AVA Ultravalve, TAS Product of the Year 2010 Award!

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Lefty052347

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Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #80 on: 3 May 2016, 10:22 pm »
I have had my Ultravalve for 6 years and I can personally attest that it mates well both solid state and tube AVA preamps.  I don't know any amp that mates with the Songtowers any better than the Ultravalve. 

If you decide to get one I recommend trying both the 4 ohm and 8 ohm taps to see which gives you the best match.  My somewhat limited experience with Songtowers suggest the 4 ohm taps will work the best.

Regards,
Dean

Yomaha

Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #81 on: 5 May 2016, 05:32 pm »
Thanks for the feedback, Dean!

jk@home

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Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #82 on: 6 May 2016, 02:05 am »
Has anyone hear this amp driving a pair of KEF LS50s? Mine are fairly nearfield (6-7' from the chair) in a 12 x 15 room. I know the KEFs drop slightly under 4 ohms in the upper bass region. A problem?

tomatchison

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Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #83 on: 7 May 2016, 11:11 pm »
I, too, would be very interested in the answer to this question.  I'm using an AVA tube preamp and Synergy SS amp right now with my LS50's, and that's sounding pretty darn good.  But I'm imagining a pure tube power amp would sound even better.

avahifi

Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #84 on: 8 May 2016, 05:27 pm »
The Ultravalve should work great with your KEF LS50 speakers.

Use the four ohm taps.

My Ultravalve is wonderful driving either my Janszen electrostatics or Phllharmonic 3 speakers, both about 84 db 4 ohm loads.  The combo is not going to break windows, but at rational listening levels, the music is just engaging and spellbinding.

Frank

flash7725

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Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #85 on: 11 Jan 2017, 04:09 am »
Does anyone have any experience using a passive preamp with an Ultravalve? The passive I built has a 50k ohm potentiometer. I'm happy to build one with a different value if that's what's needed to mate with an Ultravalve.  Thank you.

avahifi

Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #86 on: 12 Jan 2017, 07:57 pm »
The Ultravalve has a high (470K ohm) impedance so it won't load down your passive volume control.

However, its voltage gain is 15 (about 23 dB) while most solid state power amps are in the 25V (28 dB) range.

This means you will need to turn the volume control higher for equal sonic output from the Ultravalve.  The Ultravalve swings about plus and minus 24V peak.  Thus you need 24 divided by 15 = 1.6 volt peak from your volume control to drive the Ultravalve to full power.

If you are using the equipment in a larger room with relatively inefficient speakers (86 dB or less) then you probably won't be able to play loud enough with the Ultravalve, especially if the output voltage level from your music sources is also on the low side.  This is not a power issue, just voltage gain.

This is where an outstanding active preamp such as our T10RB vacuum tube preamp or Vision SL solid state preamp (bass price on both is $899) would be very useful.

Frank

avahifi

Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #87 on: 12 Jan 2017, 08:05 pm »
By the way, the Ultravalve received another Editors Choice award from The Absolute Sound for 2017, along with the Fet Valve CF tube preamp, the Fet Valve 600R hybrid tube power amp, and the Vision solid state phono preamplifier.  It is still very hard to beat AVA products overall.
Frank

flash7725

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Re: AVA Ultravalve, TAS Product of the Year 2010 Award!
« Reply #88 on: 13 Jan 2017, 06:25 pm »
Great to hear that about the passive preamp impedance matching. Thank you, Frank. My Theta DAC has an 8 db gain over a typical DAC, so the volume shouldn't be a problem at all. In my experience, an impedance mismatch with a passive preamp can rob a lot more than just volume, although it might be a little hard to quantify the difference. Either way, this should be great to hear! Thank you again.