CALIBER 50 +

[user 7737]

I know if I put the 12au7 in v1 it doesn't effect the volume much but if it is in v2 the volume is way less. I think I will try an 12at7 in v1 as well

i tried the at7 in V1, doesn't effect the general volume at all, less gain but there's something i didn't like with high frequencies... finally the best solution for me is JJ ECC83s in V1 and V5, 12at7 EH in V4 and original mesa's 12ax7 in V2 and V3...

the EH are definitively not my cup of tea...

if i have to change my mesa tubes, someone told me that the sovtek 12ax7wc are very similar to the mesa one... do you know something about that ?

it's weird, those sovteks are quite new and the original mesa i have are from early 90's or late 80's i think...

 

[lpstudio]

I have tried a few brands of tubes and like JJ TAD and sovtek that I ripped out of a traynor ycv40wr. I swapped out the preamp tubes as well to the sovteks and I like the sound with those cheap tubes lol. The tads have a very complex tone but the sovteks smoothed out my tone lots which is strange because they sounded horrible in my traynor. The JJ's in the power section didn't sound good at all but do sound great in the traynor. I guess each amp will like tubes differently lol.

 

[Stonge]

I have one. It's a great amp. I was going to start a thread similar to this, but you beat me. I'm running it like one of the guys above, start with the suggested settings and then work from there.

What cabs are people running theirs through? I'm running mine through a 4x12 with V30's in there... it's got a big mid spike. After the holiday period is over... I'm going to get a couple of G12T75's and run them alongside the V30's in an X pattern. Apparently it should give me a fuller sound.

can I suggest x pattern with EVs and V30s. call me crazy but I think I may have something there.

 

[user 7737]

How many cabs can you run off of a .50 C+?

It's got three outputs, anyone know if you can run 3 cabs from it safely? I've never tried.

I read somewhere the 8 ohm output can't be use together with the 4 ohm outputs...

so, if you want to run several cabs, the better set is 2 8ohm cabs plugged in the 4 ohm outputs

 

[rvschulz]

that is correct ... the amp is not designed to run both 8 ohm and both 4 ohm outputs into balanced loads concurrently ie. 8 ohm out to 8 ohm speaker, 4 ohm outs to 4 ohm cabs.

i don't have my rudimentary physics electricity info at my fingertips and now I KNOW i'm old if i forgot this, but you may need to run to cabs/speakers of higher resistance to balance the load correctly.

you must want to puch a LOT of AIR ... i would consider miking it at some point.

 

[jeid2000]

Yeah, two 8ohm cabs into the two 4ohm outs. I just wondered if the 8ohm out could be used at the same time. Cheers for clearing that up for me.

I'm getting a bit annoyed at my Head just now... I think I need to change the preamp valves cos I'm not getting that distorted sound which I used to have. It's only been since I changed valves. I shall need to investigate.

How do people run the EQ's on their .50?

 

[user 7737]

Yeah, two 8ohm cabs into the two 4ohm outs. I just wondered if the 8ohm out could be used at the same time. Cheers for clearing that up for me.

I'm getting a bit annoyed at my Head just now... I think I need to change the preamp valves cos I'm not getting that distorted sound which I used to have. It's only been since I changed valves. I shall need to investigate.

How do people run the EQ's on their .50?

As i said, i read somewhere you better not use the 8 and 4 ohm out together... i don't find the link where the reason are exposed...

i run the EQ... it's a nice tool... very responsive...

 

[Stonge]

would an 8ohm from the head to an 8ohm cab work if I use the parallel out to another 8ohm cab. Basically head to cab then cab to cab(one cab is parallel out). With both cabs 8ohm and the head using an 8ohm load.

 

[jeid2000]

If you have two 8 ohm cabs, plug both of them into the two 4ohm outs on the head.

 

[user 7737]

would an 8ohm from the head to an 8ohm cab work if I use the parallel out to another 8ohm cab. Basically head to cab then cab to cab(one cab is parallel out). With both cabs 8ohm and the head using an 8ohm load.

head to cab then cab to cab ? is it possible ?

in theory if cabs are 8 ohm and in parallel the total load will be 4 ohm... so plug it in the 4 ohm out of the head... but i think, as jeid2000 said, you better plug each cab in both 4 ohm out...

 

[jeid2000]

would an 8ohm from the head to an 8ohm cab work if I use the parallel out to another 8ohm cab. Basically head to cab then cab to cab(one cab is parallel out). With both cabs 8ohm and the head using an 8ohm load.

but i think, as jeid2000 said, you better plug each cab in both 4 ohm out...

