A tale of two amplifiers

[farflungstar]

Ok, so I've been happily going along listening to and loving my system which in brief is Allaerts cart, custom built sigwaan wooden arm, Technics SP10 feeding a Hashimoto sut, feeding a Vida phonostage feeding a The Truth line stage feeding Cary 805c monoblocks into audio note ane spx speakers.

The Cary's 300b and 845 tubes give out a ridiculous amount of heat and here in Spain in summer it's not pleasant or sensible to run them. So I bought a Hiraga amplifier from Jake aka lordmortlock with the intention of using it in summer. Here it is.

https://uploads.tapatalk-cdn.com/20170819/d8fd01627923d806d750def77eb25c82.jpg

I really didn't want to swap amps and shillishallied for weeks before finally hooking up the Hiraga. Wow - jaw dropping moment after letting it play for a couple of hours before sitting down. Jaw dropping.

It beats the Cary's in bass dynamics to an astonishing degree, it's less refined in the top end but gosh does it play loud - way louder than the Cary's and without any breakup. It's less liquid but it's better controlled and although it has less depth the soundstage is wider and out of the speakers in a way the Carys just don't do. It truly sounds exceptionally good with a bottomless low end, sweet midrange and a top end that isn't the most refined. But gosh does it make you want to listen to music.

The Cary's are rated at 45-50rms in class A - the Hiraga 20 in class A - so how come it goes louder, has more balls? Are the Cary's in need of a service and total overhaul? This is my suspicion - but we're talking a lot of moolah.

I recently started a post about pimping up the Hiraga with better components - because I could quite happily live with what I'm hearing but I know that with it's age some components may be out of spec. If only I had a Jez living down the road!

[User211]

If it is any help my 80 Watt 211 monks blow AN/Es wide open and sound very dynamic and ballsy.

A much less powerful 211 based AN Tomei sounds markedly similar sharing many traits if not quite the same volume levels. Still very good SPL delivery though. Way better dynamically than any other AN amp I have heard on AN/Es and I have heard a good few.

So maybe the Cary's are fucked. Hard to tell without being there.

[farflungstar]

I have a feeling you may be right.... Something else to add to the hi fi list of purchases. Though I have to say this Hiraga is extraordinarily good and I've never had SS in my life! Of course it's unfair to compare when the Cary's may be fucked. There must be a synergy because I've never heard the anes sound so alive.

[User211]

See what you think in three months time. Seriously. Changes are as good as a rest. Wow moments sometimes. Then constant exposure to the new sound often results in less than the initial enthusiasm.

[montesquieu]

Can't say I was overly impressed by the Cary 300bs I heard. And while I'm not a huge fan of AN-Es ( despite trying out three different pairs of ever more expensive ones from AN HQ ) the best I've ever heard them was with a seriously tricked out chip amp - better even than the Jinro I heard with one pair. So nothing surprises me here.

[rubber duck]

Have to agree with Tom that Cary amps, especially the 300Bs, are the woolliest, softest of the 300B species I've tried. A Tripath amp will give you similar improvements in bass and dynamics.

[paulf-2007]

50w rms in class A from a 300B, I doubt that very much. It's not a hybrid is it. Solid state will give more controlled bass. The reason I ran three amps with my horn set up. The best of all worlds. Compromise is the name of this hifi game.

[paulf-2007]

Ok, scratch that, having looked into it the 300B is the driver.

[farflungstar]

50w rms in class A from a 300B, I doubt that very much. It's not a hybrid is it. Solid state will give more controlled bass. The reason I ran three amps with my horn set up. The best of all worlds. Compromise is the name of this hifi game.The 300 is the driver - 845 tubes output and certainly not wooly. The 805c's are highly regarded - but I bought these 2nd hand and they are over 10 years old. Maybe the seller decided to move them on rather than pay out the not insubstantial amount needed for service and upgrade.

[Haselsh1]

Adrian, my partner Sue and I absolutely bloody love moments like this. Jaw dropping realisations. Absolutely brilliant.

[farflungstar]

I guess the Cary's are just gonna have to go for service and upgrade - I'm thinking maybe the power caps are shot but I'm no Jez arkless. Unless you've seen and lifted an 805c it's difficult to understand the over engineering that's in them. The trannies are the biggest I've ever seen and they weigh in at 45k each monoblock. They make most other amps look puny and fragile. They are however a dog's dinner internally. With bench time and upgrade components I'm looking at around €1500 - the price of a good second hand alternative.

As regards the Hiraga - I do wish Jez lived in sunny Spain so I could get it checked out and any components changed - but it sounds great, revealing new details in well known tracks, and giving pin point imaging that the Cary's don't.

[fatmarley]

With the differences you describe, I can't Imagine upgraded component giving you what you want - Well, you may be lucky but It's a big gamble.

[farflungstar]

The Cary's are knocking on for 15 years old and I doubt they've ever been serviced. I don't have a choice but to do it.

The Hiraga was a special build back in the day for Expolinear speakers and is branded Expolinear. I know Jake thought very highly of if and even asked if I'd consider selling it back to him, so it has merit beyond my own hearing. I'm just thinking that as it's also long in the tooth it might also need a service.

