Cannabis Rex In Ampeg Reverbojet--Outstanding!

[Radspin]

After reading a number of posts on this forum and taking the advice of Bill M and others, I bought a Cannabis Rex speaker to put in my 1968 Ampeg Reverbojet, which previously sounded too bright with a 1968 Jensen C-12R and a generic Eminence (from the '70s). All I can say is--wow! The combination is superb. The amp now sounds wonderful, with great clarity, presence and richness, whereas before it was way too bright. It sounds like a sweet, beautiful-sounding amp now instead of being too bright at higher tone control settings (the amp only has one tone control) and too lackluster at lower (less treble) tone control settings.

To everyone who recommended that I get the Cannabis Rex to warm up this amp, all I can say is--thanks! The amp now sounds superb and its clean tone is fantastic (the amp uses 7591A power tubes, a very different and more "hi-fi" sound than anything else I've heard). I can see where this speaker might not work in all applications, but in my Reverbojet, the Cannabis Rex is just stunning.

[mad dog]

That sounds like the right speaker for the job alright. CRexes are so fine. The two in my Twilighter (magnatone) 260 sound so good, such a tonal jump up from the stock alnicos, it's essentially a different amp now. As good as one CRex is, two are even better. One idle daydream lately has me picking up a SF Pro Reverb and swapping in two CRexes (such dreams could get expensive!)

[Radspin]

I just came back from a rehearsal using the Ampeg and the Cannabis Rex and I am the proverbial happy camper, as they say. The amp sounded simply magnificent with the Cannabis Rex, a 2002 Jeff Beck Strat, a Fulltone OCD and Full Drive II, and a Voodoo Lab Micro Vide. I mean, I was in utter tone heaven and I've been playing for 40 years--and spending 40 years experimenting with guitars, amps and equipment. This speaker is just superb.

[HOBBSTER01]

It's all your fault...
I just bought a Cannabis Rex for My '69 Jet.
You people are killin me.
Can't wait hehehe.

[Radspin]

Hobbster,

If you get the same results I did with the Cannabis Rex, you are going to be thrilled.

[Scottone]

just reviving an old thread since I picked up a 68 Reverbojet yesterday.

Great little amp, but I'm finding it a bit bright with the Jensen C12R that's currently installed.

Is the Cannibis Rex still the recommended speaker of choice?

[mojo2001]

I'll step up and recommend it in 7591 Ampegs. I have one that I have used with 1965 Reverberocket R12RB and 1971 GS12-R.

I need another one.

The stock Jensen C12R has a certain charming fizzy bite to it, but these amps can really sing with a better speaker.

I sometimes feel as though I can go one step brighter than the C Rex, especially with the octal preamp R12RB.

I have a reconed vintage C12N coming in this week which I will compare, but the C Rex is staying with one of these amps.

[Scottone]

Sounds like the Cannibis Rex is worth a spin...thanks for the reply

Originally Posted by mojo2001

I'll step up and recommend it in 7591 Ampegs. I have one that I have used with 1965 Reverberocket R12RB and 1971 GS12-R.

I need another one.

The stock Jensen C12R has a certain charming fizzy bite to it, but these amps can really sing with a better speaker.

I sometimes feel as though I can go one step brighter than the C Rex, especially with the octal preamp R12RB.

I have a reconed vintage C12N coming in this week which I will compare, but the C Rex is staying with one of these amps.

[Maradona86]

I got a Cannabis Rex in my Kustom '36 Coupe and love it. My newest purchase, as some may know, is an Ampeg j 20 Jet. Like the Stock sound and don't really have problems with it at all; kinda wish the stock speaker had a bit more headroom. It seems like it's missing something, not too sure what.

After reading this, I'm really really curious what a Cannabis Rex would sound like in one of these newer Ampegs....hmmmmmmmmmmmmmmmmmmmmmm

Oh brother

Here we go again tweakin another amp. Nothing ever stays "stock" in my house.

[Radspin]

I am still really, really enjoying the Cannabis Rex as opposed to the stock Jensen that came with the amp.

The tone control on my Reverbojet (which has been gone over by a tech) acts almost like a second volume control in that when you turn up the treble, the volume goes up quite a bit as well. So, I wind up doing a balancing act between the volume and the tone control to get the volume I want along with the tone I want.

Keep that in mind--it is still possible to get a really bright sound out of the Reverbojet even with the Cannabis Rex, but with the Jensen in the amp, I found that the amp was just too bright at anything but very low tone control settings. This amp is quite different than my '65 Princeton Reverb.

[skeksis]

So, I've got one of these in my small collection now... a '68 model with a couple odd features that look to be 'transitional' from the Golden Glow series. It didn't have any speaker when I got ahold of it... I've dropped a couple misc 12's in there to see what it sounds like. BRIGHT is right. A vintage Jensen C12N was almost painful, as was a vintage Altec. Best compromise from what I've got sitting around is an eminence-made Fender circa 1990 from an old M-80 Chorus SS amp.

So true about the 'tone' circuit affecting the overall volume. Usually, I've been happiest with the tone on roughly 1/3, volume up pretty high... Playing a LP jr, basically it IS the tone you hear in Honky Tonk Women etc... Dang loud, though.

