Want Pre500 tone? Here's how to get it!

[Anonymous]

OK my ears were definitely fatigued... the amp kills! :mrgreen:
It's a monster now... :twisted: Clips incoming later today!

:twisted: Awesome!

The idea of only modding one channel to the pre-500 tone is an interesting one. I wonder if it would retain the good clean tone and the wicked crunch?

I really liked the orange channel with a 500k pot. Awesome crunch - a great balance to the "new" red modern - and cleans are still good. If you left the 250k pot, it might be just a little bright with the smaller cap value later in the circuit, but I didn't try that setup.

 

[JCDenton6]

EDIT: man this sounds so bad, I have another clip coming tomorrow.

Here is my bad clip :lol:
Thats what I get for recording a clip after hitting my arms and forearms hard at the gym today.

http://www.tonefinder.com/index.php?section=id&value=12854

I had settings at noon, presence off and mids dimed.
Amp is loaded with Svetlana EL34's (overdue for a change)
Have a Tung-Sol gold pin in V1. Shuguang 12AX7-B's in V2 through-V4 and another Tung-Sol gold pin in V5
Bold and tube rectifiers (using mesa 5U4GB's)
Man I need some GZ34's

Wish I could open the amp up more, it was recorded at bedroom volumes.

 

[b0nkersx1]

EDIT: man this sounds so bad, I have another clip coming tomorrow.

Here is my bad clip :lol:
Thats what I get for recording a clip after hitting my arms and forearms hard at the gym today.

http://www.tonefinder.com/index.php?section=id&value=12854

I had settings at noon, presence off and mids dimed.
Amp is loaded with Svetlana EL34's (overdue for a change)
Have a Tung-Sol gold pin in V1. Shuguang 12AX7-B's in V2 through-V4 and another Tung-Sol gold pin in V5
Bold and tube rectifiers (using mesa 5U4GB's)
Man I need some GZ34's

Wish I could open the amp up more, it was recorded at bedroom volumes.

I think that sounds good.

On the other hand, if somebody had told me that had come from a Rev. G, I would have no trouble believing it, you know? (my point being that it sounds like a rectifier)

Still if it only took like $10 and 10 minutes that's pretty neat~

 

[JCDenton6]

Thanks man, sometimes I'm very critical of myself.
I recorded another clip with settings at 12:00 but dimed the mids and cut the gain down to 9:00.

http://www.tonefinder.com/index.php?section=id&value=12856

This is a much better recording.
Turns out the gain pots are fine, and I got the knobs on with no problem!

 

[Anonymous]

Nice! I think I like the presence a little lower - not over 10:00 usually - but it sounds badass!

How are you liking this setup? I think a Triple in that configuration might be my "ultimate" Rectifier sound...

 

[JCDenton6]

So far it kicks major a$$! Still can't get over how much clear tight gain I now have. :shock:

It's even tighter using silicon diodes but that brings the voltage high up on the EL34's. I'm going to get me some GZ34's soon. I'm keeping the presence at around 9:00 now and the gain in between 9:00 and 12:00 depending on the guitar.

 

[YellowJacket]

Thanks man, sometimes I'm very critical of myself.
I recorded another clip with settings at 12:00 but dimed the mids and cut the gain down to 9:00.

http://www.tonefinder.com/index.php?section=id&value=12856

This is a much better recording.
Turns out the gain pots are fine, and I got the knobs on with no problem!

This is a crushing avalanche of gain! I can see where Mesa would opt for a 250k pot to make the amp more usable for other applications besides straight up metal. If that is all you want to play, this mod is probably like heaven!

 

[JCDenton6]

Very true, and I have to state that the cleans is more or less the same to me after the mod, just have to keep the gain for the orange channel below 10:00 or it starts to break up (you may have more play with pups that are not as hot)
That clip I only had my gain at 9:00 :shock: I suppose the extra saturation came from my EMG's running at 18V, my preamp/power tube combo, and my heavy right hand :lol:

 

[YellowJacket]

Wait what? Gain at 9:00!?? How much output do those EMGs have!? Does this mod put the gain in Peavey 5150 territory?