[oldius]

I guess the Cary's are just gonna have to go for service and upgrade - I'm thinking maybe the power caps are shot but I'm no Jez arkless. Unless you've seen and lifted an 805c it's difficult to understand the over engineering that's in them. The trannies are the biggest I've ever seen and they weigh in at 45k each monoblock. They make most other amps look puny and fragile. They are however a dog's dinner internally. With bench time and upgrade components I'm looking at around €1500 - the price of a good second hand alternative.

As regards the Hiraga - I do wish Jez lived in sunny Spain so I could get it checked out and any components changed - but it sounds great, revealing new details in well known tracks, and giving pin point imaging that the Cary's don't.


That's a lot of money. Why not try other SS amps to see if there is a preference there?

[farflungstar]

I'm considering that. But it would be an awful shame to have the Cary's sitting there or packed up. If I did it would be a class A job, maybe Krell KSA 80/100.

[Sherwood]

I would hold off on any amplifier decision until you've decided on your speaker upgrade, assuming that you are still planning to replace your current models.

Geoff

[farflungstar]

Yes Geoff, that's still the plan for September - just stuck between Omega or JMR Offrande Supreme.

[mac72]

The Cary's are knocking on for 15 years old and I doubt they've ever been serviced. I don't have a choice but to do it.

The Hiraga was a special build back in the day for Expolinear speakers and is branded Expolinear. I know Jake thought very highly of if and even asked if I'd consider selling it back to him, so it has merit beyond my own hearing. I'm just thinking that as it's also long in the tooth it might also need a service.
Did you check bias current on power valves , do you know how many hours valves have done so far , it might be as simple as replacing them wit fresh set

[farflungstar]

Yes bias is fine at 60ma.

[mac72]

Yes bias is fine at 60ma.
Have tubes ever been replaced ?
IF not I would try to find someone to test these , is very unlikely there is anything wrong with psu or amplifier

[farflungstar]

Tubes are less than 18 months old.

[mac72]

Tubes are less than 18 months old.

Tubes should be fine then , have amps serviced , if of any help here is a service manual ,(should help to trace parts) :
http://www.ainamoi.com/805c.htm

[Arkless Electronics]

The Hiraga's probably just a better amp than the Cary;)

[farflungstar]

The Hiraga's probably just a better amp than the Cary;)I can't quite believe that Jez.

[montesquieu]

I can't quite believe that Jez.

He might well be right.

The Es are funny to match though. I have a suspicion a Krell with them would be horrible (as it was with my Tannoy Golds). Synergy is all.

[oldius]

I am not a fan whatsoever of AN speakers. I didn't realise that you were intending to replace them but the advice posted is sound: get the speakers right first, especially their interaction with your room. Invite guests who are willing to bring a range of speakers for you to try. If they all sound better with the Hiraga then you have a much clearer path.

[mac72]

I can't quite believe that Jez.

Agreed , have them checked , it's a nicely designed amps ,
all coupling caps are oil filled , they don't like operating at high temperature for long time as they go out of specs , it shouldn't cost €1500 to check them over and replace few parts

[farflungstar]

The Cary's operate at stupidly high temperatures not only because of the 845 tubes but because of a resistor which uses the top plate to cool off - this makes it impossible to touch the top plate. I can imagine that any components close by are slowly cooked.

[farflungstar]

After a marathon 8 hours of listening to the Hiraga I can say it loses out to the Carys in overall sound quality, particularly depth and truth of timbre (if valves can do that). Where the Hiraga wins is width of soundstage and bass depth, articulation and slam, it also reveals a little finer detail but very little. The biggest difference is the way it energises the audio notes in a way the Carys don't. But of course the Carys haven't been serviced or upgraded in maybe 15 years so in September I'll ship them to Valencia and have them sorted.

[RothwellAudio]

I guess the Cary's are just gonna have to go for service and upgrade - I'm thinking maybe the power caps are shot but I'm no Jez arkless. Unless you've seen and lifted an 805c it's difficult to understand the over engineering that's in them. The trannies are the biggest I've ever seen and they weigh in at 45k each monoblock. They make most other amps look puny and fragile. They are however a dog's dinner internally.

Over-engineering is often just a fancy-sounding term for using unnecessarily large and heavy components without any particular design rationale other that it will impress the customer and justify a high price tag.


The Hiraga's probably just a better amp than the Cary;)
Yes, that would appear to be the obvious answer. If it walks like a duck and quacks like a duck....


I can't quite believe that Jez.
Yes, having spent a lot of money on something it can be hard to accept that it isn't quite what you thought it was.

[walpurgis]

Over-engineering is often just a fancy-sounding term for using unnecessarily large and heavy components without any particular design rationale other that it will impress the customer and justify a high price tag.

Bit like having a 700 bhp, 200 mph Bentley, in a country with a 70 limit and traffic congestion.

[farflungstar]

Over-engineering is often just a fancy-sounding term for using unnecessarily large and heavy components without any particular design rationale other that it will impress the customer and justify a high price tag.


