Epi Valve Junior Head - Speaker Selection

[Fusioninspace]

I've had my VJ head for about 2 months now. Definately a keeper - great for recording, live, etc... Read the other threads about how great it is.

But here are some of my personal observations concerning choice of speaker on this little guy - and maybe just a comment on speakers in general:

I have two homemade cabinets:

1. 8" - A front-vented (started as sealed enclosure - but whatever) with a single 8" Johnson (Ok, no "Johnson" jokes please). I think the Johnson was made by Celestion for one of their keyboard amps. 8 ohm.

2. 12" - The other cab is an open back with a 12" Line 6 Modeling speaker - "tube" series or something. This is a cab I made for use with my Trademark 10 modeling amp and it sounds excellent with the Trademark. 8 ohm.

So my comment is that the VJ sounds increadable at all volume levels (clean, mild breakup, pushed, etc.) on the little 8" and has very nice volumes for recording and practice. You could feasably mic it for live sound.

On the 12" modeling speaker, it just doesn't get the great tone or mojo that the little speaker has. It will sound OK, but not outstanding like my other cab. It's A LOT louder, but that's the only plus.

So for all you folks thinking about the VJ, just remember the speaker type will make a BIG diff on sound. I don't think it's a size issue. But more of a speaker design issue (lower vs. higher efficiencies, cone material, etc.)

Conversly, my Tech 21 sounds much better with my 12" cab vs. the 8" cab. I assume the "modeling" design of this speaker actually works.

 

[foreverain4]

its quite simple. whichever one sounds the best...

 

[notCardio]

I've been wondering about a cab for this, too

While I want tone, I want it at a minimum of volume (which is why I would want a VJ in the first place). I would have thought that larger and/or more speakers would have been quieter because it would require more power to move them. I would have also thought that a higher impedance load would deliver lower output, but since there are different outputs for different impedances, I'm not sure that this is true.

Any recommendations for a compromise between tone and volume?

 

[rpe]

I’m plugging my valve jr head into a cabinet that I made from an old Fender 2x12 twin 12 combo amp. I bought a few of the cheap 12” Celestion 8 ohm speakers and wired two into the cabinet. It sounds good to me but I want to build another 1 x 12” to try that also.

rpe

 

[notCardio]

I’m plugging my valve jr head into a cabinet that I made from an old Fender 2x12 twin 12 combo amp. I bought a few of the cheap 12” Celestion 8 ohm speakers and wired two into the cabinet. It sounds good to me but I want to build another 1 x 12” to try that also.

rpe

So is that a 4 ohm or 16 ohm load? (series or parallel?)

And would you say it's loud, or not?

 

[cannabis]

i'd think the loudness

would depend mainly on the

efficiency of the speaker

http://www.harpamps.com/micKspeakers/Speaker-sensitivity.html



i'm going to hook mine up

to an evm 12l

good sensitivity at 100db spl

but i'll be wasting about 295 watts

of power handling capability

 

[soundchaser59]

Mine sounds great into a 2x12 that has one Weber Michigan and one Jensen C12K. But it only gives me the sound I want when I crank it to 11.

 

[RideTheCrash]

Newbie question here:

You know how tube amps need a load (speaker) otherwise they'll fry? Would that happen if I took the head and turned it on without it being connected to a cab? Or is that like something that happens in combo amps only?

 

[soundchaser59]

There is no difference between unplugging the speaker cord in a combo amp and unplugging the cab from a head. An amp with no load is an amp with no load, period. Just dont do it....ever.....

Hope this helps, and is not too late.

And did I mention my opinion that the Cannabis Rex is the best Eminence speaker ever made??

 

[RideTheCrash]

Okay I thought so, but I wanted to check. It dawned on me the other day when I was thinking about the amp. I haven't bought the head, so I haven't had a chance to blow it up! Not that I plan to. Thanks.

 

[rpe]

So is that a 4 ohm or 16 ohm load? (series or parallel?)

