NAD: Dual Recto R01xx

[LesPaul70]

Not exactly a "new" amp since it is more than 20 years old but anyway...

Being the lazy (make that "busy" 8) ) guy I am, instead of modding my G, I went and got me an original C, serial R01xx.

Now the problem is...I was seeking to sell my G - but unfortunately (fortunately?), the C is so different from the G that I really need them both. They are far more different from each other than any two Mark amps I have ever owned. The C is brighter, more aggressive...but more than anything else, ultra-tight. It is so tight and focused, it makes my Marks sound like loose mud, relatively speaking. It's like the polar opposite of my G.


It was an interesting shootout session, by the way, when I bought the C. I took my G with me to compare it with the C, and seller also had an F Racktifier. I played all 3, and it was fascinating to hear how each revision had a very distinct voice.

Below, two amp family photos, from the oldest to the youngest.

 

[JCDenton6]

Congrats man, nice score!

 

[LesPaul70]

Thanks!

You know, after reading here that the C isn't really that different from a G at all and you can get C-like tones from the G if you crank the presence, I was genuinely suprised at how different they sounded (and especially played) in a direct A/B test. True, you can capture some of the C timbre with a G - but not its tightness and focus. No way. Not without an OD pedal at least. Presence cranked, the G still sounds very loose, just a brighter kind of loose. (Similary, you can't get the huge, bassy 'wall of sound' of a G from a C.)

Not saying that either is 'better' than the other.
I couldn't make up my mind and ended up keeping both. :| Oh well.

They just have different applications where they shine.

 

[Shemham]

Congratulations for the amp and thanks alot for the comparison. I'm very happy to find any reviews of the Rev C Rectos as It'd be extremely difficult to find them around here for a test.

Could you explain how you should dial Rev G Recto to make it sound close to Rev C with all the settings (EQ, gain) dialed to 12 o'clock? And if you have any experience with the 2010 Multi-Watt Rectos, how would it compare to Rev C?

Thanks for any help here

 

[LesPaul70]

Could you explain how you should dial Rev G Recto to make it sound close to Rev C with all the settings (EQ, gain) dialed to 12 o'clock?

I'm actually not sure if that is even possible. :|
The whole idea that one can make a G sound like a C by cranking Presence is something I read here, from a more experienced and knowledgeable poster than me (possibly Silverwulf?). With my recent experience, I'm not sure I fully subscribe to that idea.

I did try though, and the best advice I can give is turn down Bass (maybe even all the way down?), crank Presence (maybe all the way up), and increase Treble, at least slightly. That ought to get you in the ballpark of the revision C timbre.
But the distortion character of the G will still be totally different from the C. A revision G will always sound loose and unfocused, while a C will remain tight and focused even if you max the Gain.

I have never played a Reborn myself, just heard bands use them, so I cannot really say how they compare. My gut feeling is that they capture something of the brightness and aggression of a C but their fundamental character is still nowhere as tight or focused.

Incidentally, I've just posted a longer version of my original message on the TGP, if you are interested:
http://www.thegearpage.net/board/showthread.php?t=1406978

 

[Shemham]

Thanks, dude! Very informative reads. I've been trying to research Rev C model because it seems to be have been the favorite guitar amp for Allan Holdsworth. When you consider his lead tone preference, the standard Recto tone seems to be out of the ballpark whereas Rev C as described would seem to pretty much nail it.

You said that with the rev C the gain can be dimed and it still stays tight and focused. Does this mean that rev C has less gain on the tap or rather is it just related to having less bottom-end?

How big difference there is between the red and orange channels? Please correct me if I'm wrong, but to my understanding the orange vintage shoudn't have the drastic difference in the perceived brightness compared to Rev G, but just rather the urgent attack and more mids.

Thanks again!

 

[LesPaul70]

it seems to be have been the favorite guitar amp for Allan Holdsworth.

Yes, I too remember reading that in an interview a few years back. A Recto is not something you would associate with Allan Holdsworth, but he did indeed mean a revision C that he had owned and then sold/lost.

You said that with the rev C the gain can be dimed and it still stays tight and focused. Does this mean that rev C has less gain on the tap or rather is it just related to having less bottom-end?