Yes, that would appear to be the obvious answer. If it walks like a duck and quacks like a duck....


Yes, having spent a lot of money on something it can be hard to accept that it isn't quite what you thought it was.I would agree about over engineering. Although I'm not sure you can make a transformer too big in a valve amp as most respected manufacturers agree. However the Carys are recognised as exceptional amplifiers for bringing the SET 300b sound together with the balls and drive of the 845 tube - they are in the top ten amplifiers of all time according to certain publications, although I'm sure if you looked inside one you wouldn't agree!

It's perfectly logical that the Hiraga should outsmart the Cary's in terms of of power and drive, if not in your those subtle audiophile qualities we like such as depth of soundstage, tonallity, liquidity etc, when you think that the Cary's haven't been serviced or touched in 15 years and run hotter than a gridle. Once they are serviced then the comparison might be fairer.

It really isn't about money for me - I dont care if I discover something for £50 that pisses offer a £10k amp - I'd keep the £50 and sell the £10k. The Hiraga has surprising qualities and I understand why Jake offered to buy it back - but it does not have the qualities of a valve amp - a fettled valve amp.
Methinks.

[RothwellAudio]

Bit like having a 700 bhp, 200 mph Bentley, in a country with a 70 limit and traffic congestion.
Not quite. The point I was trying to make was that it would be a bit like having a 2 litre engine that performs no better than a 1 litre engine.


I would agree about over engineering. Although I'm not sure you can make a transformer too big in a valve amp as most respected manufacturers agree...
...the Cary's haven't been serviced or touched in 15 years and run hotter than a gridle...
True, but there's a limit to how far you can go with the design philosophy of "it's bigger so it must be better". A well-chosen resistor costing 2p can bring about dramatic improvements to circuit and be much more cost-effective, but you have to know enough about electronics to think of including the resistor in the first place.
Yes, running hot does shorten the life expectancy of components quite considerably. Maybe checking things out isn't a bad idea.

[alphaGT]

Can you bi-amp the speakers? Run the Hiraga to the woofers and the Cary to the tweeters, see what that sounds like?


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[farflungstar]

I'm toying with options, not having factored in spending money on amplifiers this year - I have a very good deal on a New Audio Frontiers 84&se but that would relegate the Cary's to their boxes which is a shame as theyre superb. Better to get them serviced and upgraded and keep them in use.

As to the Hiraga - I love it, but it has two failings and I'd like to try and address them. Depth of soundstage and a slight veiling. I know some people think its heresy to change anything but would upgrading caps, resistors help with this?

[User211]

What is in the Hiraga now in terms of components?

[Arkless Electronics]

I'm toying with options, not having factored in spending money on amplifiers this year - I have a very good deal on a New Audio Frontiers 84&se but that would relegate the Cary's to their boxes which is a shame as theyre superb. Better to get them serviced and upgraded and keep them in use.

As to the Hiraga - I love it, but it has two failings and I'd like to try and address them. Depth of soundstage and a slight veiling. I know some people think its heresy to change anything but would upgrading caps, resistors help with this?

Probably not.

[farflungstar]

What is in the Hiraga now in terms of components?Very little actually - it's true dual mono so aside from the transformer, heatsinks and the big power caps there's only two tidy circuit boards with less than a handful of caps etc between them, and there are already good quality components such as red Wima. It's simplicity is what I like about it.

I'm still listening to it and have no desire to switch back to the Cary's - if only it resolved depth better - but the Cary's are renowned for their spooky image depth.

I know some people either say caps don't make a difference or I shouldn't alter a classic - I think caps, resistors etc do make differences - I just need to know which ones would make the most difference.

As for altering a classic - im not a collector, im a listener.

[fatmarley]

Are there different versions of this amp? I don't know what the latest revision Is, but this one over at diyaudio has some extra components compared to circuit diagrams I've seen on Google - LINK (http://diyaudioprojects.com/Solid/Jean-Hiraga-Class-A-Amplifier/)

One of the circuit diagrams I saw on google has a single, small value cap decoupling the power rail but the one on diyaudio has an extra 22uf electrolytic. If yours Is an older model? you may be able to upgrade It to the latest spec If It Is.

[farflungstar]

Are there different versions of this amp? I don't know what the latest revision Is, but this one over at diyaudio has some extra components compared to circuit diagrams I've seen on Google - LINK (http://diyaudioprojects.com/Solid/Jean-Hiraga-Class-A-Amplifier/)

One of the circuit diagrams I saw on google has a single, small value cap decoupling the power rail but the one on diyaudio has an extra 22uf electrolytic. If yours Is an older model? you may be able to upgrade It to the latest spec If It Is.Thanks for that I'll check it out - mine is very old.

[farflungstar]

Two shots - one of the Cary, one of the Hiraga. In my opinion the Cary is bloody untidy for a £10k amp whereas the Hiraga is incredibly simple.https://uploads.tapatalk-cdn.com/20170825/a2fb96289831b2cdbe045cc93a11c1ff.jpghttps://uploads.tapatalk-cdn.com/20170825/7571a477485aaa87002c6464159e03d8.jpg

[fatmarley]

That looks like a later version of the Hiraga because I can see some polystyrene caps. Polystyrene Is as good as It gets, so there's no chance of upgrading those.

