Pros and cons of valve amps

[Marco]

A few exceptional valve amps of 100WPC may manage 30-40W at 20Hz but that would be very unusual and takes humongous output transformers to manage it.

Interesting... Anthony, what are the relevant specs here, in relation to the Copper amp? I may be wrong (as we were chatting away at the time and I wasn't paying full attention), but I'm sure the last time I was down, when you were measuring my amp, it was producing something close to the bit in bold above, as quoted by Jez

Marco.

[Gazjam]

"Brown note" depth of bass here, tight tuneful and thudding you in the chest.
Volume control between 8 and 9 o'clock depending on the music, any louder and the acoustic guitar on the back wall starts vibrating along...which is offputting!

Pushed it to 12 o'clock once on some chamber music and the thing just kept accellerating, no loss of control at the low end.

All from only 8watts a side triode valve amp in a medium sized room.
Contradictions in every amp type...

[Marco]

Yup, same here, mate. However, we do own exceptional examples of valve amps, designed by folk who *really* know what they're doing and how to get the absolute most from that topology!

What you're describing is, IMO, also to do with why folk often claim that 'valve watts' are seemingly more 'powerful' than SS watts, which is often why a well-designed, low-powered valve amp can sound subjectively bigger and 'gutsier' than a (significantly) more powerful, in terms of watts, SS amp.

For me, there's definitely something in that [no proper idea why, though] as I've heard the effect MANY times. Certainly, the Copper amp goes subjectively just as loud (whilst staying in control of the music), as did my old 200W ECS monoblocks - and I'm sure your 8W SET amp does the same in comparison with, say, any 30W SS amp you've heard.

I think Anthony had a theory about it, along the lines of valves being high-voltage devices, so the power is 'always there' and available instantaneously, whereas with SS amps the delivery isn't as immediate, or something like that... Perhaps he will elucidate?

Marco.

[Haselsh1]

With regard to sheer slam and transient speed, my current valve power amp way outstrips any of my old SS amps. It does not however have that easy, effortless low frequency that some of my SS amps have had. Of course this could just be a damn fine synergy with my current loudspeakers.

[Arkless Electronics]

Well, all I can say is that, awkward load aside, despite trying many times, over the course of the last 10 years or so since I've got into valve amps, I've *yet* to hear that, and trust me I've had some serious SPLs going on in my listening room, and others I've tried it in, with both high-quality SS and valve amps...

Maybe one day I'll pop up to your place with the Copper amp and you can demonstrate where you're coming from, in the form of a listening test, with some appropriate music? As ever, as they say, I'm 'all ears' and keen to learn!










Marco.

I'd rather prove it with measurements. They would make it very obvious. My speakers are nearly as efficient as your Tannoys and I have a small listening room in a flat.... We'd be rendered half deaf and dealing with all the police vehicles in attendance if trying to prove it subjectively!

It is certainly technically possible to build a 100WPC valve amp that still gives full output @ 20Hz but it is hardly ever seen in practice due to the size, weight and expense of output transformers (OPT's) required. Obviously as power goes down it becomes easier and cheaper to use OPT's that can handle it. My Stereo 20 for example has OPT's that look big enough for a 40WPC amp and yet it is only rated at 10WPC. Due to this I wouldn't be surprised if it could give full output at 20Hz.

Conversely if one looks at the OPT's in a guitar amp then in some cases the ones in a 100W amp look only adequate for about 30W if used in a hi fi amp. They aren't being called upon to amplify anything much below about 100Hz and any distortion is considered part of the signature tone of that guitar amp anyway!

As an aside there would once have been valve amps made for driving "shaker tables" which are used for testing the resistance to vibration and maximum allowable G force of whatever object/product is being tested. Some of these would have produced a KW or more at 10Hz so it can certainly be done!! The OPT though would probably have been the size of a fridge and weighed 1/2 Ton or so...

[Reffc]

Well, this is another of those threads that will either unite, or devide us!
Excelent resusts can be atained by either technology, you just have to know how to implement each topology, to get the best out of it.
My own choice for Single ended was a Hybrid design, although I chose to use the solid state devices to drive' and control the valves, rather than doing away with the output valves and transformers etc.
Anyone who has heard the Soul amps will I am sure, agree that they do not sound like typical valve amps, let alone single ended ones!
The argument of which technology is best will' I am sure rage on, until well after many of us here have shuffled off into the sunset, However, I stand by what I have said here, and many times in the past, when you partner a decently well designed Valve amp to the right speaker, you will imediately realise what it is about the technolgy that keeps them in the limelight, and why I am sure they will still be around in many systems for the foreseeable future.