It most certainly has at least much gain to offer as the G. But its gain character/structure is different. It may have something to do with the tighter lows but even if you turn your revision G bass to zero, the G will still sound looser and fuzzier. So it goes deeper than that, and must be somehow related to the transformer/circuit differences.

Perhaps the best way to describe the difference is that the C sounds like you had an OD always on, greatly tightening the tone. (Of course that's not something you would want on your clean channel...)

How big difference there is between the red and orange channels? Please correct me if I'm wrong, but to my understanding the orange vintage shoudn't have the drastic difference in the perceived brightness compared to Rev G, but just rather the urgent attack and more mids.

I would say you are on the right track there. The difference between Orange and Red is much less marked than on a G. Also, the difference between Vintage and Modern isn't that big really - Vintage Orange still sounds pretty 'Modern', due to the inherent nature of the amp.

 

[Shemham]

Yes, I too remember reading that in an interview a few years back. A Recto is not something you would associate with Allan Holdsworth, but he did indeed mean a revision C that he had owned and then sold/lost.

Yeah, I believe he stopped using and sold it as the backline dealers couldn't provide him with the original Dual Rectifier on tour after the Rectifier was further developed. Guess he wasn't too happy with the bottom-end heavy looser response.

It most certainly has at least much gain to offer as the G. But its gain character/structure is different. It may have something to do with the tighter lows but even if you turn your revision G bass to zero, the G will still sound looser and fuzzier. So it goes deeper than that, and must be somehow related to the transformer/circuit differences.

Very interesting. I guess most of this difference can be tracked to what is discussed in the pre500 mod discussion. At least the better response seems to be related to the lack of LDRs that are used to create the Rev E-G clean channel and the minor value difference in the high-pass filter circuit after the V1. I still can't but wonder if there were other minor component changes that can't be easily spotted from the pcb scans available on the Internet if the orange channel is much brighter also.

The question how much the Mark III transformers influence the tone of the early Rectos is still somewhat open to me. Rev F are told to lack some of the bottom-end compared to rev G and in the past this was mostly linked to Mark III OTs. Yet I've heard that some Rev F models share same the same OT with Rev G, but still are practically same as the ones with the Mark III OTs. This makes me think that the difference is related to some underlying yet undetermined circuit difference rather than the OTs.

Oh well, it seems I've hijacked this thread with all this revision curiosity. :lol: I still find it quite a shock that the difference with Rev C would be greater than between different Mark models. I hope that someone from MB would one day give some exact data on the topic to quench the thirst for knowledge and finally close the case.

 

[LesPaul70]

Update (in case anyone is interested)...

Had the first chance to slightly crank the amp in a band context yesterday. Before that, I replaced the mismatched outer pair of power tubes with regular Mesa 6L6s (left the perfectly working inner pair of matched Svetlana =C= 6L6s in).

First impression: man, this amp is bright and tight even cranked! Very percussive and focused, totally unlike my revision G. Well, maybe not totally unlike, as you will see in a while.

It certainly cut through well enough. The Orange Vintage and Red Modern sounded much more different from each other at band volume than they were at bedroom volume. But the Orange Vintage was still more focused and tighter than anything the rev G could offer.

The cleans. We do a couple of clean or semi-clean songs, and I was expecting these to be a problem. I had brought my Mark V with me as a failsafe in case the rev C failed to deliver for these songs (or, for some reason, decided crap out due to tube failure or whatever). Yeah, as such the rev C cleans were indeed unusable for either of these purposes.
For pure cleans, I first added a TC Electronics Reverb. So instead of weak, thin, lifeless 'ping-ping' cleans, I got weak, thin, lifeless 'ping-ping' cleans with reverb. Not terribly exciting. But when I added a very wet chorus effect, things started happening. The chorus masked the sterile nature of the cleans when mixed with the other instruments, and the reverb added nice atmosphere and feel to them. Nowhere near as nice as what I could have got from the V but definitely not unusable with a band.
For the not-totally-clean cleans, I used the Plexi mode of the Bogner Ecstacy Blue pedal, with and without a TS808 clone pedal instead. Worked like a charm.