You could replace some of the lower wattage resistors In the signal path for Vishay Dale RN60, they are a smoother In the high frequencies than most other metal film resistors, but still sound clean and detailed. They just lose that slight edge you get with resistors like Vishay MRS25.

[farflungstar]

That looks like a later version of the Hiraga because I can see some polystyrene caps. Polystyrene Is as good as It gets, so there's no chance of upgrading those.

You could replace some of the lower wattage resistors In the signal path for Vishay Dale RN60, they are a smoother In the high frequencies than most other metal film resistors, but still sound clean and detailed. They just lose that slight edge you get with resistors like Vishay MRS25.Cheers..

[alphaGT]

Wow it is crowded inside that Cary!


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[Yomanze]

The Cary is significantly tidier than it looks!

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[farflungstar]

The Cary is significantly tidier than it looks!

Sent from my SM-G920F using TapatalkI wouldn't agree with you. It's a mess to my eyes lol

[Arkless Electronics]

It doesn't matter what it looks like! Electrons have no sense of neatness and very often the best layout is one which minimises wiring lengths and places crucial parts as close as possible to where they need to be. NOT in places which look symmetrical etc to the human eye!;) There's quite a few electrolytics I can see in there which could indeed do with replacing if it is 20 years old...

[farflungstar]

As far as I know Jez it has never been serviced and is between 15-20 years old. I just wouldn't want to be the guy servicing it! It will be going in at the end of September.

[RothwellAudio]

... very often the best layout is one which minimises wiring lengths and places crucial parts as close as possible to where they need to be. NOT in places which look symmetrical etc to the human eye!;)
Absolutely. I see lots of valve amps where the transformers have been placed in a neat row, then the power valves in a neat row, then the small valves in another neat row, etc. It looks very nice but isn't necessarily the best layout. I've seen amps where the mains transformer is in the middle of the back row and the input sockets are at each end of the back panel. Looks beautiful...but the L/R input earths have formed an earth loop with a mains transformer smack in the middle of it! Trying curing that hum with Cardas cable :lol:

[fatmarley]

I've been reading up on the Hiraga and apparently It has poor PSRR (power supply rejection ratio). It was suggested over at diyaudio that a CLC power supply would help.

It may be possible to fit an Inductor In between the main smoothing caps on your original supply but I'm not sure what value you would need. A supply that may work would be the Avondale Nap110 PSU (http://avondaleaudio.com/store/#!/Avondale-Audio-NAP110-Power-Supply-Upgrade-Module/p/37908428) upgrade. May be worth a phone call to Les.

[farflungstar]

I'll look into that...

[Barry]

Two shots - one of the Cary, one of the Hiraga. In my opinion the Cary is bloody untidy for a £10k amp whereas the Hiraga is incredibly simple.https://uploads.tapatalk-cdn.com/20170825/a2fb96289831b2cdbe045cc93a11c1ff.jpghttps://uploads.tapatalk-cdn.com/20170825/7571a477485aaa87002c6464159e03d8.jpg

The Hiraga design may be the simpler but to my eyes the wiring looks just as untidy. But whatever works!

[farflungstar]

What astounds me about this class A amp is it's similarity in tone to 300b/845 tubes, vocals are still as beautifully fleshed out, percussion is a level above, imaging is pinpoint, layering is better, depth is less but if it's on the recorded album it's there. This and all the above can be laid at the door of a certain 'bloom' and vieling that has disappeared. I think the Hiraga has met it's natural mate in the Ane's, but I miss looking at those glowing valves and thinking how incredible it is that they are helping make me feel good. Got to get the Cary's serviced.

[walpurgis]

Not astounding really. Surely, the better amps are, the less one should be able to tell them apart? :)

[Macca]

Not astounding really. Surely, the better amps are, the less one should be able to tell them apart? :)

True, but only in an objective sense. It is weird sometimes what people like and don't like. And in subjective-world, if they like it, then it's 'better'.

[Eaton Mess]

Hiraga does not have a monopoly on a SS amplifier sounding like valves or visa versa.

Seems like you are looking for an amplifier that combines the best attributes of both solid state and valves?

Have you thought of a hybrid like the croft valves and transistor.

There is a Berning ZH270 all valve but with many SS attributes of great bass control, speed, tone and timbre http://davidberning.com/products/zh270

There are also the Nelson Pass First watt solid state which are very valve like for example the SIT 1 and 2 http://www.enjoythemusic.com/superioraudio/equipment/1013/first_watt_sit_2_amplifier.htm





What astounds me about this class A amp is it's similarity in tone to 300b/845 tubes, vocals are still as beautifully fleshed out, percussion is a level above, imaging is pinpoint, layering is better, depth is less but if it's on the recorded album it's there. This and all the above can be laid at the door of a certain 'bloom' and vieling that has disappeared. I think the Hiraga has met it's natural mate in the Ane's, but I miss looking at those glowing valves and thinking how incredible it is that they are helping make me feel good. Got to get the Cary's serviced.