Another note, there's a lot of preamp gain blocked by the tremolo circuit in this thing - I can explain a workaround to get more volume without dialing the tone up so high.

I'm eager to try a good speaker in the thing... tell you what, though, nothing else I've got (or ever owned) really sounds anything like this.

[reverberocket2]

CRex sounds great in my mid 60's Ampeg Reverberocket2

[Radspin]

Skeksis,

That's pretty much how I've been setting the amp--tone around 1/3 and volume turned up!

The tremolo workaround sounds intriguing--what's involved? I don't know if I'll actually want to do it, though, as I absolutely love the tremolo this amp delivers.

[skeksis]

Ok, here's what I've figured out so far... the tremolo circuit on this thing works something like this: off the plate of the first 1/2 preamp tube, the guitar signal passes through a capictor to a 5.6meg resistor in parallel with the photo-resistor side of an optocoupler. the neon lamp side of the optocoupler is part of an oscillator circuit driven by the 2nd 1/2 of the tube. the optocoupler works so that it is ON when the trem is off, which means that the resistor side is low-resistance and the signal passes around the 5.6m resistor to the tone-stack fairly easily. when the tremolo is ON, the lamp flashes on/off changing the resistance value low/high, causing the effect.

Note that the above description is correct to the best of my knowledge, but I'm no expert in interpreting schematics...

When I got my amp, the optocoupler was not really working, so the resistance of the photo-resistor was always stupid high. For kicks, I bypassed that part - and the volume of the thing was huge! After that, I looked all over for specs of the Ampeg part, to see what the right value would be... which turns out to be in the ballpark of 200k ohms (maybe you could measure yours? it's a little tricky to do, though). Effective resistance of the 5.6m and 200k resistors in parallel gets you something like 190k, which really tamps down on the gain from the first preamp stage. Taking a cue from the Fender replacement part (with an ON resistance of about 40-50k), I detached the photoresistor side of the part and soldered in a 56k resistor. Pretty good volume jump. I've been too lazy to buy the fender replacement part... but now I know that there's a lot of gain potential in there that just wants to be free.

Too much info? anyway, easy mod for me to do since I already need to replace that part, and the only real replacement option will have this effect whether I want it or not... probably not worth it if you already like what you're hearing.

[Radspin]

I'm going to take the amp to a gig this weekend and see how it does. (I'm taking another amp also just in case.) If the volume is enough, I'll leave the circuitry alone. Otherwise, maybe I'll ask my tech to do the mod.

[garyd5158]

Hey Radspin,
I put a Cannabis Rex in my Peavey Classic 30 and it was a great choice. Very rich and chimey sounding. The notes come out very articulate. Thanks for the post.

[pistolsteve]

Originally Posted by garyd5158

Hey Radspin,
I put a Cannabis Rex in my Peavey Classic 30 and it was a great choice. Very rich and chimey sounding. The notes come out very articulate. Thanks for the post.

Gary,

I've got a Classic 30 too, and have been thinking about trading out the stock Blue Marvel. CRex was at the top of my list as a replacement (along with Weber Blue Dog or maybe a Hellatone).

What wattage CRex did you put in your Classic 30? Also, I've heard the CREx takes longer to break in than other speakers. Just curious how long you've had yours in, and what your thoughts are on "break-in". Did it sound good right off the bat new, or did it take a while to warm up?

[garyd5158]

Originally Posted by pistolsteve

Gary,

I've got a Classic 30 too, and have been thinking about trading out the stock Blue Marvel. CRex was at the top of my list as a replacement (along with Weber Blue Dog or maybe a Hellatone).

What wattage CRex did you put in your Classic 30? Also, I've heard the CREx takes longer to break in than other speakers. Just curious how long you've had yours in, and what your thoughts are on "break-in". Did it sound good right off the bat new, or did it take a while to warm up?

Well, I just put it in (50 watts, 16 ohms) and have been warimng it up by playing for 4 hours and running a cd player through it for another 4 hours so far. I have yet to crank it up. I ere I need to put about 40 hours or so hours through it to get the cone moving good. I'll give you an update after a few more days.
I don't gig so its jus at medium volume most of the time anyway.
My original speaker just sounded tired and sort of flat or farting sounding. So far this Cannabis Rex in there is a big, happy improvement tone wise. The volume is about the same and I'll turn t up after I break it in.
Sounds good so far, my guess it'll probably just improve.

[Doc]

I have a c-rex in my 5e3 combo. It has been in a buch of amps and has worked great. I just put one in a 1x12 oversized cab with semi-closed back. I had the first one in there previously. I love it. It makes me think I need 2 for my 2x12.

Dale

[Oldschoolwax]

Hmmm. so this will make my 66 ReverbRocket 2 louder too hmmm.... Maybe I can get a way with it after all! I love the Gemini 1 more but don't want to take it out ( mostly cause of it's larger size cabinet ) I just physically cant hump the G22 out anymore, too heavy, even on wheels, they don't float into the car or up a step.

[redstringuitar]

CRex takes about 20 hours loud and clean(ish) to break in properly, it's that stiff hemp cone...worth it though, fantastic driver.
50 watt RMS handling 16 or 8 ohm versions.