The biggest problem I had was with the bright, tight, percussive nature of the amp, especially on Modern Red. It not only sounded too piercing and a bit too stiff and brittle to my taste but it also was too merciless to my sloppy playing. Not a single poorly articulated or mistimed attack went unnoticed. They really jumped out. This amp is not for sloppy players...

As for the harsh, trebly 'ice-pick-in-your-ears' highs, I suspect that has to do with the Mesa 6L6 tubes. I had previously swapped the very same tubes out from my Mark V because they made my ears bleed and rendered the channel 3 Bright switch unusable, especially at band volume. Now I hear same issue in the revision C Dual (and didn't before I put in the pair of Mesa 6L6s). I will probably replace them with something else at some point - suggestions and recommendations are welcome!

Fortunately, I could tame the ear-piercing highs somewhat and make my tone more agreeable (and forgiving! :wink: ) with the B/M/T and Presence controls. I also experimented with my MXR 10-band EQ in the loop and made an interesting observation: if I boosted the low frequencies a bit with the EQ, the sound was almost a dead ringer for my revision G! It was still tighter and more focused, though. Except for the lows, they were maybe a little bit mushier than before but, otherwise, it was still the characteristically tight and well-defined revision C tone - while at the same time every bit as massive and crushing as the revision G sound. So if you ever need to emulate the revision G sound on a revision C, you could try boosting the 31.25 and 62.5 hertz bands with an EQ (I used a 6 decibel boost), and turn down Presence to taste.
Obviously this won't change the tight feel of the amp but you can at least bring its timbre pretty close to what a G sounds like.

 

[Elpelotero]

Your observations on the Revision C are all spot on. I noticed the same things years back when I had one. I decided to keep the Revision D as I found it to be just as tight as the C with a little of the brightness tamed off. The E is just like the D, with a boost in the clean channel volume. Then the F and G is where things start to change more drastically. Better cleans, more rounded/looser gain structure. Then came the 3 channel, then the Roadster, Road King, and the Reborn. Lots of flavors to choose from!

 

[Shemham]

My thanks for the new information. I think your topic has provided the most accurate and understandable descriptions of the rev C Rectifier in the Internet. Although there must be loads of nearly mythological bullshit surrounding the early Rectifiers, there truely seem to be some substantial differences, whether good or bad depends on the player. The SLO similarities seem to persist.

Do you feel that the Orange vintage is also brighter than its rev G counterpart or rather just lacks the extra bottom-end? Just wondering as the current view is that Red channel on the rev C should have 220-250Kohm presence pot whereas Orange channel should have ~25k presence pot, hence it shouldn't be much brighter despite being tighter and more focused.

Although the pre500 mod topic has already covered some of the key differences between Rev C and later models, I'd still like to keep researching the board. If anyone has or could take some very high resolutions photos of the rev C and G board and would be kind enough to PM/upload them for me, I'd be extremely grateful. The ones I found around the internet are not of sufficient quality and are very difficult to use for any PCB difference comparison. I've been trying to coax Mesa to provide some more technical data on the differences, but so far they've mostly played down the differences and evaded the question.

 

[JCDenton6]

My thanks as well for the review!

 

[LesPaul70]

Since several people have been interested in the pot values, here's what I can offer so far.

I did some minor pot servicing today. I checked the pots with a multimeter, and here are the values I got when the pots were fully closed (i.e, maximum resistance - when fully open, it was, naturally, usually zero). Of course these are only 'in-circuit' values. I would have needed to desolder the pots to get independent measurements.
If you have other suggestions how to measure the pots, please let me know and I'll try. (But I don't want to desolder them.)

Orange Channel:
Master: 180k
Presence: 22k
Bass: 961k
Middle: 21k
Treble: 227k
Gain: 232k

Red Channel:
Master: 170k
Presence: 237k
Bass: 900k
Middle: 24k
Treble: 237k
Gain: 230k

Loop active master volume: 221k

The pot values were not marked on the pots. There were some minuscule markings but my eyes were too old to decipher them. Fortunately, my son had a much fresher pair of eyes and he could read some of them. The rest were blocked by wires and other parts.
It seems to me that these are simply part codes:

Orange Channel:
Presence: 59???520ROC
Bass: 2937592150ROC

(??? means that part of the code was blocked by wires and unreadable)

Red Channel:
Master: 592-9250ROC
Presence: 5927382150ROC
Bass: 5927381250ROC
Middle: 5927379150ROC
Treble: 5927???88150ROC
Gain: 92???ROC

I also took some gut shots before putting the chassis back in. I can post them later if there's interest.