[montesquieu]

The Pass Sit amps are 10w single ended and would most likely be pretty hopeless with Tannoys. I’ve tried the push pull 25w First Watt amp (can’t remember if it was an F5 or F3) and it was ok but easily bested into my HPDs by a Radford STA25. Nicely made and I’m sure fits well in other applications.

I’ve heard the Berning amps sound good with other setups but haven’t had any in my system to compare - in theory they should work well with the caveat that OTL amps can sometimes have high output impedance (the Crofts suffer from this) which Tannoys most definitely don’t like.

Not tried any hybrids - if going solid state something like the Hiraga would seem to offer a more coherent approach.





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[Eaton Mess]

The Pass Sit amps are 10w single ended and would most likely be pretty hopeless with Tannoys. I’ve tried the push pull 25w First Watt amp (can’t remember if it was an F5 or F3) and it was ok but easily bested into my HPDs by a Radford STA25. Nicely made and I’m sure fits well in other applications.

I’ve heard the Berning amps sound good with other setups but haven’t had any in my system to compare - in theory they should work well with the caveat that OTL amps can sometimes have high output impedance (the Crofts suffer from this) which Tannoys most definitely don’t like.

Not tried any hybrids - if going solid state something like the Hiraga would seem to offer a more coherent approach.





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Its supposition as to what the end result any of these amplifiers would be with the Tannoy's BUT one thing I have learned over the years power output is no indication as to how an amplifier will perform with a given speaker. Personally I have no direct experience of these amplifiers with these speakers but Nelson Pass does.

https://www.dagogo.com/wp-content/uploads/2015/12/NelsonPassVisit2015-3.jpg

By coincidence the First Watt SIT-2 is I believe 20 watts as is the Hiraga

Here is a link to a couple of articles which covers Nelson Pass and his love among other speakers the Tannoy HPD
https://www.dagogo.com/a-pass-labs-experience/
http://positive-feedback.com/Issue78/nelson_pass.htm

I have owned Radford in the past and as you say should probably be a good match but its sound is fairly typical of its output tube type. However; that does not seem to be what @Farflungstar is yearning for. He seems to be saying he wants the best attributes of tubes (Cary) and Solid State (Hiraga) so perhaps he needs to look at amplifiers which have these traits. Personally I value these attributes too

The Berning is a unique amplifier both in design and IMHO sound too. You mention the issue of output impedance and this is something David Berning has catered for by offering three switchable settings. Typical output impedpance (measured at 1 amp, 60Hz): 1.8 ohms, NORM feedback; 3.8 ohms, MED feedback; 8.7 ohms, LOW feedback. If @Farflungstar were in the UK he would be most welcome to borrow my ZH270 for a whirl with the Tannoy's as I would be very interested in the end result myself!

[montesquieu]

Its supposition as to what the end result any of these amplifiers would be with the Tannoy's BUT one thing I have learned over the years power output is no indication as to how an amplifier will perform with a given speaker. Personally I have no direct experience of these amplifiers with these speakers but Nelson Pass does.

https://www.dagogo.com/wp-content/uploads/2015/12/NelsonPassVisit2015-3.jpg

By coincidence the First Watt SIT-2 is I believe 20 watts as is the Hiraga

Here is a link to a couple of articles which covers Nelson Pass and his love among other speakers the Tannoy HPD
https://www.dagogo.com/a-pass-labs-experience/
http://positive-feedback.com/Issue78/nelson_pass.htm

I have owned Radford in the past and as you say should probably be a good match but its sound is fairly typical of its output tube type. However; that does not seem to be what @Farflungstar is yearning for. He seems to be saying he wants the best attributes of tubes (Cary) and Solid State (Hiraga) so perhaps he needs to look at amplifiers which have these traits. Personally I value these attributes too

The Berning is a unique amplifier both in design and IMHO sound too. You mention the issue of output impedance and this is something David Berning has catered for by offering three switchable settings. Typical output impedpance (measured at 1 amp, 60Hz): 1.8 ohms, NORM feedback; 3.8 ohms, MED feedback; 8.7 ohms, LOW feedback. If @Farflungstar were in the UK he would be most welcome to borrow my ZH270 for a whirl with the Tannoy's as I would be very interested in the end result myself!

Well my experience with many different sets of Tannoys and thirty-odd amps tried with them is that for the most part (with a few very rare exceptions) single ended designs don't work terribly well. I used HPDs myself currently. The output impedance figures for the Bernings bear out my concern - Tannoys need a decent damping factor to perform properly (which is exactly the issue with most SET amps).

A properly functioning Radford BTW is the opposite of 'typical tubey' - not sure where you got that? Have you ever heard one?

I agree that watts often have little impact on things - I have a Leak Stereo 20 whose 12 watts drives HPDs surprisingly well, though it is better suited to Monitor Golds. But most Tannoys do respond well to having a few watts up them. Again speaking from (lots of) experience.

