Been playing with valve amps

Dev

I second SCIDB. I used my Border Patrol [18 watts] with my old Sonus Fabers when I was waiting for the Living Voices to be delivered, and there was no problem at all in my normal-sized living room power-wise. Even if on paper an amp is low-powered, it'd be worth a go IMO.

Paul

Paul

 

Paul, I think you may be on to something here.

To continue the story, the Rogue Tempest did not arrive as promised. I'll try to find out why tomorrow. In the mean time I borrowed Ian's (Sideshowbob) Leak ST20. This power amp (which I'm using with a passive pre) only gives out about 10WPC but at normal listening volumes it sounded better than the WAD. I can't explain why. The WAD seems to have much more headroom and seems like it will go as loud as I could wish but the Leak was more "together". I went back to my MFs and despite the aforementioned low bass issues, I preferred both the WAD and Leak. Ouch!

I can't pick a clear winner out of the WAD and Leak. The WAD seems like it will go much louder (I haven't yet had the opportunity to test this due to neighbours and other members of the family) than the Leak, but the Leak seems less boomy (leaner perhaps?) in the bass. I think a more extended listening session is in order.

 

Hi Dev,

You can also add the Prima Luna Prologue Two to your list. This is an valve amp for £995 and is 40 watts per channel. It has had some very good reviews and sound interesting.

http://www.pistolmusic.co.uk/product_info.php?product_id=2


SCIDB

 

I reckon you're unlikely to find anything better than the Leak at its price point, different maybe, but not definitively better.* It's considered a classic for a very good reason. The WADs I've heard (which is most of them, at both a WADFest and bottleneck's bake-off a couple of years ago) don't give up much to more expensive commercial designs either, IME, until you get into territory well above your budget.

So, my advice would be to try a couple of modern and more powerful things at both the mid point and the top end of your budget, and forget the budget Chinese amps, which are no doubt fine, but I doubt are significantly or even at all better than a well restored Stereo 20 or, say, a pair of Quad IIs, both of which are likely to retain or even increase their value, are easy to service, and are proven designs.

-- Ian

* I ought to make clear to everybody that mine's not for sale, so this isn't me doing a sales pitch

 

Oh, I was just mailing you an offer of about 30k £ for it.
Well then I'll buy tomorrow a new car instead.

 

Chris Found (who designed the valve filter unit that was commissioned for my bass speakers) does some excellent mods for the old Leak valve amps that might be worth looking into. Andy Evans of the London Hi-fi Circle will also do the mods. He can be found on the Leak Forum.

 

Hi Dev,
I guess that you are comparing the Leak Stereo 20 to the WAD 6550? I have heard that WAD in my system and it is certainly a 'take no prisoners' amplifier, it is primarily marketed at the school of thought that thinks the more Watts the better and to tempt people away from Solid State. Have you seen these threads from PFM?
Building a WAD 6550.
Review of the WAD 6550.

I'm not surprised that you are torn between the two styles of valve presentation:
The Stereo 20 with the sweet sounding EL84 valves and relatively small (by today's standards!) transformers.
The WAD 6550 with the muscley American 6550 tubes and big transformers.
I'd guess the former to sound quite soft and magical compared to the grippy and attention grabbing sound of the latter.

It might be worth investigating the cheap little WAD KEL84, this is considered to be the best value for money kit that WAD have produced. I would expect that it could offer a halfway house between the two amplifiers I have commented on above as it is a modern design using the same sweet EL84 valve as the Leak.

Have fun!

 

I fully agree with what Ian said, unless you are going to spend a lot more than £300-400, you will not easily find a better valve power amp than a Leak Stereo 20. Just make sure all the old electrolytic caps and out of spec resistors are replaced. It may not have the tightest bass compared to modern valve amps, but the ST20 is sweet and clear. The 10W output power is enough for medium sensitivity speakers.

The depreciation of a ST20 will be zero after a few years, it holds its price well. Good luck.

Regards
Hon

 

After further listening, the Leak is slightly ahead . My heart missed a beat or two a couple of times when I heard a loud pop when switching off the amp in use. Wish they wouldn't do that!

 

Take the bottom plate off the Leak Dev, and have a look at the layout!

Its a great one to play "swap the component" games with... all the resistors and caps are laid out in perfect straight little lines.

Incidentally, I've never heard the Leak pre-amps, but they are supposed to be not as good as the power amps, so it would be worth trying a few different pre's.

Are you using a pre-out on your MF to do the auditions? Or have you got a valve pre to do the demos with?