This is correct. It's in the manual :wink:

 

[user 7737]

This is correct. It's in the manual :wink:

yeah i saw it ! but what are the technical reason ? why can't we use the 8hm output together with the 4 ohm outputs ?

 

[MrMarkIII]

Three 8 ohm loads in parallel is 2.667 ohms. You can maybe get away with it, but you're straining the output transformer and prematurely wearing out the power tubes. Not to mention your headroom suffers and the overall tone gets thinner, despite the fact you're running more drivers.

When speakers are connected in parallel, the impedance is reduced. This means that, given the same output voltage, the current demand on the amplifier will be increased.

Basically what you're doing is trying to force more water through the hose than the hose can safely handle.

 

[user 7737]

Three 8 ohm loads in parallel is 2.667 ohms. You can maybe get away with it, but you're straining the output transformer and prematurely wearing out the power tubes. Not to mention your headroom suffers and the overall tone gets thinner, despite the fact you're running more drivers.

When speakers are connected in parallel, the impedance is reduced. This means that, given the same output voltage, the current demand on the amplifier will be increased.

Basically what you're doing is trying to force more water through the hose than the hose can safely handle.

Well well well... so the rule is the same for the speakers and the head outputs ?

i mean, 2 x 8 ohm cabs in parallel total load = 4 ohm
and 2 x 8 ohm head outputs in parallel total load = 4 ohm...

so the 2 x 4 ohm head outputs are in series ! caus' you have to plug them with 2 x 8 ohm cabs ! am i right ?

when i have a look at the caliber 50 + schematic, the two 4 ohm seem to be in series... and the 8 ohm outputs seem to be in parellel with the two 4 ohm outputs (which are in series) !!!

headache... :?

 

[Schmoog]

the 4 ohm outputs are in parallel. actually, all three of your outputs are parallel. which is why you can't use all three at once. the 4 ohm outputs are so labeled because you use them when you have a 4 ohm total load. if you plug three speakers at 8 ohms each then your total load would be 2 ohms, which would stress your OT too much. that having been said, whether you connect both your cabinets directly to the amp, or you go amp -> cab 1 and then cab 1 -> cab 2 using the parallel outs on the cabs, thats fine, and has the same effect as plugging both cabs directly into the amp

 

[user 7737]

the 4 ohm outputs are in parallel. actually, all three of your outputs are parallel. which is why you can't use all three at once. the 4 ohm outputs are so labeled because you use them when you have a 4 ohm total load.

ok... i think i get the point !

 

[user 7737]

for information : (sorry i can't reduce the size of these images)

 

[commaKaze]

I've got the .50 Cal+ 1x12 (6L6/EVM-12L) combo and dig it tons, although it can be limiting.

This month started using STR-440 power tubes at the advice of my tech. They do sound really good. I've used EHX and Sovtek before that. STR-440s sound best of the 3...Sovtek pretty good, EHX blah.

For the preamp, I've just recently nailed a concoction I'm happy with:

V1: JAN/Sylvania 12AX7WA
V2: unmarked US 12AX7
V3: JJ
V4: GE 12AT7
V5: "made in G. Britain" 12AX7A

I had all Svetlanas except JJ in V3 and EHX 12AT7 in V4, and it fizzed and sounded horrific. I can't believe what a difference the tube change made, though obviously understood.

I do wanna trick this thing out a bit. I'm gonna try the yellow jacket EL84 "class-A" thing, as i've been diggin' a lot of amps like the bad cats, SMF, Orange TT... but I really wanna keep the .50+ as there's so much I dig about it.

Also, I sometimes run a Marshall 1960 4x12 with G12T-75s from the 4 ohm out of the amp while simultaneously running the EVM from the 8 ohm...so this is a no no? All seems good...?

 

[MrMarkIII]

"...Also, I sometimes run a Marshall 1960 4x12 with G12T-75s from the 4 ohm out of the amp while simultaneously running the EVM from the 8 ohm...so this is a no no? All seems good...?"


Ohm's law for parallel speaker loads, where:
A = Speaker #1 impedance in ohms
B = Speaker #2 impedance in ohms

(A x B) divided by (A + B) = total parallel load

So, for two 8 ohm loads in parallel:
8 x 8 = 64, 8 + 8 = 16, and
64 divided by 16 = 4 ohms total.

Of course, your Marshall cab is probably 16 ohms, correct?
So, your total load would be...???
(Please show your math...LOL)

 

[mule#1]

You bring up a good point to check your speaker loads. I've found my 50+ doesn't sound as good through (2) 2x12 cabs at the same time. However someone changed some speakers so I should check thatout. I beleive one is a 16 ohm celestion!