low 20w power rating of the amp. Once the power went up, so were the OT's being upgraded by the sam hi-fi standards rather than guitar amp standards.

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Re: Mat Mathias design intentions, when building OR100/OR120

Post by fiveightandten » Sun Oct 09, 2016 2:02 pm

You may be interested in this:
http://www.ebay.co.uk/itm/MATAMP-at-60- ... b8f&_uhb=1" onclick="window.open(this.href);return false;

Here it is on Amazon:
https://www.amazon.com/Audio-Engineerin ... 1901214575" onclick="window.open(this.href);return false;

I wrote some articles years back on the OR-80/OR-120 circuit design. It was on a Geocities page that has since been taken down. I may have the text saved somewhere if you're interested.

My interpretation (and this is just just an interpretation) is that they were designed to be as adjustable as possible, and to carry enough low frequencies for other instruments (keyboard and bass maybe?). The transformers are decent sized in the OR-80 and 120, but I never found them to be overbuilt compared to similarly powered amps. Some of the old OrMat amps have huge Partridge transformers that are much larger. I'd say that Hiwatts and Ampegs of the era had more overbuilt transformers and power supplys.

The FAC knob is an adjustable high pass filter. A bunch of caps in series that change the cutoff frequency of the filter as you turn the knob. It's sort of an adjustable coupling cap circuit, which allows you to tailor the low end response of the amp. A consequence to this is that the gain structure is altered.

I'm not familiar with Matamps, but in my GRO100 the FAC knob is the very first thing in the pre-amp. It's in line even before the first triode gain stage. The inputs feed directly into the FAC knob. This is quite different than the OR-120/80 which have the FAC late in the pre-amp.

While I do find old Oranges to have a lot of low end on tap, I never found them to have a lot of top end. Put an old Orange next to a Hiwatt or an Ampeg and you'll hear just how dark the Orange voicing is. There are a number of circuit elements that are there specifically to darken the amp up. There is a bypass cap on the plate of the last stage which does nothing more than filter out high frequencies. Without that cap, most old Oranges will oscillate at high volumes when the treble knob is up high (HF drive affects that as well). Somewhat due to layout (and maybe due to circuit design somewhat, as well) Oranges just can't pass the high end that some other amps can. You don't really need those frequencies for guitar.

Older amps (GRO100 circuits for sure, maybe others) also had a bypass cap on the negative feedback loop injection. Again, its only purpose is to remove top end.

The Baxandall tone stack is unique for a guitar amp. Ampeg V-series amps also used a Baxandall tone circuit. It's a very powerful tone circuit and capable of a wide envelope of frequency response ranges. Marshalls, in comparison, do nearly nothing! You can download the Duncan amps tone stack calculator from http://www.duncanamps.com" onclick="window.open(this.href);return false; and see the Baxandall TS at work against FMV type tone stacks. The functional differences are big.

The phase inverter and output section are also fairly unique for a guitar amp. There's a LOT of asymmetrical clipping in the signal when it's pushed into distorting. Long tail driver circuits are a lot smoother sounding, but have less character in comparison.

Anyways, they are indeed unique amps. Every element in the pre-amp design is quite different from the norm for guitar amps: the FAC knob, the tone circuit, the coupling cap values, the phase inverter. It's a unique design with a unique sound. I'm not well versed in the history, and I don't know of any first person accounts from Mat talking about the design. I'd be very interested to read any if you come across anything!

It's interesting that you mention Tony Emerson and the HQ20. I had never heard of that, but I looked up some schematics online and don't see any resemblance at all to Oranges. The Matamp site, however, says that Tony and Mat were partners in the early stages of Matamp. Matamp's account of how things started is also a bit different from the article linked above from the Orange site. Matamp even takes a dig at Orange...

"In 1971, Orange Matamp outsold Marshall, and gave Cliff Cooper a taste of volume sales. However; Mat was not prepared to forego quality standards in favour of mass-production, and so Orange amps moved away from the company that designed the originals.

In other words, If you want mass-produced, then… ; if you want hand-built, uncompromising quality, then… Matamp."

From:
http://www.matamp.co.uk" onclick="window.open(this.href);return false;


People that would know more info are:
-Members here
-Members on the Plexi Palace forums (which are pretty dead these days and most of the member post here)
-Joel from Electric amps
-Jeff Lewis at Matamp
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