How is the Shiva 90 watts?

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richedie

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I know I just don't understand. Can someone explain how the 20th Shiva is 90 watts if it has two tubes? And how would it be different if it had 4 power tubes like most 100 watt heads? More plate current? Fatter sounidng?
 
KT88's put out more power per tube. Like every tube they have their own sound. Some have used 6550's for a different tone but still with same power.
 
RG955TT":3b9rwh4t said:
KT88's put out more power per tube. Like every tube they have their own sound. Some have used 6550's for a different tone but still with same power.
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My 20th Shiva has EL34s and the amp is rated at 85 watts with the EL34. How so?
 
Maximum wattage is dependent on each amp circuit. Many manufacturer lie or justkey the consumer assume.

Some o from Steve fryette focusing on his amps mostly.



Check it out:
For a good margin of safety, peak power can be considered 2 times RMS. That's a very crude generalization, but accepted as typical by the industry.

Speaker peak handling capacity must also be generalized at 2 times RMS because of the many factors used to determine hard figures.

The typically accepted rule of thumb for safety is 2 X Speaker RMS to 1 X amp RMS, or in this case, 120 speaker watts to 60 amp watts.

VHT amplifier and speaker power ratings are conservative (what we publish is equal to or greater than actual based on generally accepted test parameters - see below).

So normally you'll be OK with a 2X12 P50 cab and a D60. However, speaker rating goes down in an open back cab. But as long as you are not slamming the amp, you should be OK.

Using the amplifiers published model power category as a power rating can be misleading. Same goes for speakers.

Many amp companies do not rate their amps based on actual power performance. Instead they just let the consumer assume that 2 tubes = 50W, 4 = 100W, etc. If pressed some would have to admit their power ratings are based on distortion figures as high as 20% or more, which would translate to ratings that are 20 - 40% greater than RMS at onset of clipping. Hey, you want distortion anyway, right?

Some examples:

D60
Published - 60 Watts
Actual - 62 Watts RMS

D120
Published - 120 Watts
Actual - 118 Watts RMS

50/CL
Published - 50 Watts
Actual - 50 Watts RMS

2/90/2
Published - 90 Watts/Channel
Actual - 105 Watts RMS/Channel

2/50/2
Published - 50 Watts/Channel
Actual - 62 Watts RMS/Channel

5150/6505
Published - 120 Watts
Actual - 72 Watts RMS ----------->:eek:

Dual Rec
Published - 100 Watts
Actual - 72 Watts RMS

Triple Rec
Published - 150 Watts
Actual - 108 Watts RMS

2:90
Published - 90 Watts/Channel
Actual - 65 Watts RMS/Channel

TSL100
Published - 100 Watts
Actual - 78 Watts RMS
 
I personally do not see it being possible to get 85 watts out of 2 EL34's. I bias all of my amps with a compubias which gives power output and an EL34 is a 25 watt tube at full output so.....do the math, no way are you getting 42.5 watts out of an EL34. Just sayin...
 
It's not 80, it's 80, per Bogner.

I don't know the exact science of what's going on, but I will say that the (2) EL34 Shiva sounds and feels a LOT closer to a 100W head than a 50W. You can tell that it has more juice than a regular 50 watter.
 
richedie":2gzk45g2 said:
RG955TT":2gzk45g2 said:
KT88's put out more power per tube. Like every tube they have their own sound. Some have used 6550's for a different tone but still with same power.
Click to expand...

My 20th Shiva has EL34s and the amp is rated at 85 watts with the EL34. How so?
Click to expand...

Max plate dissipation does not equal max output power. You can easily pull 100w out of a pair of EL34s.
 
Higher plate voltage probably has something to do with it.

All I know is my old Shiva was one of the loudest "2 powertube" amps I ever owned. :rock:
 
wattage isnt just based on the tubes, transformers, voltage ,etc. factor in as well. I have owned 2xel34 amps that were 25 watts total so it can go either way .
 
I always thought tubes have a max output design parameter. Of course you can go lower in power (just underbias and you can see that) but even with over biasing and such don't you just hit a wall with total max power a specific tube type can put out? Otherwise why wouldn't every 100 watt EL34 amp just have 2 tubes to keep cost down etc. And there wouldn't be a need for 6550's and kt88's and other high output tubes?
 
My old EL34 Shiva was WAY louder and had a lot more headroom than my Traynor YCS100H 4XEL34 head. Dunno what the science is, but the volume and feel were pretty apparent.
 
The 20th Shiva was designed for 2-KT88's. At 45 watts output, this is 90 watts. These are nominal figures, not actual. That would be sort of silly as every amp would be different.

4 x EL34's = 100 watt nominal. At one point, there were some EL34's published as 30 watts. I believe this was the old Tesla tubes. The original Ubershcall was listed as 120 watts, which is where this came from. The screen/grid was build to handle it though.
 
steve_k":w911zqri said:
The 20th Shiva was designed for 2-KT88's. At 45 watts output, this is 90 watts. These are nominal figures, not actual. That would be sort of silly as every amp would be different.

4 x EL34's = 100 watt nominal. At one point, there were some EL34's published as 30 watts. I believe this was the old Tesla tubes. The original Ubershcall was listed as 120 watts, which is where this came from. The screen/grid was build to handle it though.
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All true... but I know that the 2XEL34 Shiva I had was supposedly 80 watts. Nominally, I would think it'd be 50 watts. At any rate, it seemed to put-out a LOT more volume and headroom than my 100 watt, 4XEL34 head.

My 4XEL34 XTC Classic supposedly puts-out 120 watts. Reinhold seems to like to push his EL34s beyond the standard 50/100 specs... no?
 
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