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Post by Deleted on Mar 14, 2019 8:49:48 GMT
Lads I need some help here (tried the net but found not answer to this)! My Bugera V55 is rated 55 watts and has 2 speaker jacks in Parallel. Then there is a switch for 4, 8 or 16 Ohms depending on what speaker Ohms you have. Its also written at the back "55 Watts out put amplifier, 4 Ohms min load, jacks paralleled" If the total output is 55 watts it must be only at 4 Ohms switch setting right? The stock speaker is at 8 Ohms so it can't have the same power! Must be less? At 16 Ohms it would be even lesser output in Watts? Am I getting this right or should I just flush the toilet I have noticed the new VOX nutube MV50 amp that has jacks 50 watss at 4 Ohms, 25 watts at 8 Ohms and 12,5 watts at 16 Ohms . Can this be applied to Tube amps as well?
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DefJef
THBC Moderator
Due to musical differences I've decided I can't work with myself any more.
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Post by DefJef on Mar 14, 2019 9:41:06 GMT
As I read it the speaker of a V55 is 70 watts. At 8 ohms of resistance your amp is putting out a maximum of 55 watts at full power in pentode mode - switch to triode and it may be about 40 percent less. This leaves the speaker with a nice safety zone of 15 watts before endangering it's construction. So this amp is designed to have its optimum performance at 8 ohms. If you switch to a speaker with less resistance i.e. 4 ohms, the maximum power from the amp would double to 100 watts and have every chance of distorting the sound and even blowing a 70 watt speaker at full power and you'll be running your amp at full tilt which will stress out its power supply. Also note that doubling the wattage won't double the volume. It would only increase by less than a quarter. If you put a 16 ohm speaker in there the amp's wattage will drop to 27.5 watts max power, your amp will be under powered and a little quieter but this may allow you to crank it a bit to get some more power tube overdrive with some more mids. If you think of it like filling a bath where the bath represents your speaker; resistance/ohms = the diameter of the pipe; the water = your amp and its in a header tank in your attic ready to flow. You would want a pipe diameter that allows you to fill that bath at an optimum rate (in my experience they never do, you seem to have time to go and make a cup of tea whilst waiting, but I digress. It would be better to take a shower anyway. More efficient. Hmm...maybe the shower represents solid state modelling ?). Anyway, you want to be able to control that flow with your pipe diameter/resistance/ohms. Too too big a pipe/too little resistance/too small a number of ohms and your bath/speaker will be full of wat(t)er and overflowing before you can turn it off and you'll have an expensive repair bill and a lot of drying out to do. Plus you may have to visit a carpet shop and rub carpets with your hand and that may make you vomit. Oh no, that's just me.
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DefJef
THBC Moderator
Due to musical differences I've decided I can't work with myself any more.
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Post by DefJef on Mar 14, 2019 10:12:07 GMT
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Post by Deleted on Mar 14, 2019 10:30:04 GMT
I run it at Triode as I dislike the Pentode for some reason. Ok so Im already running 40% less on Wattage, thats grand and exactlly what I need, a large cabinet but less power = more pleaseing dynamics I guess and full bodied sound.
So if Im to use a 4 Ohm speaker in this Buegra V55 what would happen? The amp would suffer I guess as it has a load that ccan't get more than 55 watts total? I think you might be wrong here. Sure the stock speaker is 8 Ohm but that doesn't mean the amp runs at full 55 watts as the switch is on the 8 Ohm setting.
I dont think Bugera would build an amp that needs more watts for the 4 Ohm setting/speaker? Makes no sense.
Any way, I just wondered about my new 8 Ohms Josh Smith speaker rated to 50 watts (Josh stated it can handle more). If Im on Triode that means amp is running 33 Watts at full volume, so Im safe here?
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Post by Deleted on Mar 14, 2019 11:16:14 GMT
I know that link is right and I agree but that link does not explain how Bugera V55 works In case you right that my Bug puts out 55 watts into 8 Ohms then the 4 Ohm switch is there ONLY in case one is using 2 x 8 Ohms speaker and in that case one needs the 4 Ohms switch, or? Ney, this would give 4 Ohms into both sockets , so no good as speakers are in parallel or ?