And would you say it's loud, or not?

4 ohm load, wired in parallel - it's way loud!!!!

rpe

 

[notCardio]

Thanks

but that's just it, I don't want loud. Just the opposite.

 

[cannabis]

but that's just it, I don't want loud. Just the opposite.

so wire two 8 ohm speakers in series

you then have a 16 ohm load

hook it to 16 ohm output for loud

8 ohm for medium

4 ohm for soft



of course, the tone (frequency response) may change

with the impedance mismatches

you just have to try it


but you won't hurt the amp or the speakers

 

[32-20-Blues]

so wire two 8 ohm speakers in series

you then have a 16 ohm load

If you wire two in parallel, that would give you four ohms, right??? Just checking if I understand this correctly.

 

[cannabis]

If you wire two in parallel, that would give you four ohms, right??? Just checking if I understand this correctly.

correcto .

 

[cannabis]

btw, if you wire two speakers

make sure they are wired in phase



most speakers have

a distinguishing mark on one of the lugs

usually a red dot



if they are identical (same brand) speakers

you can probably be confident

the dot indicates the same polarity



for parallel, wire red to red

and unmarked to unmarked

and the wire leads to a red and an unmarked lug



for series, wire the red on one speaker

to the unmarked lug on the other

then attach the wire leads to the two unused lugs



to determine unmarked speaker polarity

touch (briefly) a 9v battery between the two lugs

so that the speaker cone moves outward

(turn it around if the cone moves in)

mark the lug touching the + battery terminal as positive


then touch the battery to the other speaker's lugs

so the cone moves outward, and mark the + terminal positive

 

[hiwatt357]

There is no difference between unplugging the speaker cord in a combo amp and unplugging the cab from a head. An amp with no load is an amp with no load, period. Just dont do it....ever.....

You know...I've heard about this, and I usually have no reason to unplug a speaker cable from an amp; however, the other night, with the volume all the way down, I unplugged the Marshall cab I had hooked up to my Valve Junior and maybe 10 seconds later (probably less) inserted the cable for my HIWATT cab. Then after a bit I repeated the process to switch them back.

Again, the amp was without a cabinet for no more than probably 10 seconds each time, but is that enough to do any damage?

 

[ggunn]

You know...I've heard about this, and I usually have no reason to unplug a speaker cable from an amp; however, the other night, with the volume all the way down, I unplugged the Marshall cab I had hooked up to my Valve Junior and maybe 10 seconds later (probably less) inserted the cable for my HIWATT cab. Then after a bit I repeated the process to switch them back.

Again, the amp was without a cabinet for no more than probably 10 seconds each time, but is that enough to do any damage?

As long as the volume was all the way down, you didn't hurt anything. Even if it were turned up, if you weren't playing, then you wouldn't hurt anything; it's when the output section of the amp is generating big voltage swings into no load that damage can be done to the output transformer and/or power tubes.

If you were playing, then how much you had the guitar and amp turned up, how hard you were hitting the strings at the time, and how long you ran it that way all come into play; the hotter and longer you run the amp into no load, the worse it is for the amp.

 

[soundchaser59]

As long as the volume was all the way down, you didn't hurt anything. Even if it were turned up, if you weren't playing, then you wouldn't hurt anything; it's when the output section of the amp is generating big voltage swings into no load that damage can be done to the output transformer and/or power tubes.

If you were playing, then how much you had the guitar and amp turned up, how hard you were hitting the strings at the time, and how long you ran it that way all come into play; the hotter and longer you run the amp into no load, the worse it is for the amp.

Man, I hope you're right about all that. So how do I reconcile all that with what I read about Class A amps always running maximum power no matter what? I'm no expert on tube power amps, but I just cant bring myself to risk unplugging that speaker even for a few seconds to switch cabs.

And I cant believe how much better my VJ Combo sounds now that I put a 25 watt Jensen speaker in there. It's like a totally new amp now!