[farflungstar]

I don't think I've ever been so worried about investing in an amplifier before - for so long I've wallowed in the magic of SET and to now be thinking of other topologies is scary. I think that's why I'm stuck on the Leben - is known to work very well with Tannoys, and the ability to change a good amount of different tubes means I can voice the amp to a degree.

[Macca]

Not knocking Leben, the only one I have heard was very impressive, but you should really consider a Radford too if it is within your budget. They don't sound 'tubey' but they have a rightness to the harmonics that can make other amps sound broken by comparison.

[montesquieu]

Indeed. In my view having owned both the sta25 sounds better than the 660p. The 1000p otoh is a different beast entirely


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[farflungstar]

If the dickhead on eBay would post the 1000 it would be in my system!

[Eaton Mess]

Well my experience with many different sets of Tannoys and thirty-odd amps tried with them is that for the most part (with a few very rare exceptions) single ended designs don't work terribly well. I used HPDs myself currently. The output impedance figures for the Bernings bear out my concern - Tannoys need a decent damping factor to perform properly (which is exactly the issue with most SET amps).

A properly functioning Radford BTW is the opposite of 'typical tubey' - not sure where you got that? Have you ever heard one?

I agree that watts often have little impact on things - I have a Leak Stereo 20 whose 12 watts drives HPDs surprisingly well, though it is better suited to Monitor Golds. But most Tannoys do respond well to having a few watts up them. Again speaking from (lots of) experience.

Yes I would agree a typical SET is unlikely to be the best match, especially in view of those large cones :eek: But then we are not talking about typical amplifiers here.
The Berning aims to maintain a constant output impedance across the entire audio spectrum and has some of the best controlled and textured bass I have heard form a valve amplifier. The Berning is Push Pull - Zotl not single ended but does have many sonic attributes of a SET but with much better extension at the frequency extremes.
Many valve amplifiers, including those you mention have very low damping factors I believe so on the face of it they would not be an ideal match. On the other hand solid states tend to have very high damping factors so should be ideal. However its not as simplistic as matching a nominal 8 ohm speaker with a quoted amplifier damping factor at a certain frequency. I have copied here an excellent explanation from Paul Coupe of this parish (who i'm sure you are very familiar with) from another forum which discusses the issue of Damping factor and the Tannoy HPD Driver

The degree of damping factor required is really dependant upon the speakers being driven. Some loudspeakers can get away with a very low damping factor (eg horn speakers driven by single ended amps) and its not the be all and end all. What matters is that you understand your speakers impedance characteristics. Unfortunately most manufacturers only ever supply a thing called "nominal impedance" for their speakers which tells you next to nothing. On its own, its not enough to select a matching amp.

For example, take Tannoy's HPD drivers. The 12 inch versions have a nominal impedance somewhere close to 7 Ohms, and are 92dB sensitive (note I didn't say "efficient" which is a different measure).

That looks like an easy load and you'd be forgiven for thinking so, until you see the actual impedance plot from a speaker using this driver. let me enlighten further.

Here's an actual impedance plot from HPD equipped speakers:
https://i.imgur.com/bWX3AIb.jpg

That 7 ohm nominal load and high sensitivity doesn't look as benign now does it?

So what happens if you drive speakers like these which have an impedance plot resembling the Alps with an amp having a very low damping factor?

Well first you need to consider total load resistance which is also made up of the reactive impedance and DCR of the speaker cables to get the total speaker load. This at any point on the impedance curve is divided by the output impedance of the amp to give you a damping factor.

What is immediately apparent is that if your impedance curve isn't linear (for example, impedance correction circuits haven't been employed in the crossover) is that the damping factor will VARY with frequency.

At low frequencies, generally speaking, the damping factor lowers and the amp loses grip on the speakers, so the critical thing is to find the lowest impedance response (usually in the bass area somewhere slightly above driver resonance) and calculate the required damping factor on that so you can be sure that at higher impedance values, there'll be no problem. As Col says, slew rate is also important, but at the moment, we're just looking at generalisms to help understand the importance of damping factor.

In reality, it doesn't have to be that high. Even for the Tannoys shown, a damping factor of say 10 is more than adequate, so amps boasting of a factor of 100 or more, well imho, that can be misleading in terms of they don't control the speakers any better than one with ten times less damping.

If you use speakers which exhibit a very linear impedance variation across the frequency bandwidth (and by linear I mean within a few Ohms) then you probably can get away with very low damping factors (and here, single ended valve amps with enough grunt should be sufficient).

What matters more in many cases is power output because the other important thing to note is that you can destroy tweeters by driving speakers hard with an under powered amp, so generally speaking, whilst you cannot afford to under - drive speakers (using solid state amps) you rarely have to worry about using high powered amps (you still have a volume control!).

The exception is valve amps where you can drive them into even order distortion without square wave clipping damaging speakers...they just sound more euphonic and long run it wont do the valve life much good but you're less likely to damage speakers.

