Amp tinkerers and people who aren't afraid of 700 volts or so in here....

Moderators: Slowy, Capt. Black

User avatar
BY Reg18
#764014
]After playing Matt’s Plexi at gearfest ive been counting my penny’s and as usual I’m miles off being able to afford one.
However I came across a mod to the 5e3 circuit which makes it fairly close apparently.
I’d leave the bright channel as it is because it’s awesome and shouldn’t be touched. However I never play the normal channel and rarely blend it in with the bright.
So for not a lot of money I could convert my normal channel to Plexi style circuit.
Should I?

I’ve already had Baja Electronics install a MV on the amp and a 3 way NFB switch so it’s not unmolested anyway.
Will modding it further devalue it more?

User avatar
BY Reg18
#764026
kdawg2a wrote:MOD IT!!!!!!!!!! Any amp that can do tweed and brown is a valuable amp in my books.


For not a lot of $$ it would sure make it more useful to me, hopefully others would see it’s value as well.
User avatar
BY jeremyb
#764028
Another vote for modding it, looks like an easy change!
User avatar
BY calling card
#764029
I'd imagine a 6V6 based plexi would be something you could push without so much destruction of your hearing system. I have no idea how invasive it would be on the stock layout. Not something I'd do to my 5E3.
User avatar
BY kdawg2a
#764030
That mod does sound pretty good but don't forget part of the reason the plexi sounded so good was it's big and loud and moves some air. I think a smaller watt amp will always struggle a little to capture that.
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BY RectifiedAmps
#764033
The demo makes the mod sound good, but I'm against calling it a 'Plexi' mod. The mod is jigging with just the first gain stage which makes a difference to the simplicity of the 5E3 preamp, but is still very unlike a Plexi circuit. The Deluxe has little preamp gain but sounds huge because of how you can overdrive the power amp section - the Plexi sounds huge because of preamp distortion/voicing from twice the number of gain stages of a 5E3. The mod might get the sound close at a particular setting and (most importantly) that might sound great, but I wouldn't expect the amp to 'behave' like a plexi. But if it's a simple mod and you don't like the normal channel, it's worth a try!
User avatar
BY Reg18
#764035
RectifiedAmps wrote:The demo makes the mod sound good, but I'm against calling it a 'Plexi' mod. The mod is jigging with just the first gain stage which makes a difference to the simplicity of the 5E3 preamp, but is still very unlike a Plexi circuit. The Deluxe has little preamp gain but sounds huge because of how you can overdrive the power amp section - the Plexi sounds huge because of preamp distortion/voicing from twice the number of gain stages of a 5E3. The mod might get the sound close at a particular setting and (most importantly) that might sound great, but I wouldn't expect the amp to 'behave' like a plexi. But if it's a simple mod and you don't like the normal channel, it's worth a try!


Interesting info, I like the pushed Plexi sound as apposed to preamp gain on full Plexi sound. So it might end up just pushing the 6v6s into fizzy preamp gain territory?
Although as the normal channel is essentially unused modding it to something more useful still might be worth it.
He posts his schematic here, which includes other mods he did as well. As I don’t really know how read the schematic can you tell me if it all looks legit?

https://farm8.staticflickr.com/7474/293 ... 0b8f_b.jpg
User avatar
BY AiRdAd
#764041
what speaker are you using with your 5e3 Reg?

what speakers were in the cab with the plexi?

You didn't get a chance to put your 5e3 through that cab did you?
User avatar
BY Reg18
#764043
AiRdAd wrote:what speaker are you using with your 5e3 Reg?

what speakers were in the cab with the plexi?

You didn't get a chance to put your 5e3 through that cab did you?


Good point, I didn’t try my amp through his cab (which is an open back 2x12 with a Greenback and a Blue)
In my cab on that day I had my Celestion V type but I usually have a Celestion Gold in my 1x12 cab.
User avatar
BY AiRdAd
#764045
How close does the 5e3 through the Gold get when you jumper the channels and turn it up LOUD?
User avatar
BY Reg18
#764048
AiRdAd wrote:How close does the 5e3 through the Gold get when you jumper the channels and turn it up LOUD?


I have tried this but I don’t remember exactly how it compared.
I would say the 5e3 has a looser tweedy vibe as apposed to the plexis stiffer strident punch in the face type feel.
Tone wise I couldn’t confidently say how much difference there really is as it’s been a while since I tried this.
I am in the middle of building a detuned closed back 1x12 cab which might help to get closer to the feel and punch.
BY godgrinder
#764050
Reg18 wrote:I would say the 5e3 has a looser tweedy vibe as apposed to the plexis stiffer strident punch in the face type feel.


A lot of that comes down to tube VS SS rectifiers, assuming the plexi you tried was a JMP.
User avatar
BY Reg18
#764054
godgrinder wrote:
Reg18 wrote:I would say the 5e3 has a looser tweedy vibe as apposed to the plexis stiffer strident punch in the face type feel.


A lot of that comes down to tube VS SS rectifiers, assuming the plexi you tried was a JMP.


Not sure which model it was, it’s this one.
https://i.imgur.com/5E6dDBQ.jpg

Image