300B / 845 SET amplifier

[Filterlab]

As my love for valves and Class-A continues, I find myself drawn to trying an SET power amp, or ideally monoblocks. I would never get rid of my current buffer and amp of course, but it's nice to chop components around for fun. My speakers are very sensitive so low power is not a problem.

I read great things about the 300B and 845 based power amplifiers, so tell me about your experiences.

[Opti-cal]

SET's are, for me, as intimate a musical experience that I've found so far. With efficient (usually horn loaded) speakers they convey music like no other configuration. I started, like many, with some cheap offerings from China (EL34 based amp) but I have to say even they were impressive. I got lucky and paired them with some Loth X BS1 speakers (which I own to this day) and the combination was instantly spellbinding.

I was given some very good advice regarding tube upgrades which made things even better. Also having a fully tube rectified power supply made a big difference for me. Transformer quality also plays a vital role (as ever) and if you can stretch hand wired point to point retains the purity of signal which is their trump card.

Some, especially the cheaper ones, can fall apart with more complicated passages of music and they do tend to flatter acoustic/jazz/vocals but I've managed to get them to sound lively with all genres partnering them with subs for a full range performance.

I've actually got a very high spec 300b being customised at the moment (300b for me is where it's at but 2A3 is awesome too, just a different "flavour", not tried an 845) I literally cannot wait to get it back.

I think at some point everyone should try a SET. I can see how they might not be to everyone's taste but if you favour engrossing musicality over sheer dynamics and scale it's a glorious experience when partnered correctly.

Go for it!

[Pigmy Pony]

My Audion Silver Night 300b Stereo power amp is currently enjoying a holiday from my system - pity you don't live nearer, you'd be welcome to borrow it.

It does a lot of things well - I like the sense of 'air' around the vocals, and on simpler material it is wonderful. Just seems to get a bit flustered with anything loud or busy. I'm currently using my Musical Fidelity A5 integrated, and my speakers, though sensitive, are liking the extra clout. I'll keep using it through the summer then swap back, and maybe decide what to stick with. Though really I'm so cloth eared I'd be happy with either

[Clive]

I've used 300B SE, EL34 PP, EL84 PP & SE, KT88,2A3, class D, solidstate class A/B solidstate class A SE. In my view the quality of results come down the power amp/speaker pairing. My 100db sensitivity OBs which are supported by active bass below 100Hz are ideal for low-powered amps. I always end up returning to my 300B amps with these speakers. In another system with easy to drive speakers but with 86db sensitivity - I use class D clarity to "wake them up". Most amps can shine but often only with speakers which gel with them. I echo the earlier comment about 2A3.

[Filterlab]

So, some positive things there! I have seen the ANK Legend monoblocks which I quite fancy building, but for the cash I'd rather get something ready-built. What sort of thing around the used £4K mark would be worth pursuing?

[Ali Tait]

300b are difficult to drive properly, it's not until you hear an amp that does so that you realise what's missing from most others. If I was looking for a 300b amp I'd be asking Nick Gorham to build me one.

[Opti-cal]

Ali is right, no point in messing about with inferior incarnations. C3M driver tubes seem to be a very good match with them, although I'd like to hear what a C3G could do (superior version of C3M).

You shouldn't struggle for that budget at all though. If you do go a tube rectified power supply route I can thoroughly recommend getting either a NOS RCA 5U4G or Svetlana Winged 'C' rectifier, they just sound better with the right amount of 'sag' for some very special tube moments. Also could shoot for a GZ34/5AR4 rectifier taking into account that the 5U4G is directly heated (no cathode) and the GZ34 is indirectly heated (cathode). (Something for your builder should you go that route). NOS Mullard/Philips would see you right in this department.

Output tubes would always be Gold Lion PX300B for me. They are about the best of the "less than a house deposit" 300B's. Although I like the EH 300B's too. (I think they are from the same factory and the Gold Lion's are 'selected'). Of course if you're feeling flush there are options to drop over half that budget on just a pair of output tubes, but I really cannot give any advice on doing so as I've never heard them, (probably a good thing).

[Macca]

300b are difficult to drive properly, it's not until you hear an amp that does so that you realise what's missing from most others. If I was looking for a 300b amp I'd be asking Nick Gorham to build me one.

Yes. That one he built for Gaz was the only 300B I've heard that lived up to the hype.

[Ali Tait]

Yes agreed, best 300b I've heard yet.

[JohnJo]

And it looked awesome!