Another point worth making here is that when looking at the figures for damping factors quoted, initially high damping factors look to be the way to go, so faced with say a valve amp with an output impedance of 1 Ohm or a SS amp with an output impedance of say 0.05 Ohms, and you have a set of speakers which are a nominal 8 Ohm load, you'd be forgiven for thinking that the comparative damping factors are 8 for the valve amp and 160 for the SS amp.

That would be wrong as an assumption though as it negates reactive impedance and the combined resistance the amp sees in the crossover circuit and speaker voice coil itself.

Take the above example and lets assume a simple 1st or 2nd order crossover. the first thing the amp sees when driving the speaker is an inductor and typically, the bass inductor would have a DCR of about 0.25 Ohms. The speaker voice coil is the next point of significant resistance and this typically for an 8 Ohm unit might be say 6 or 7 Ohms DCR, so lets use 6.5 Ohms.

Take the original SS output impedance and then add 0.25 plus 6.5 to it and we have a total of 6.3 Ohms, so the corrected damping factor now becomes 1.27. Do the same for the valve amp and the corrected factor becomes 1.03, so not a million miles adrift from the SS amp.

This is often forgotten about when comparing amplifiers.

For the Tannoys shown in the above example, a well designed valve amp, something like say a Radford (output impedance of just 0.18 Ohms) performs almost as well as many SS amps.

What you have to consider too are the power requirements which not only vary according to the speaker sensitivity but also with inertia and acoustic loading. So a sealed cabinet with a "Q" of around 0.7 using a 6 inch paper cone will be an easier load than say a 10 inch polypropylene driver in a bass reflex enclosure which will take a higher power and damping factor to control it, even if both have identical nominal impedance and sensitivity. Typically, bass reflex drivers have an electrical "Q" of around 0.3 to 0.5 as the lower value basically means a stronger magnet/drive mechanism, whereas sealed units can get away (and indeed need) lower strength magnets if they are not to become over damped.

So speaker inertia, damping factor, size and type must also be considered when looking at what constitutes an adequate damping factor.

Output impedance of any source or amplifier Ben is simply the summed resistance to passing an alternating current at a specific frequency made up of total resistive, capacitative and inductive elements of impedance. It varys according to the type of circuit employed.

Using generalisations again, when looking at say a preamp with an output impedance of 150 Ohms, this can be considered as a "perfect" source with 150Ohms resistance in series with the output looking at it simplistically.

Where a power amp is concerned, you don't want the amp behaving inefficiently, you want as much voltage and current that the circuit's designed to provide going straight to the speakers. The higher the output impedance, the less power is available to drive the loudspeakers.

Its a little more complex though (isn't it always) as looking at power amps there's two impedance definitions to consider: rated output impedance and actual output impedance. The former is the rated impedance that the amplifier can drive without becoming unstable or failing (so amps are rated usually into 2, 4 or 8 Ohms) and actual output impedance is usually calculated from the loudspeaker load and damping factor:

Z(actual) = Z(Loudspeaker total load)/(Damping factor). For many amplifiers (solid state) the value of Z(actual) is often less than 0.05 Ohms at 1KHz.

As to what makes up output impedance, well the type of circuit does rather than any one component.

If we look at a couple of examples, and take first a bog standard push pull valve amp using 6550 valves in the output stage, two valves per channel with a 5KOhm primary transformer winding then the sum plate impedance is 10KOhms. If the 2ndary winding has an impedance (typical) of 8 Ohms then the impedance ratio is 625 so total output impedance is 10KOhms/625 = 16 Ohms. This is WAY too high so most amps use what's referred to as a negative feedback loop to reduce the output impedance. In order to get it down to acceptable levels, around 20 to 30dB of feedback is employed. Some say that the use of negative feedback destroys the purity of the signal but it is essential to keep the amp stable into difficult loads.

This is where some single ended amps can actually score well, particularly if using a little negative feedback. If we look at a typical 300B valve amp, and say the primary winding was 4KOhms and the secondary 8, the impedance ratio is 500. If you then look at the tube plate impedance of a single 300B it's 680 to 700 Ohms.
The output impedance without feedback is then 700 divided by 500 = 1.4. A little negative feedback can get this figure appreciably lower so I simply don't understand why manufacturers insist on the rose tinted glasses which accompany the purist thought of zero negative feedback single ended amps, when clearly, a little feedback is a GOOD thing. EAR for example use a little negative feedback with the 869 to achieve a very low output impedance capable of driving surprisingly difficult loads with a modest 15wpc.

[montesquieu]

On the other hand solid states tend to have very high damping factors so should be ideal. [/COLOR]

Long experience with Tannoy DCs suggest the opposite. Tannoys are best with a damping factor somewhere the (conceptual) middle - I would say between 10 and maybe 30 or 40 with an optimum of 20 or so. So single ended amps are out (for the most part) as they have insufficient damping factor - while they will drive Tannoy DCs and there will often be plenty of bass, it won't be the nice, taught, well defined kind. (This may not matter so much in a small cabinet where there isn't much low bass to speak of anyway).

