Willsenton R8 gets muddy When Too Much Sub Bass is Present

There is a  Willsenton R8 used with a Cabinet Horn Speaker Design by a member of my local HiFi Group.

The Amp' has been questioned by the owner for an excess of low end Bloom. As a result the Amp' was made available to be used as a Demo', through being auditioned by the HiFi Group in another Valve Amp based system known for having a transparency in relation to a Valve Amp Set Up.

The R8 during the Demo', was detected for its capability to Bloom, Bloat the Lower Frequencies produced by ESL Speakers, there was certainly no defined cut off for a Bass Note. The usual ancillaries were on standby and a method proposed to tidy things up was for mounting the R8 on a Stacked Panzerholz Sub-Plinth with AT 616 Footers as separators between Sub-Plinths. With this mounting method in use with the Amp, there was a notable change, such as, Tidying Up the bottom end frequencies, a Bass Note Cut Off, had a edge, even though smeared. The change was also noticeable to the point, the Mid's and Upper Frequencies were projected and approaching being a more coherent presentation across the frequency range.

One of the Groups Valve Guru's was confident a Valve Roll at this stage would transform the Amp to be much more coherent and attractive. 

In my evaluation, for my particular taste, I am Bass Sensitive and can find it it to become fatiguing when Bass has a noticeable presence. The presentation improved in attraction, when different mounting for the Amp' was used, but for me, much more was needed to improve the overall coherence of the frequency range. 

The R8 owner has made it known, they have now adopted 'methods discovered' to work with the Amp's circuit (Tube Choices) and has been using a Sub-Plinth with Gaia Footers.  Their assessment is that this has substantially improved the presentation over the one listened to at the Group evaluation. I know this persons experience and feel confident they have found a level of improvement that will further impress, when next demo'd.

@pindac: This is interesting! I had no idea that isolating the R8 from vibration would have such a noticeable effect on it's sound. I agree with you regarding bass. Ironically I built an 18 inch sealed subwoofer that is part of the 2.1 setup with the Heresys. My thought was that if the sub was large enough it would need to move very little to produce sound and that would keep the distortion low. After having placing it in the living room for about a year I believe that to be true. Prior to that I had built a sealed 12 that would hit points of distortion trying to keep up with certain tracks. The sub is adjusted to the point that it is unnoticeable even at high volumes, and it has a very wide sweet spot. The R8 is near it, placed on a veneered MDF stand, where it likely is subject to vibration. For my record player I built a butcher block isolation platform with spike feet and it has helped to dramatically reduce vibration. Maybe it's time to build another one for the R8 and move it further away from the sub... Do you have any recommendation regarding which tubes to replace the stock ones with?

My experience with Valve Equipment is that all devices can have their produced sonic changed when mounted on a Isolation Platform.

The Material for the Platform and Footer chosen will also create the perception that the sonic is reinforced in attraction of detraction. In general on a standard mounting platform there is added attraction to be found if trialing a few different mounting configurations.

As for the owner  of the R8 referenced, the following is their words following the Group Demo' referred to:

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I mentioned that I'd ordered a set of China HiFi's recommended Psvane  CV181-T MkII valves, to replace the 6SN7s in the Willsenton R8. Earlier experimentation with new 'Tung Sol' valves was a grave disappointment, but these Psvane tubes are different.

When you heard the amp at John's, with stock NOS Russian tubes, it sounded good, and probably better than its modest price might have suggested.  Here, I could not quite decide between 'Triode' and 'Ultralinear' operation - the former sounded a bit weak, and the latter a bit too 'boosted' in the manner of a loudness control.  I was aware that neither were optimal and the SuperNait3 was better all round.

Anyway, with the new Psvane tubes fitted, there is immediately more colour, air, textures etc - all the audiophile gushing stuff that says 'a really nice, musical sound'.  Now, triode mode has a beautiful warm but detailed sound character with real grace and air; and there is now no need to go for ultralinear at all for extra tonal colour.  The Willsenton amp is quite literally transformed into something that is not just 'rather good' but actually 'stunning'.  I am pleased.

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Interesting to see the difference given as a description about the impression made during the Demo', as in all Audio situations each individual are with their own sensitivities to produced sound and have their own unique preferences for the sonic to be lived with.

There are other Upgrades to be found through a typical Web search, but the following link is showing a circuit Mod' that is one worthwhile learning about.