SET Asylum: REVIEW: Wright Sound Company MONO8 MONO BLOCK Amplifier (Tube) by Willie The Squid Single Ended Triodes (SETs), the ultimate tube lovers dream.

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Hello Fellow Inmates:

This is a review of the recently updated version of Wright Sound Company’s Mono 8’s – 300B monoblock amplifiers.

As many of you know from my posts, I’ve owned a pair of the Wright WPA 3.5 (2a3 output tubes) monoblocks for nearly 18 months. They drive a pair of Reference 3a Royal Master Control loudspeakers full range. This speaker is a two-way with no crossover (just a cap to filter the tweeter), is effectively 90 db a 1 meter, and has a flattish impedance that does not fall below 6 ohms. The speaker is a fairly easy load and matches well with single ended amps. I also supplement the Royal Masters with an 15 year old self-powered AudioPro subwoofer which rolls off at 12db / octave beginning at 40 hz.

George Wright asked me to listen to his recently updated Mono 8s in my home system. I did not ever hear the earlier version. I have had possession of these amps for approximately one month. First I’ll identify the changes made by George Wright from the earlier version of the amps – then on to my listening impressions.

The Mono 8 has been recreated to boost it's output and improve it linearity. Wright removed both the 6SN7 and the 6EM7 and replaced them with a 6DN7 dissimilar dual triode. The first section, used as a voltage amp, is similar to ½ of the 6SN7; the driver section is similar to ½ of a 6BX7. The 6DN7 is a rugged, versatile tube built for long life operation. In televisions it had to cover the frequency range of 30Hz through 15,757Hz plus or minus 1/2dB. In Wright’s circuitry, it covers the entire audio spectrum. According to Wright, GE was the primary supplier of this tube so the tube is quite predictable in it's performance. Wright made this substitution because the 6DN7 (directly designed by GE for it's late 50's black and white vertical circuits) has certain advantages over the other tubes.

One advantage is that the driver can handle higher voltage swings with more drive power. Too, the drive section also operates at a lower plate impedance, very useful for driving a low mu triode of the 300B family. Finally, the driver is a plate output type and does increase gain, increasing the sensitivity to a more useable level.

The Wright Mono 8s come fitted with the JJ300B output tubes. Wright indicated that he finds it easier to balance out the AC hum from it's filament. The JJ300B is a great sounding 300B type tube for a reasonable price. Several years ago, during the time that I was using a pair of Cary 300B SE monoblocks, the JJ300B was the best balanced and most natural sounding 300B that I used. I never had an opportunity to try the WE 300B. I did have the chance to use KR 300Bs, Centron 300B, Sovtek 300B, and Chinese 300B.

Listen Up!! The Wright Sound Company Mono 8 is a truly great sounding amplifier! At $1,650 a pair, they are as much a steal as the Wright 3.5 monoblocks are at $1,300 a pair. There is a definite kinship in the design approach and the resulting sound as between the two amplifier types. But there would be no mistaking them.

First, the Mono 8s have considerably greater perceived power than the WPA 3.5s. In my system, the WPA 3.5 can almost rock and roll. The Mono 8s definitely rock and roll. (Remember, this is on 90 db efficient speakers.) This additional dynamic capacity might not be very important on highly efficient horn loudspeakers – but for “real world” dynamic loudspeakers that have some level of WAF, this increase in power is both welcome and climactic. The sense of ease and power displayed in the bottom end is just amazing for a 300B single ended amplifier. When I purchased my WPA 3.5 monoblocks with 3.5 watts RMS and 8 watts peak, they were a huge improvement over the Cary 300B SE monoblocks in terms of PRAT. And their perceived loudness was equivalent to the Cary amps. By the same token, the Mono 8s are a major step forward in their ability to control the speaker – both dynamically and in terms of rhythmic drive. Moreover, they have the ability to fill the room with a stunning sound matrix at much higher volume levels.

Second, the Mono 8s do not require a sub-woofer to supplement the bottom end with modestly efficient dynamic speakers than can go down to 50 hz (or better yet 40 hz) flat. I spent signifi-cant time with the sub-woofer both “in” and “out” of the system. I could certainly tell the differ-ence, but in a musical sense, the sub wasn’t necessary – the Mono 8s delivered the musical goods completely on their own. In contrast, in my system the WPA 3.5s do effectively require a sub-woofer. Without the sub-woofer, the 3.5s are a bit too “delicate” when I’m playing demanding sources – they run out of gas. What this means to me is: the Mono 8s offer much more flexibility for many systems where the purchaser doesn’t want the complexity or expense of adding a self-powered sub.

Third, fabulous midrange. This amp has the classic 300B sound down, in spades. Living with 2a3 amps this last 18 months I had almost forgotten…the 300B midrange is thoroughly “different”. It’s “bigger” and enormously seductive. Well recorded voices are just riveting. Ensemble work is so present. It’s almost like a “hyper-reality” of what was going on at the recording. Highly musical!

Fourth, the Mono 8’s have great extension, bottom to top. I spoke earlier of the energy of the bottom end. Here I’m relating the sense that the amp can go down as far as the source material will take it. This is more impression than fact – because clearly my system is not full range on the bottom without a sub-woofer. Suffice it to say that I got the “sense” that the speakers were running out of room well before the amp was running out of ability. Up top, the highs were shimmering and well extended.

Those are the exceptional qualities I found in the Mono 8s. No amp is perfect, however, and I noted the following conditions. First, the overall continuity of the Mono 8s was different than the WPA 3.5s. By continuity, what I refer to is the organic sense of wholeness that is emanating from the speakers, where all the parts fit together. In this sense, the Mono 8s are a slightly more “hi fi” sounding than I find in the WPA 3.5s. Whether this is a function of the amp or of the tube type (300B vs. 2a3) is an open question. Second, the Mono 8s were more demanding of good source material. If the source material was limited or compromised in some way, the Mono 8s were more revealing. If there were problems in the recording, there was no hiding them. For many, that would be an admirable trait.

That’s pretty much it. The Mono 8s have all the wonderful characteristics associated with a very high quality 300B single ended design and implementation. The Mono 8’s are rated at 8 watts per channel and can be driven into class A2 which gives them the dynamic abilities of a 16 watt per channel amp. With their high quality power supply, this means that on moderately efficient speakers they sound quite powerful – astonishingly dynamic for a single ended 300B amp.

This post is made possible by the generous support of people like you and our sponsors:

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