 

[JCDenton6]

To me, my triple now has more gain than the 2 5150s I have played recently.
I remember reading earlier in this thread that TheMagicEight (posted on RT as well, that's where I remember reading it from) that he had to run his gain on his 5150 higher to keep up with his "pre 500" modded tremoverb.

The 5150 is excellent, no doubt, though I did have the gain up significantly higher than with the modded Rectifier. In the room, it was close too. The 5150 is just a little tighter, but the Mesa has an awesome low midrange that just makes it sound huge!

 

[Anonymous]

To me, my triple now has more gain than the 2 5150s I have played recently.
I remember reading earlier in this thread that TheMagicEight (posted on RT as well, that's where I remember reading it from) that he had to run his gain on his 5150 higher to keep up with his "pre 500" modded tremoverb.

The 5150 is excellent, no doubt, though I did have the gain up significantly higher than with the modded Rectifier. In the room, it was close too. The 5150 is just a little tighter, but the Mesa has an awesome low midrange that just makes it sound huge!

I honestly think they have similar amounts of gain. I meant that perhaps the 5150 sounded a little more full because I had the gain significantly higher than with the Rectifier.

What I love about the Rectifier now is that you can use most of the gain knob for different types of metal sounds on the red channel. Tight and punchy? Bring it down a little. Tight but with more body? Maybe around noon - 1. And past that? Totally saturated, huge low midrange and still somehow tight and responsive!

And the Orange channel with the 500k pot? Light crunch - chugging rhythm, and everything in between!

 

[JCDenton6]

Man I tell you, converting my triple to these pre 500 specs has really made me pick up the guitar again!
I was previously only playing a handful of times a week, now I can't put the **** guitar down :lol: :lol:

Hope to find good drum software or a drum machine because I'm finally motivated enough to finish writing and tracking the tunes I've been working on

EDIT: Was asked to upload a clip in drop D tuning so here you go, just playing some riffs from "Spieluhr" from Ramnstein and "Byte Block" from Fear Factory. Gain still at 9:00.

http://dl.dropbox.com/u/47381724/Pre%20500%20modded%202ch%20%20triple%20recto%20drop%20D%20riffs.mp3

Tonefinder is being retarded right now so I decided to use dropbox.

 

[psychodave]

I've been interested in the fabled "holy grail" pre-500 tone for years, as I'm sure most are. Through MANY hours of research and testing, I believe I've finally cracked the circuitry code and have found that by swapping TWO parts, your Rev. G Rectifier can have pre-500 tone. Why am I sharing my countless hours of hard work? Because for one, the two parts will take a skilled tech about 5 minutes to swap (and maybe 20 for an unskilled one) and come to a total cost of about $10, not at all warranting the huge amount of money the real pre-500s command. Two, because HOLY HELL it sounds amazing!

So what exactly is the difference in sound? Less flub, bigger midrange, and much more usable gain. At 11:00, the gain is about as much as you'd get from a Rev. G at 2:30 - 3:00. And when you do bring the gain to 3:00 for a huge amount of saturation, it stays tight! What's the drawback? Well, cleans suck again. And the thing is, the stock tone is still awesome. Yes, everything I just said is true, but at low gain settings, the stock setup will be a bit thicker (albeit not nearly as tight). Still, there's no harm in trying this setup, and I highly recommend taking the $10 and ~15 mins and trying it!