High power solid state on the other hand typically (though again, not always) has too high a damping factor resulting in the life being sucked out of DCs - a perfect example would be the Krell KSA100 I tried out a while back. Truly awful with Tannoy MGs, though I'm sure it has a place driving multi-driver speakers with complex crossovers, where its vice-like characteristics are far more welcome.

I know Paul very well, he designed my speakers (taking into account my room measurements and nodes), built my crossovers and has spent quite a bit of time in my listening room. I think he'd concur with the above.

Also like Paul I think the superstitious aversion to modest amounts of negative feedback used intelligently is retrograde thinking. I believe amplifiers should be designed by a judicious combination of measurement and ear. Not by religious dogma. (It's not a bad approach to choosing one either).

I would love to hear the Bernings with my Canterburys, they have a good reputation with Quad ESLs (of which I'm also a former owner) and intuitively amps that are good with the original ESLs also tend to work well with Tannoys.

[Radford Revival]

For what it's worth an STA25's output impedance is approximately 0.2 ohms (Occasionally it dips even lower depending on the valves) in the mid-band, which for a valve amplifier is very good indeed - low enough so that it is hard to differentiate the subjective effect of damping from a "0 ohm" source solid state design

There are certainly unconventional (ie not your standard high feedback class A/AB type) solid state designs out there with a much higher output impedance, as well as higher distortion!

[montesquieu]

For what it's worth an STA25's output impedance is approximately 0.2 ohms (Occasionally it dips even lower depending on the valves) in the mid-band, which for a valve amplifier is very good indeed - low enough so that it is hard to differentiate the subjective effect of damping from a "0 ohm" source solid state design

There are certainly unconventional (ie not your standard high feedback class A/AB type) solid state designs out there with a much higher output impedance, as well as higher distortion!

I was astonished at the STA25 I'm running at the moment (I'm using it while the Radford STA100 is away being restored). It had 90% of the big Radford's bass authority. Strikingly, it replaced a KT120 PP amp with a massively bigger footprint - I would never have expected an EL34 amp to outperform in bass authority and grip a KT120 amp with notionally twice the output power, but better it it did. Design really matters.

[Firebottle]

Design really matters.

Output iron, i.e. the output transformer design (and size) is the key.

[Radford Revival]

I was astonished at the STA25 I'm running at the moment (I'm using it while the Radford STA100 is away being restored). It had 90% of the big Radford's bass authority. Strikingly, it replaced a KT120 PP amp with a massively bigger footprint - I would never have expected an EL34 amp to outperform in bass authority and grip a KT120 amp with notionally twice the output power, but better it it did. Design really matters.

It does indeed, it's (conceptually) easy to build an amplifier that delivers gobs of power, but to do the same thing, especially with valves, is another task. The Radford can be thought of as a fancy Mullard 5-20 with good output transformers.


Output iron, i.e. the output transformer design (and size) is the key.

Indeed, and the conflicting requirements between the low end and high end frequency response design constraints! You have to juggle efficiency, low frequency response, high frequency response, as well as other esoteric parameters that are not immediately obvious

[pgarrish]

It does indeed, it's (conceptually) easy to build an amplifier that delivers gobs of power, but to do the same thing, especially with valves, is another task. The Radford can be thought of as a fancy Mullard 5-20 with good output transformers.



Indeed, and the conflicting requirements between the low end and high end frequency response design constraints! You have to juggle efficiency, low frequency response, high frequency response, as well as other esoteric parameters that are not immediately obvious

As the owner of a pair of Mullard 5-20s with ‘middling’ transformers I’d love to try one of your amps... unfortunately I would then have to give it back.... so I’ll stick with mine for now. They do work very well though

[Radford Revival]

As the owner of a pair of Mullard 5-20s with ‘middling’ transformers I’d love to try one of your amps... unfortunately I would then have to give it back.... so I’ll stick with mine for now. They do work very well though

:D

Just to correct myself, when I said "It does indeed, it's (conceptually) easy to build an amplifier that delivers gobs of power, but to do the same thing, especially with valves, is another task."

I actually meant to say "It does indeed, it's (conceptually) easy to build an amplifier that delivers gobs of power, but to do the same thing with a decent bandwidth, low distortion and good damping factor, especially with valves, is another task."

[Firebottle]

Indeed, and the conflicting requirements between the low end and high end frequency response design constraints! You have to juggle efficiency, low frequency response, high frequency response, as well as other esoteric parameters that are not immediately obvious

That's why you engender :respect: Will.

[farflungstar]

Update. I've just spent an incredibly enjoyable 5 hours of music. Beautiful sonics, pinpoint imaging - from the Carys! The Hiraga needs a bit of attention so I hooked up the Carys but changed the 6sl7 driver from the NOS tung sols I'd been using back to the original Phillips's jobs. Oh my - vocals to die for, a wide and deep soundstage blah blah. Okay this was on mainly female vocals/jazz but it was beautiful. Bass was full and articulate.

This might have something to do with the new Reed arm which is amazing in the mid and top end and very controlled in the bottom end. Maybe the sightly full bottom end of the Cary's balances this out.

Tomorrow I'll try something more demanding.... But it's got me thinking....