Theta Prometheus Monoblock vs Bryston 7BSST2


I was all set to buy the Bryston 7B-SST2 amps to mate to a KEF Blade (or Blade2). However, the recent review of the Theta Prometheus on Stereophile has me intrigued. I like the benefits mentioned for the class D amps over AB or A. Less power consumption, run cool, small footprint.

I heard these amps at THE NEWPORT SHOW this year and they sounded very good but I cannot really tell in a show (unless it is really bad sound). I know how the Bryston sounds and like the fact that I would have a great RELIABLE amp if I went with Bryston. My pre-amp in the SS BAT VK-42SE. I will have a 2 channel computer based system, with the PS Audio DS DAC.

Anybody using these new Theta amps care to provide feedback on your experience. I would prefer to hide any new amps in a closed audio rack because of potential damage (spills etc..)
yyzsantabarbara
YYZ, I have owned the Veritas since it was first introduced. Below are some thoughts and suggestions.

1) I have demoed many amps in and out of my system. IMHO the Veritas punches way above its price point.

2) NO amp is perfect or ideal for everyone. We all hear a little differently and have different tastes.

3) I had Merrill Audio replace the fuses in my Veritas with the new Synergistic Research Red fuses. All I can say is DO IT!! I second thought, DO IT ON ALL YOUR EQUIPMENT.
I have tried many fuses and while a few made a slight improvement (many did not) the RED fuse is amazing for just a fuse. While you must have the fuses in the Veritas replaced by the factory any fuses that are DIY can take advantage to the 30 day free trial that Synergistic offers.

4) I owned the Bryston 14B SST2 amp. It is the stereo version of the 7B SST2 mono that you mention above. Only difference is one case vs two.
it is a really nice amp and sounds good.
But IMHO the Veritas sounds better.

5) I agree with Guido. Just because an amp uses either a SMPS or a linear power supply does not dictate how well it will sound.

6) Whatever amp you get I would highly recommend that you use Stillpoint footers. And if you can afford it get the Ultra SS. The Ultra Mini is worthwhile but the Ultra SS is better. You can use three vs four in most cases.
And if your budget allows use the Ultra SS on your speakers. Depending on your budget Use the Ultra Mini on your amp/s and the Ultra SS on your speakers. Even if your speakers use spikes.

Regardless what amp you get I wish you good luck and happy listening.

PS Hey Guido. I hope all is well.

Hey Al, things are good.... Absolutely adore my big rig with Rowland Aeris DAC and M925 monos....

Yet, at its uber-attractive pricepoint, the little Taranis stereo with gain raised to 29dB was a real treat on my Vienna Die Muzik speakers.

For the rest, believe it or not... I am having immense fun fiddling with high brass instruments and mouthpieces.... Adams A4 Heavy trumpet, Kanstul 1525 copper flugelhorn, and very recently Carolbrass CCR-7772R 3-crooks Bb cornet and CCR-7775 Eb soprano cornet... Nuts am I? For sure!

G.
Not that it makes much difference to this discussion but the Bryston 14B amp is not 2 x 7B in one chassis. They differ in capacitance as the 14B has 108,000MFD per channel and each 7B has 160,000MFD so the 7B amps offer 48% more capacitance in each channel....
Rgd, that may be but the owner of Bryston himself told me what I wrote in the above post. So ...

"George, which amps have you experienced which are the audible cause of your pessimism?"

Many and they all have the same trait, explained below.

Until the future technology gives us higher switching frequency, we'll get this (linked) switching frequency noise on the top of the square wave in pic 2 and that's at 1khz!!!
At 10khz (not shown) it's 10 x worse (if this was a linear amp, you'd say it was broken)
And the output filter is already started to roll the audio frequency off at 10khz to try to minimize it Pic 1.

http://www.stereophile.com/content/theta-digital-prometheus-monoblock-power-amplifier-measurements#d5BMlUSvHXmmeEbA.97

Today we have two detrimental ways to get rid of the Class D switching noise, with output filters on these amps.

1: The filter to roll off earlier into the audio band to minimise the noise, result (soft/opaque/dark treble and upper mids and hf phase shifts)

2: The filter to roll off later with no treble roll off and minimized hf phase shift, but let 10 x the switching noise through (hard in your face treble and upper mids).

Or we bite the bullet and use Class D just for bass, and wait for technology to advance to get much high switching frequencies for class D so we can then filter them out much higher and more aggressively with being near the audio band.
It will happen one day and that's when I will get one as well, but today it is just not ready yet, it's still developing, when it does our heavy massive linear amps will become boat good anchors.

Cheers George