I agree Anthony. It's about the end result, irrespective of the technology employed, but I'm with you on your conclusions.

There are good examples of various types of technology, but I know which I prefer when using sensible high efficiency loudspeakers that don't present awkward loads. The pros & cons of one tech to another barely even come into it when comparing even the bass performance, (that's more a factor with awkward loudspeaker loads) because a competently designed valve amp will manage 20Hz-20KHz +/- a sensibly low variance and without high distortion. Problem is, we've been flooded with loads of poor quality valve amps on the market since their resurgence (including plenty of expensive ones), so folks do have to search the competent designs out which demands seeking supplementary information that often some manufacturers don't provide (nor are really willing to). Having heard your Copper amp, I'm sure that comes into the "competently designed" camp

[Arkless Electronics]

Yup, same here, mate. However, we do own exceptional examples of valve amps, designed by folk who *really* know what they're doing and how to get the absolute most from said topology!

What you're describing is, IMO, also to do with why folk often claim that 'valve watts' are seemingly more 'powerful' than SS watts, which is often why a well-designed, low-powered valve amp can sound subjectively bigger and 'gutsier' than a (significantly) more powerful, in terms of watts, SS amp.

For me, there's definitely something in that [no proper idea why, though] as I've heard the effect MANY times. Certainly, the Copper amp goes subjectively just as loud (whilst staying in control of the music), as did my old 200W ECS monoblocks - and I'm sure your 8W SET amp does the same in comparison with, say, any 30W SS amp you've heard.

I think Anthony had a theory about it, along the lines of valves being high-current devices, so the power is 'always there' and available instantaneously, whereas SS amps have to 'search' for it, or something like that... Perhaps he will elucidate?

Marco.

Sorry but complete gobbledygook and wrong in every way... Valves are LOW current devices for a start and some bits are so "out there" I ain't even going to address them!
As to valve Watts seeming louder this is manly due to softer clipping and less offensive distortion when they do clip. The higher the NFB used in a valve amp then the better the measured performance (as in the Radford) but the more similar it will be to a SS amp in terms of clipping performance and subjective max loudness.

[Arkless Electronics]

I agree Anthony. It's about the end result, irrespective of the technology employed, but I'm with you on your conclusions.

There are good examples of various types of technology, but I know which I prefer when using sensible high efficiency loudspeakers that don't present awkward loads. The pros & cons of one tech to another barely even come into it when comparing even the bass performance, (that's more a factor with awkward loudspeaker loads) because a competently designed valve amp will manage 20Hz-20KHz +/- a sensibly low variance and without high distortion. Problem is, we've been flooded with loads of poor quality valve amps on the market since their resurgence (including plenty of expensive ones), so folks do have to search the competent designs out which demands seeking supplementary information that often some manufacturers don't provide (nor are really willing to). Having heard your Copper amp, I'm sure that comes into the "competently designed" camp

Many will do 5Hz to 100KHz +/- 1dB.... if you only want half a Watt from a 100WPC amp!!! The rest I can't argue with

[Marco]

Sorry but complete gobbledygook and wrong in every way... Valves are LOW current devices for a start...

Yes, sorry I meant voltage, not current. I shall amend my post accordingly.

As to valve Watts seeming louder this is manly due to softer clipping and less offensive distortion when they do clip. The higher the NFB used in a valve amp then the better the measured performance (as in the Radford) but the more similar it will be to a SS amp in terms of clipping performance and subjective max loudness.

Can't dispute that, but I suspect there's also a little more to it than that. In that respect, I'll wait for Anthony to return to the discussion and put the point I raised earlier into a proper context.

Marco.

[plastic penguin]

Personally I think Valve amps, in the main, look too industrial. There are some makes like Graaf or hybrids that look decent -- and not designed by Isambard Kingdom Brunel.

I know it's very subjective, and wouldn't knock anyone for owning or looking to buy a valve amp. At this moment, I can't imagine owning a traditional valve amp. Perhaps in 10-years or so... not now.

The thread was only started because I wanted to get a wide range of views on the subject.