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Post by Deleted on Mar 14, 2019 12:16:55 GMT
Yes Im wondering about the corelation between the Ohm switch and how it affects the total wattage of this amp. Please have alook at the back of the VOX MV 50 head and you will see that same switch for 4, 8 and 16 Ohm. There is also written at the back: 4 Ohm = 50watt 8 Ohm = 25watt 16 Ohm = 12,5watt It seems that this switch regulates how much watts there will be depending on the LOAD of speaker! This makes sense. If so then at Pentode and 4 Ohms (with 4 ohm speaker) this Bugera V55 would give full on 55 Watts! On Pentode switched to 8 Ohms (with 8Ohm speaker) it must give less than 55 watts! Otherwise it just makes no sense if they are to overload the 4 Ohm position with an 4 ohm speaker!? I give up
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DefJef
THBC Moderator
Due to musical differences I've decided I can't work with myself any more.
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Post by DefJef on Mar 14, 2019 13:11:30 GMT
This is why you need to balance the LOAD of the speaker with the amp's switch, rather than just fiddling with that switch alone. It is not there for us to arbitrarily change the power wattage of the amp. It is there to allow the amp to deliver its optimum 55 watts to a wide range of speakers. A little luxury that we now can rather take for granted...along with non biasing Infinium technology. Old vintage amps never used to give us such flexibility. A Fender Bassman head simply wanted the correctly rated 8 ohms of speaker resistance or you could suffer the consequences. You could attach a higher resistance one for lower volume but it would be pretty foolish to attach 4 ohms and expect to crank it up. So yes, at pentode and 4 ohms and with a 4 ohm speaker the Bugera will deliver 55 watts just as it will also deliver 55 watts to an 8 ohm speaker when switched to 8 ohms. It's only when you mismatch speaker loads and amp resistance that you will get the doubling or halving of wattage and some rather unpredictable results. As regards the Vox MV50, it is a hybrid amp with only a 'kinda' tube in the preamp and no tube in the power stage. From the pics that I can find it is like those amps of old and has no speaker load switch, just some words: So, with this amp, it has been designed for its optimum 50 watt performance to be with a 4 ohm speaker. It has no switchable resistance. They seem to be just indicating this to the user by saying that anything else will result in lower wattage, which would be correct: resistance goes up, wattage goes down. The fact that wattage goes down could be a useful creative thing as it would mean you would need to crank it more to get an equivalent volume to the same amp using a lower resistance speaker, effectively giving you a small AC10 sort of thing with a 16 ohm speaker or a cleaner, greater headroom AC50 sort of amp with a 4 ohm one. However, as this is a solid state power stage amp we can assume these are more like solid state volumes - a whole lot quieter than even an AC10!
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Post by Deleted on Mar 14, 2019 15:39:25 GMT
Follow this link to Thomann and look at the back of this MV50 Butique (AC as well) head it HAS the switch for 4, 8 and 16 Ohms LINKOk so my safest way is to use the Triode to lower the wattage and play safe with my new 8 Ohms 50 watt speaker!
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Post by Deleted on Mar 14, 2019 16:22:40 GMT
Ah yes the un-nice distortion I already have with my Bugera V55 ... hm ... maybe due to the Bugera Speaker (not Turbosound). Very excited to hear if there will be some difference and if it will make me smile or else (Im highly trained in returning stuff back to Thomann)
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Post by Deleted on Mar 14, 2019 16:24:28 GMT
BTW, just noticed my two 6L6 power tubes not glowing the same; both have the red glowing points on top and ends but only one has that violet haze. Wonder why that is ... hm ... I still have the old ones which work.
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3,968 posts
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Post by salteedog on Mar 14, 2019 22:04:07 GMT
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3,968 posts
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Post by salteedog on Mar 14, 2019 22:17:56 GMT
Yup. I just checked the MV50 manual. The 'impedance' switch is just a subtle EQ.
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