One thing that I am thinking.. you seem more attracted to the sound of EL84's than 6550's (a gross exageration on my part based on just 2 amps), perhaps this preference is due to your speakers already having a lush full sound. To my ears EL84 amps are a bit leaner sounding.

A 300B push pull or SET amp is also leaner sounding, and I think the 300B push pull amps from WAD certainly seem to be one to put on that shortlist.

Incidentally, if you dont fancy doing the build on a kit, there are people who can do a proffessional build for you for a couple of hundred quid.

Cheers!
Chris

 

Ooo... do keep us posted on how the Rogue sounds...

JJ

 

I reckon the KEL is better than the Leak by quite a way. I've had both. The KEL does everything the Leak does but sounds more modern, much faster. Its very much a cross between the two in fact.
The 6550 is a better amp but you have to do alot of work on it for it to really show. Power aside, for the most part the presentation of the KEL and KAT/KIT is actually very similar (not at all suprising when you look at the circuits- they're pretty much exactly the same- only real difference is the KEL has solid state rectification and the KAT has valve rect. Doesn't seem to make a huge amount of difference either way in use imo). Its only when you put real quality components in that the 6550 really starts to pull ahead further (especially in the bass range) but for the most part the kel runs it pretty close. Its definately a good place to start- dead easy to build and very good vfm.

 

Ian's Leak does not have a bottom plate and Ian showed me the layout. It is a nice arrangement of new (it's been rebuilt) components in a straight line as you say.

I'm using a passive pre that Lee had. I understand you "heard" it at your bakeoff a couple of years ago. I have not used the MF pre-outs, since that is supposed to be the weakest link in my system.

I've spoken to WAD and he's going to send me a set of KT88s to try and the 300BPPs when they come back to stock. If I go for the WAD, I'll opt to build them, just to ensure they are unique.

Still cannot contact Nick at the Emporium, have left messages.

 

Just reading through the thread now and it shows how we all have different opinions about things. This is why auditioning is essential. I for one feel that a refurbed ST20 kills a KEL84 for instance.

I feel that a 300b PP could be really good with the Tannoys, so they could be fun if you get them.

I will have to get over. I can bring a pair of Quad II's, some home built things and if I get the soldering iron warm a Golden Tubes EL34 amp. 9th July could be good.

 

At the moment 9th looks good Lee. Hopefully I'll get the 300BPP by then. I'll let you know.

 

Yes, I'm not really one for 300b tbh, I find them vague and rolled off.

If you want to hear a kel, your welcome to listen to mine if you can get here, in Penisborough at the moment. Not ideally setup in my completely square room but good enough.

 

Blah blah blah.

To add to the valve chit-chat:
Many years ago a late friend of mine bought an old Rogers Cadet (EL84s again?) around to add to the ambience of a malt whisky appreciation night - I forgot about the Dalmore, Rosebank and Bowmore and fell in love with the magic appearing through this knackered, hissy old beast.
A few years later another friend bought an Audio Innovations Series 700 from a Hi-Fi Reviewer which I envied, sadly for him the head honcho for AI politely asked for it back (after he quoted them the serial number). Naughty Hi-Fi reviewer!
I then nearly bought a Leak Stereo 20 (from Hi-Fi Experience near London Victoria Station) but waited for over 5 years before buying my first valve amp. That was an AI s500 which I loved for a couple of years until I spotted a bargain WAD power amp. on eBay - their old 300B PP (stereo chassis) which is superb. I added a passive pre and the excellent WAD phono kit and have gently tweaked all of them to my satisfaction.
People often slate the 300B valve as being a little bit bloated in the bass and soft in the treble. I use the Electro-Harmonix Gold Grids in that amplifier, which into my 'speakers (Heybrook Sextets) sounds a little lean bass-wise but have plenty of sparkle and 'air'. The dryness and some of the sparkly character is, I believe, more to do with the 'speaker than the amplifier...

Which brings me to my conclusion - matching an amplifier to a loudspeaker is fairly important, but with valves it is crucial.
Almost as tricky as matching a cartridge to a tonearm.
Almost!

Transducers, eh? Who'd have 'em!

- - - - - - - - - - - - - - - - - - - - -

Anex,
Having experience of both, what has the bigger Output Transformers - the Leak Stereo 20 or the WAD KEL84?

 

What about that affordable valve company? Does anyone still buy from that fella? His claims were amazing a few years back???

 

shhhh, don't go there, the can of worms you are holding is enormous. put it down and back away....
cheers


julian

 

ST20 trans are about twice the size but the KEL are better quality. Why?

Re 300B- I heard a Paul Barker demonstration, theres nothing wrong with them but the other stuff he was using (px's) were along way ahead.