2. amps-preamps
  3. 123296-8622

Will Changing my 100 Watt Tube Amp to a 200 Watt SS Amp Solve My Problem?

Hello All,  I have a 100 watt Audio Research VT100 mk II amp, with an Audio Research LS-25 preamp.  My speakers are relatively low in sensitivity, and I find that I must turn the volume up to 3 o'clock on the preamp to get enough volume for a loud listening experience.  When I do that, I am introducing more background noise.

I would like to achieve a quieter noise floor.  I am also curious about the limits of the 100 wpc amp with the Mira Monitors.  Would an older Krell 200 watt class A amp "control" the speakers better?  If so, what are the benefits of this?  There are a few amps on this site that caught my eye, all about the same value as my amp, so I can potentially make a move with very little cost.  Is this a good idea? How much wattage increase is necessary to get a significant enough difference?  Would a jump to 150 watt solid state be sufficient?


here are the 3 amps that caught my eye:

Ayre: https://www.audiogon.com/listings/solid-state-ayre-acoustics-v-5xe-amplifier-2016-02-05-amplifiers-h...

Krell: https://www.audiogon.com/listings/solid-state-krell-ksa-250-2016-02-14-amplifiers-91754-monterey-par...

BAT:
https://www.audiogon.com/listings/solid-state-balanced-audio-technology-bat-vk-250se-bat-pak-2channe...



You can see my complete system here if you want to know more about the other components:  https://systems.audiogon.com/systems/5421



Thanks!
Mark
marktomaras
rhljazz
1,255 posts
 

The answer is no related to your specific complaint.  The input sensitivity of your current amp is 1.9V required to drive at full power.  The Krell KSA 250 requires even more voltage at 2.3V for full output. 

One of my amps is a VAC Pa100 which only needs .775V for full output.  So, to address your complaint of needing to crank the volume control way up which may reveal the inherent noise of the preamp, you should look for an amp which requires less voltage to achieve full power.  Tube vs solid state has nothing to do with your complaint. 

However, tubes will always be happiest driving a speaker with higher impedance.  I am unaware of how your speakers perform regarding impedance.  

almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
Hi Mark,

If the noise only occurs when the volume control is turned up to a relatively high setting, it means that the noise is being introduced into the signal path "ahead of" ("upstream of") the volume control. A more powerful amp will often (although certainly not always) provide higher gain (the relation between its output voltage and its input voltage), which would cause you to utilize the volume control at lower settings. However the resulting noise level would be no different, since the amp is "downstream" of the volume control.

Unless, that is, the noise is being coupled into the upstream part of the signal path BY the power amp. But as I recall you’ve probably addressed that possibility already, by physically relocating the components in your setup.

Regards,
-- Al

ahendler
416 posts
 
I don't think your issue is power but sensitivity. Sensitivity in a power amp means how much power out do you get for a number of volts in from the preamp. You need either a preamp with more voltage output or a power amp with higher input sensitivity. Doubling the power will not solve your gain problem
Alan
czarivey
5,946 posts
 
if you don't have enough phono gain no larger amp will help.
either higher output cartridge or higher gain phonostage will cure your problem.
atmasphere's avatar
atmasphere
11,846 posts
 
This is not a power amplifier issue!

This is a noise problem in the preamp. Ahendler got it right.
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