Before I get to the mod, here are some clips to show the difference. Please note that I am NOT an expert on recording techniques. These clips are meant to show the difference between the two setups, all else kept the same (except gain settings). No EQ except for a slight high pass filter
Stock
"Pre-500" tone
5150 (for perspective)

I used a Rectifier 4x12, MD421 close, and Studio Projects B1 for the room. Guitar is a Gibson R9 with a BKP Abraxas. Using an Mbox for mic preamps. Settings are as follows:
Treble and Bass: noon
Mids: 12:30
Presence: 8:00
Gain: 1:30 stock, 10:30 on the "Pre-500" (though in retrospect, I'd bring it up a bit in the chorus and down a hair in the verse)
Master: 10:30

The differences are a little more noticeable in the room, but I think they show well enough. Might have had the volume just a little too high.


On to the mod!

1. Change the gain pots to 1MA. Make sure you swap the cap that jumps the two lugs to the new pot.

2. Swap this capacitor to one valued at .005uF, with a voltage rating of at least 450. (0.0047uF Orange Drop is perfect)

This should do it! Of course, changing the Red presence control to a 26k linear would be closer still, but the stock 100k gets you the same sound (just has more presence past 9:00).

If anyone else decides to try this, please share your findings! As for me? I like the Rev. G circuit very much, and would like to have both setups. However, in almost every case, I'd take this Pre500 configuration.

I think that covers everything, though please let me know if I've missed something!

What does swapping out the one cap do? For example, if I only tried the cap...would I hear a difference?

 

[Anonymous]

What does swapping out the one cap do? For example, if I only tried the cap...would I hear a difference?

I believe you would! You'd get a little bit of additional tightness, and a little bit of additional fizz. Essentially, this cap is the difference between the two and (non reborn) 3 channel Rectifiers, although instead of 5nF as with the Rev. C and D, the 3 channel Rectifiers don't have anything. Personally, I prefer the 10nF cap with the stock gain pots.

 

[JCDenton6]

Based on my clips would you say the "pre 500" configuration sounds correct with my triple?
I'm going to slap a fresh set of strings on my guitar and change the batteries (been in the guitar over a year)

 

[Anonymous]

Based on my clips would you say the "pre 500" configuration sounds correct with my triple?
I'm going to slap a fresh set of strings on my guitar and change the batteries (been in the guitar over a year)

Yes I believe so. The only thing about the clips is that the pre 500s could essentially only go to 9:00 on your presence pot, so having it at noon puts your Triple outside the realm of what they could do. Not a bad thing, but also not strictly pre 500.

 

[JCDenton6]

Ah ok, gotcha. I think I'm just stressing the small things now. Later on down the road I'm going to stick some 25k pots in the amp for experimentation.
It's been lots of fun and a great experience thus far. The possibilities are endless I suppose with this :mrgreen:

IF anyone else gives this a go, lets hear your results!

EDIT: Found out what the issue was, apparently I pulled the preamp tube too hard out of the V1 socket causing a small hairline crack near one of the pins weakening the vacuum. Replaced the tube and now I'm in pure tonal mayhem :twisted:

 

[clutch71]

I still don't understand why the change from 1m pots to 250 K pots? That's a pretty substantial swing. Most amps I've come across of similar design use 1m pots...I'm not doubting anyone here...posters did a great job of identifying the pots by posting pics of the reading. Just pointing that out.

The cap being replaced with a .oo47....where is it at on the schematic? What is the value being replaced? Some one with a Rev C, D, F please post what these values are. The codes are right on the Orange drops....Showing me a picture of the cap does not tell me the value or what that particular cap does. KNowing this will tell me what that cap does in the circuit.

Years ago pre500 lore was kept solely to the transformers. This post is the first I've seen that challenges that, and I've been around for a while. Everything I've read in the past is that the transformers for the early Duals were from the MarkIII's used until that supply. Once it ran out Mesa needed a replacment. I'll push it further with something I've never seen about the pre500 transformers....any one ever measured the primary impedance of a pre500 transformer? I'd like to see a comparison of the primary impedance of a pre500 vs a later model. If they are wound the same, in theory this might elimanates the transformer as the fabled back bone of the pre500 tone.

