#1
Hey guys,

I've been playing with this little Peavey Classic 20 for a while now and I've decided that she needs a little love and some upgrades.

I'm not very technical with circuit board mods so I thought I'd focus on the easier mods that I can nice and easily. I did some research on various pages and the most popular mods on these amps is simply to replace the speaker and the tubes.

For the tubes, I chose Eurotubes.com. These guys are great because they make sets of matched tubes for different amps. This is great because you just jump on, pick the amp and pay for them. You can even request a set that are: hot, mid or with more headroom. I went with the mid level set, I wasn't looking for too much gain, but I did want some breakup there. The kit I got included 2 EL84 power amp tubes and 2 ECC83 S preamp tubes (replacing the old 12AX7A’s that were in there. Both the old and new tubes are JJ Electronics tubes, but the old ones are pretty damn old so there should be some tone change.

With the speaker, I chose to go with Jensen. Not only were they the most recommended on the various forums of people modding their amps, but Jensen's website has audio examples of each speaker, which is really handy when deciding what you want. I ended up going with the P10Q model. This is a 10", 40W, 16ohm speaker. I chose this for it's clear tone and warm breakup at higher gains.


Testing

I recorded the amp with no mods, changed the tubes and then with changed tubes and changed speaker. I also recorded 3 different parts each time: one mid gain, one low gain and one higher gain (in hindsight, I should have probably recorded the mid gain a little hotter). I used a Rode K2 tube condenser mic into an RME fireface preamp. Excuse the crappy guitar playing, I was more interested in hearing tone differences that good takes.

Low Gain
Master: 12 o’clock
Treble: 9
Mid: 4
Bass: 4
Volume: 2
Boost: On
Guitar: Gibson BFG
Pickup: Neck P90
Guitar Volume: 5
Guitar Tone: 10

Mid Gain
Master: 12 o’clock
Treble: 12 o’clock
Mid: 12 o’clock
Bass: 12 o’clock
Volume: 4
Boost: Off
Guitar: Gibson BFG
Pickup: Neck P90
Guitar Volume: 5
Guitar Tone: 10

High Gain
Master: 5
Treble: 12 o’clock
Mid: 12 o’clock
Bass: 8
Volume: 9
Boost: Off
Guitar: Gibson BFG
Pickup: Bridge P-Rails (Humbucker)
Guitar Volume: 10
Guitar Tone: 10

Here are the files:
https://www.dropbox.com/s/ckpj6fpf50j1az6/Peavey%20Mod%20Samples.zip?dl=0


Conclusions

One of the bigger differences in the files is the volume between each one, which I was quite surprised at. I didn’t normalize them, to show how much different they were, but you can do that on your own if you’re interested.

I found that the new speaker got rid of a lot of the boxy tone that’s associated with the amp, however it came up a little too bright on the heavier tones, easily EQ’d out but I kept the levels the same for the sake of the experiment.

The tubes also added quite a bit of high end and detail that weren’t there before, which was pretty interesting. It might be too bright, but again, that can be EQ’d out. Also good to note that the tubes are brand new, so they haven’t been “broken in” yet.

I am yet to see if I’m completely sold on the mods, I’ll have to really take em for a test drive with the band and play around a bit more, but I am liking the less boxy, more open high end sound.


I’m interested to hear what you all think.
#2
It is funny you think the JJ tubes are bright, to me they are the exact opposite. I find JJ to be the darkest sounding new production 12ax7's being made.

Tubes don't break-in speakers do and it may sound very different after 25+ hours of loud playing.

Cool you found some easy cheaper fixes to make your amp better for your situation.
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#3
Quote by Robbgnarly
It is funny you think the JJ tubes are bright, to me they are the exact opposite. I find JJ to be the darkest sounding new production 12ax7's being made.

Tubes don't break-in speakers do and it may sound very different after 25+ hours of loud playing.

Cool you found some easy cheaper fixes to make your amp better for your situation.


Hey Robb, cheers for the reply.

The old tubes were JJs as well and they were really old, so I guess the new JJs are just bright in comparison to the old ones.

I hadn't heard about the speaker breaking in, but I'm pretty interested to see how much it changes... I might even post another recording in a couple of months once it breaks in, just to see how much it's changed.