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PostPosted: October 21st, 2015, 4:41 pm 
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Joined: October 21st, 2013, 6:53 pm
Posts: 270
Changing voltage: tube amp
I know the other thread went in some weird directions so I started a new one.

The message from the other one is that a capacitor, inductor, or a resistor placed before or after my output transformers would not change the voltage going to my speakers, but what about another transformer?

I seem to be convinced that a little change in voltage into my speakers might change the characteristic sound of the speakers. Specifically, I think an increase in voltage is going to sound better!

I would like to place a transformer in between the outputs of my amplifier and my speakers, but locating a transformer that won't damage my amplifier, or burn itself out because it is too small seems to be a little challenging.

Does anybody have any suggestions how to find a transformer to do what I'm talking about, or have some practical reason to talk me out of it?

Thanks,

Chris


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PostPosted: October 21st, 2015, 4:57 pm 
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Hey Chris,

Here is the deal: Power (P) = Voltage (E) x Current (I).
Current (I) = Voltage (E) divided by Resistance (R).
Substituting voltage divided by resistance in the power equation, we get:
Power (P) = (E) x (E) / (R) or P = E squared/R

Since R = your speakers' impedance, say 8 ohms, it is fixed.

So, to increase voltage, will increase power. In other words, to increase voltage, turn up the volume control!

Hope this makes sense.

Stuart


BTW, thanks for your hospitality! Your room looks great, the speakers awesome and you have a very nice equipment rack.

Now treat that room! Leave the speakers alone until your room is up to the task! Seriously, you'll be very happy with the results!


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PostPosted: October 21st, 2015, 6:40 pm 
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Joined: March 2nd, 2013, 2:43 pm
Posts: 157
Location: Potomac, MD
Chris,

You need to know if your amp is running out of power and clipping. If it is, then you need a more powerful amp. Adding a transformer in line with the speaker will not give you more power, which is partially reflected in the voltage that your amp delivers to the speaker. But equally important is the current that the amp delivers to the speaker. Adding a voltage step-up transformer to give you more voltage reduces the available current, and if your amp can't deliver the current the voltage will collapse anyway. If you have a tube amp with output impedance taps, you can increase the voltage at the expense of current by using the 16-ohm tap if it has one. Using the 4-ohm tap increases the available current at the expense of voltage. Perhaps more important, using the 4-ohm tap raises the damping factor (tighter bass) while the 16-ohm tap reduces damping for a more resonant sound.

Nothing beats an oscilloscope for determining for sure if your amp is clipping.

David Berning


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PostPosted: October 21st, 2015, 9:06 pm 
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Joined: October 21st, 2013, 6:53 pm
Posts: 270
Yeah, Yeah, I know. I'm just throwing out crazy ideas at this point.

It's just that I have exhausted all my ideas as far as developing my speakers at this point, and I seem to think the missing ingredient is somewhere in my amplification stage.

I'm not looking for more power(SPL). I'm looking for more intensity.


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PostPosted: October 21st, 2015, 9:13 pm 
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Now treat that room! Leave the speakers alone until your room is up to the task! Seriously, you'll be very happy with the results![/quote]

I'm just not sure what I can get away with in the room, and with the exception of the curtains i'm pretty happy with the way it is. Also, I developed all seven generations of speakers in the room as it is, so I'm a little bit afraid to change the room at this point :confusion-confused:


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PostPosted: October 22nd, 2015, 9:28 am 
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Joined: February 28th, 2013, 10:38 am
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chris1973 wrote:
I seem to think the missing ingredient is somewhere in my amplification stage.


Perhaps you should schedule a meetup at your place and encourage people to bring their amps so you can confirm/deny your theory ;)

Roscoe


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PostPosted: October 22nd, 2015, 12:07 pm 
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Joined: March 12th, 2013, 1:49 pm
Posts: 205
I believe you would be best served by taking the beginners radio course at the NCRTV in Bowie, which I believe a number of the members have taken. Your understanding of electronics needs a big upgrade, this will be a big help in figuring out what it is you hope to accomplish. As it is, your looking for a black cat in a dark room where there is no cat! Not trying to be a jerk here, but for what you are trying to accomplish you need at least a basic understanding of electronics...


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PostPosted: October 22nd, 2015, 12:20 pm 
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Joined: October 21st, 2013, 6:53 pm
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randy warren wrote:
I believe you would be best served by taking the beginners radio course at the NCRTV in Bowie, which I believe a number of the members have taken. Your understanding of electronics needs a big upgrade, this will be a big help in figuring out what it is you hope to accomplish. As it is, your looking for a black cat in a dark room where there is no cat! Not trying to be a jerk here, but for what you are trying to accomplish you need at least a basic understanding of electronics...


No, you are absolutely right Randy,

I have spent all my time fooling around with speakers and cabinets (stuff you only need to have a couple formulas figured out to do), and I know almost nothing about the equipment I use to drive them!

Roscoe gave me a good link to some Navy electrical training info, and Stuart brought me a couple of books. I'm not sure I want to take a whole course. Do you have any recommendations for online sources or books?


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PostPosted: October 22nd, 2015, 12:32 pm 
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Oh yeah,

My whole life is about looking for black cats in dark rooms!


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PostPosted: October 22nd, 2015, 1:48 pm 
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chris1973 wrote:
Oh yeah,

My whole life is about looking for black cats in dark rooms!


All you need is a little tuna, they'll find you ;)

Roscoe


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