 

[Shemham]

My gratitudes for measuring the pots.

Only the master volume pots seem to been influenced by other parallel components. The readings you've measured certainly confirms what has been deduced back in the pre 500 mod topic (or actually even before that): the key reason for the bright nature of the Rev C is the high presence pot value on the Red Channel. Rest of the perceived brightness is related to the difference in the first filter network after V1 and the lack of LDRs on the cathodes of certain preamp tubes used to tailor the clean sound on the models after rev D. I guess the Mark III OT and different value choke still play some part in this equation.

I'd still be interested to see the shots of the board.

 

[JCDenton6]

Thanks so much for measuring the pots, I'd be interested in the pics as well

Still iffy on the gain pots... on this video of a Rev C the poster said he had his gain set to 11 o'clock which would suggest that it has a 1 meg pot for gain... :?

I'll have to try 250k pots for gain and see if my 2 ch Triple matches this tone, it's scary close though.

http://www.youtube.com/watch?v=bFEYSS3DnDA

 

[YellowJacket]

Even with that terrible camera mic, it is obvious that the Rev C is an overwhelmingly bright sounding amp. My Rev F is quite bright (for a Recto) but it's nowhere near bright and tight like this amp is. It sounds like Mesa made some big changes with the Rectos after they first released them.

 

[LesPaul70]

Here are some pics. Unfortunately, the hosting service decided to downsize my images when I uploaded them. So if you need a higher-res version of a specific pic, let me know and I'll see what I can do.

The chassis, removed from the shell. (Those EHX preamp tubes need to go...)

Overview of the insides:

Some details:

 

[JCDenton6]

Thanks for the pics!

 

[Dr.G]

Hi,
think I can chame in to share some thougths about the pre-500 topic. I'm a longtime lurker and the main reason why I don't post that much is that I'm no native english speaker.
I mostly can confirm everything that was said about the tone of those amps. They are very percussive and unforgiveable, every time you hit the strings not exactly, you hear it! On the other hand, if you play exactly, you are rewarded with a very agressive and clear tone.
Currently I own a Rev C and D and those amps (at least for me and at least my two models) sound the same. I was comparing them with an A/B switch into a mesa OS 4x12 in stereo with the same poweramp tubes (6l6 str 430) and the same preamp tubes to exclude any possible factor that could influence the tone and I was able to dail in the same tones. The biggest difference were made by the tubes itself. I exchanged the wohle set of tubes of one amp with the other.
For me, this shows how minor the differences are between the two revisions as it seems that the differnces inbetween the same tube brands makes a bigger effect.
I had the chance to compare the Rev D to a Rev E and the characteristics of the amps were the same. I had a slight impression that the Rev E sounded a little bit more 3D, but again this could be caused by different tubes.

@LesPaul70: I would really be interested in hearing your thoughts about how the Rev C compared to the Rev F Rackto...

 

[LesPaul70]

@LesPaul70: I would really be interested in hearing your thoughts about how the Rev C compared to the Rev F Rackto...

The F Racktifier was in many ways a cross between the C and the G. It offered the percussive attack and the brightness of the C but the sustaining sound was definitely looser than that of the C. In other words, it lacked the tightness of a C, and also lacked the huge, bassy 'wall of sound' of a G.

We tried to dial all 3 amps similarly, initially all pots at noon, then different combinations. The sound of the F was very bright, aggressive and in-your-face (but not tight like the C). To be honest, in the end, we agreed that the F Racktifier sounded much inferior to the C and the G. We just couldn't dial in a great tone from the F. But I acknowledge that could have been entirely the guitarist's (my) fault. I could easily adjust my playing style to take advantage of the C tightness, and was already very well versed in the dark, loose G sound and knew how to exploit it. But nothing I tried really worked with the F Racktifier sound - my playing just sounded very harsh and in-your-face, in an ugly way, through the F.