I've owned a Rev G and was never happy with it. I had the peasure of playing many Rev C, D, and F and always liked them better than my G.

 

[JCDenton6]

I circled in where the cap in question is located, in a Rev G that cap has a value of .01uF, on this schematic (Rev F, the cap's value is .005uF which is the same as a Rev C/D/E)
In swapping the cap in a Rev G from stock allows more high end to pass through to the last gain stage, tightening the sound, and resulting in more agressive mids.

The stock cap (.01uF) code reads SBE 715P (400V) 502K 9821
The new cap (.0047uF) reads SBE 715P (600V) 472J 1112

I ordered a few of the .0047uF caps at 600v since the company (mouser) was out of the 400v caps at the time. IT makes no tone difference, just has a higher voltage tolerance.
it appears they made the change to 250k gain pots in Rev F of the recto, since Rev C/D/E share the same tonal range and gain characteristics.
They kept the cap value at C55 the same as the previous revisions until Rev G, when they went with a .01uF there.

As for the transformers... I think they are wound the same way. They look the same to me.

 

[Anonymous]

I still don't understand why the change from 1m pots to 250 K pots? That's a pretty substantial swing. Most amps I've come across of similar design use 1m pots...I'm not doubting anyone here...posters did a great job of identifying the pots by posting pics of the reading. Just pointing that out.

Mesa used 1M pots in the Rev. C / D. They switched to 250k pots for Rev. F and G (I don't know enough about E) for a brighter, less saturated (although more booming in low frequencies) gain. But that was too bright, so they had to remove some brightness from the signal, which happens in gain stages two and three with the 10nF capacitor mentioned. Now that a lot of that high end is gone, the amp sounds scooped, and there's your Rev. G Rectifier sound.

The cap being replaced with a .oo47....where is it at on the schematic? What is the value being replaced? Some one with a Rev C, D, F please post what these values are. The codes are right on the Orange drops....Showing me a picture of the cap does not tell me the value or what that particular cap does. KNowing this will tell me what that cap does in the circuit.

JCDenton6 has this right. However, I would actually say the 1M gain pot is responsible for the more aggressive mids. This is because the 1M pot works in conjunction with the .002uF / 520k circuit directly before to change the frequency response of the entire stage, making it a little darker.

Years ago pre500 lore was kept solely to the transformers. This post is the first I've seen that challenges that, and I've been around for a while. Everything I've read in the past is that the transformers for the early Duals were from the MarkIII's used until that supply. Once it ran out Mesa needed a replacment. I'll push it further with something I've never seen about the pre500 transformers....any one ever measured the primary impedance of a pre500 transformer? I'd like to see a comparison of the primary impedance of a pre500 vs a later model. If they are wound the same, in theory this might elimanates the transformer as the fabled back bone of the pre500 tone.

I've owned a Rev G and was never happy with it. I had the peasure of playing many Rev C, D, and F and always liked them better than my G.

Yes, the pre 500s did use the earlier transformer. However, it has been confirmed that lo and behold, so did Rev. F, and so did early Rev. G. Perhaps they sound better - they certainly sound different - but this is not the only change between revisions, and I'll point to the "Rev. F" schematic floating around to demonstrate my point.

What you'll notice is that this schematic is wrong for a Rev. F. I owned a Rev. F and it definitely sounded different from my late Rev. G, but not that different. No way did it have 1M gain pots. After working for a gear company, it's easy to see how the schematic could be wrong or outdated when they were making these. I think the changes to the amps happened more quickly on the floor than was reflected by schematics. So what, then, is the sound from that schematic? Pre 500.

I've owned a Rev G and was never happy with it. I had the peasure of playing many Rev C, D, and F and always liked them better than my G.

I like Rev. G. I think for grunge, it has an excellent, thick - but not too saturated - sound, and eventually I'll own another. That said, in almost every other application, I like the "pre 500" configuration more.