Hi Tony,
I've had experience with both my WA5 (upgrade parts and tubes), WA234 (both with stock and my tubes) as well as a breif listen to a BHSE, SR009 combo.
Comparing the stock 234 with my maxed 5, the main improvements were mainly just a widening of the soundstage and more precision with imaging. Background noise, which I thought was already low on the 5, was now completely gone. The dynamics were noticeably better, loud passages shook your ears and silent passages had an inky deep blackness to them. The improvement was enough for me to concider the upgrade after only a quick 10 minute listen, if I had to quantify it I'd say about 10%. It may not seem like much but it was as much of a jump as going from stock tubes on the WA5 to a full upgrade complement or going from the GS-X to the WA5.
If you've heard the WA5, it's tonality and wide enveloping soundstage carry over seamlessly to the 234. With the WA5 I would switch between either the KR300B's or Royal Princess tubes depending on if I wanted more speed or more lushness. With the 234 the KR's retained all their speed but weren't dry in the mids it was as full and lush as the princesses were in the WA5.
Going in to audition the 234 with my tubes over stock sealed the coffin on the WA5. The WA5 improves a lot with tube upgrades but you still get the characteristics of the amp imposed on the tubes. With the 234 tube rolling can be summed up with a single word 'transparent'. You hear each change the tubes bring to the amp, I spent most of the time listening to the 234 with KR300b balloons, syl bad boys and full music 274b/+/n rectifiers. The amp was on high plate output. Driving the abyss on high plate was an easy task, the volume dial never made it past 10 o'clock and it only made it past 9 on very quiet pieces. Going from the stock tubes on the WA5 to better ones is a big leap, putting that same tube complement in the WA234 takes the tubes to a whole other level. With the Above tubes in the WA5 I really enjoyed the pacing, bass weight and immediacy of the sound. I thought that was the pinnacle. Switching to the 234 it showed what it was compromising, it had all the speed, weight and immediacy that was there in the 5. But it bought just an organic sense of musicality to it, with the 234 you get spade loads of detail over the 5, but that's not what you end up listening to. It's still so musical and involving that you get lost in the music as a whole. Sure you can still go into it and focus on the details but getting lost and enjoying it is soo much easier.
Another thing that is apparent is how revealing if other components the 234 is, I know the cable debate is a touchy subject, but going between one of the new cables they had to test at A2A, cardas clear light and cardas clear interconnects. The differences became readily apparent, tonality and sibilants being the main points the 234 would reveal between cables. I actually was hoping there wouldn't be a difference between the clear and clear light since they're essentially the same apart from the air tubes in the clear. But it was ever so less sibilant and the tonality was fuller and warmer, easier to get lost in and enjoy.
Comparing the SR009, BHSE and Abyss, 234 combo. The SR009 does everything right... But only on a technical note, comparatively it's very mechanical and it looses it's sense of involvment and enjoyment. That organic sound just isn't there, you listen to the music as each individual part instead of a cohesive whole. That's just not the type if listening I enjoy, so my views on it may be bias.
Just to add in purchasing the 234 was not easy financially for me, still being an apprentice, having a mortgage and planning a decent sized trip along with all the other associated costs with the WA234. I had to prioritise my spending to afford it, it wasn't just walk in, drop cash and walk out. Making the decision however was that easy, for me the improvements were worth every cent. I just had to find a way to gather the funds.
I will note I haven't listened to either the 234 or WA5 in about 2-3 weeks so it's all from mort at this point so I may be romanticising it a bit. But if you have any specific questions I'll do my best to answer them
