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

[AdmiralB]

Yeah, it's tough to keep track of this stuff. On the Mark IVs, they just tape off the 5V windings.

 

[screamingdaisy]

Yeah, it's tough to keep track of this stuff.

Yes, but I got to learn something new in the process.

 

[Third Age Amps]

You and MagicEight are officially the Boogieboard mythbusters. It figures that the difference in tone is actually due to a couple of caps and resistors, not some magic output transformer. I'm sure the output tranny colours the tone somewhat but picking which frequencies to bleed from the gain pot will definitely have a far more drastic effect.

Thanks, I guess we are. :lol:
I think after I figure out the process of rewiring the 1st gain stage (think I have to pull out the bottom LDR's and replace them with dual lead LDR's) and pull out a few more resistors (if they impact the gain signal at all) this will be a full on "pre 500" mod. (although it's really, really close at this point)

Just wish I had a full schematic of a Rev G, I snagged the one of the Rev C TheMagicEight posted, I think I am finally getting the hang of reading and understanding them.
Looks like we're close to figuring this out. Thanks for your input on the tranny issues AdmiralB, I didn't realize that Mesa did that.

Will you make up a parts list or instructions showing your procedures? You could probably make some good money selling "Pre-500 Mod Kits" on the Bay.

 

[JCDenton6]

It's something to think about, but I would want to make sure it's 100% accurate before then.
I'd love nothing more than a pre 500 owner (past or present) to play on my Triple and give me feedback.

 

[JCDenton6]

Gentlemen... I think I got it!!! The gain and drive I am getting now sounds like pure Pre 500 tone! You have to hear this :twisted: :twisted: :twisted: :twisted: :twisted:

I'm bringing my Shure SM57 back home from our studio and I'm throwing up some clips.

 

[JCDenton6]

Promised clips:

http://www.tonefinder.com/files/32-Steel%20Messiah.mp3

http://www.tonefinder.com/files/25-New%20Clip.mp3

I think the amp really came alive even though these aren't the best recordings (I just placed the mic against the grillcloth 1 inch left of the dustcap, wish I had more time for better tracks but I have a gig tonight)
What do you guys think of the changes? I feel that the amp became even tighter and more aggressive with more attack.

 

[YellowJacket]

Ya, sounds more urgent / aggressive while simultaneously sounding more clear / less fizzy. How does this compare with a 5150?? It's definitely much more METAL and less grunge.

 

[JCDenton6]

I really like my triple better now than the 5150 I used to own.
It just sounded more articulate and complex even though the gain structure was over the top on the 5150.

Now since I have tweaked my Triple out (I'll have the photos up tomorrow I hope) it seems to have the gain level of the 5150 but retaining that clarity, articulation and complexity in the tone I like about the rectos.
Not to mention the evil sounding low mids! :lol: :twisted:

I just gotta take it to the studio we practice in so I can really crank the volume and record it better (damn living in apartments) :evil:

 

[Elpelotero]

I'll be honest.....



That second new clip was effin' good! Sounds scary close to my amp.

 

[YellowJacket]

The Early Dual tone is SICK! It really was a full on metal amp at first.

 

[Yetti]

I believe now, that second clip was crazy broootal, so clear and articulate and crunchy.
Would love to hear it recorded in band volume/settings. Ive been experimenting with my Triple getting that same Clear and articulate awesomeness recorded.

 

[JCDenton6]

Sweet guys, that sounds good to me! Thanks for the feedback. I had settings at noon and gain at 9:00 with no boost even though it was recorded at low volumes.
There is still 2 changes I have to make to bring it to exact Rev C specs (hopefully)

 

[JCDenton6]

Ok, here are some pics with explanations:

Remove R277 and install a jumper.


Remove R272 and install a jumper.


Remove R271 and install a jumper.


Remove R110 (680k) and replace with a 470k, remove R322 and C10



This is as close as I think you can get to Rev D/C tones (just run your presence higher)

Here is another clip with better mic placement, sadly I couldn't crank it but the tone comes through better, just playing some riffs from Rosenrot by Ramnstein:

http://www.tonefinder.com/files/76-Rosenrot.mp3

 

[KillDivision]

Please check this tread and reamp the included DI tru the preamp of your pre500 modded recto.

http://forum.grailtone.com/viewtopic.php?f=24&t=60496

 

[Anonymous]

Remove R110 and install a jumper.

Wouldn't recommend doing that! I'll be the first to say if it sounds good, it is good, but that resistor acts in conjunction with C9 to form a high pass filter, as well as with the gain pot later to shape the frequency response of the 1nF cap on the pot. I'd expect too much (muddy) gain by jumping that resistor.

 

[Anonymous]

I've been working on my Dual Rec clone a little today. First, I need to mention that the clips I posted at the beginning of this thread require one more thing than what I had previously realized. Tremoverbs, for whatever reason, don't have a 20pF cap before V2a (C12, I believe). Removing this with the 250k gain pot may not make a huge difference, but with the 1M pot it does. Highly recommended.

To get boosted Rectifier tone, then (without using a boost), I'd recommend 1) changing the gain pot to 1M and 2) lifting C12. This is the tone you hear in my clips, and in the room, it's awesome.

At this point, it seems that the most noticeable ways the Pre500 amps - at least Rev. D - differ from later revisions is the following:

1) No LDRs on the cathode bypass caps

2) Different (smaller) Mark III transformers

3) 220k presence pot

This is my guess, FWIW. From my experience, removing the LDRs and maybe lowering the bass just a little will get you pretty damn close. Nothing scientific, but it seems to work for me. And on the 3 channel amps, it should be even easier. Simply jump the 100 ohm resistors on the cathodes.

 

[JCDenton6]

I'm going to have to try the 220k pots for presence down the road as well.

 

[Anonymous]

Here's a clip I made of my clone. This has no LDRs on cathodes, 1M gain pot, 470 ohm screen grid resistors, and no 20pF cap.

 

[JCDenton6]

Man that sounds really good!

 

[JCDenton6]

I removed C10, C12, changed R110 from 680k to 470k and removed and jumped R322 and this was the result...

http://www.tonefinder.com/files/40-Open%20A%20Clip.mp3 :twisted:

Just some Fear Factory inspired riffs, same settings as before but think I should've lowered the presence a bit.