advertisement


valve amp reliability

B

Brian S

pfm Member
Thinking in terms of reliability and access to swift repairs, does it make sense to buy British made amps rather than European or American? Any advice around this issue?

Thanks for response.
 
I'll presume we are talking valve power amps/integrated amps rather than pre amps/phono stages... They vary widely in reliability but are not as reliable as solid state amps. They are generally considerably easier to repair than solid state amps though and there are plenty of people offering repairs (including me:D). It is certainly possible for a valve amp to be used for an hour a day for 5 years+ without any issues, but on the other hand it is not unheard of for one to need attention of some sort every 6 months to a year..
Failure of output valves will be your main concern reliability wise...(followed by rectifier valves on vintage amps or those modern amps silly enough to use them) and I would say around 60-70% of issues will be with the output valves typically. Modern valves are not as reliable as the ones from the 50's and 60's but are much better than they were in around 1990. Output valve failure can cause some "collateral damage" to surrounding parts but unless you are really unlucky and an output transformer fails it's usually straightforward to fix. Valves other than the output valves are under far less stress and run much cooler and so tend to be much more reliable and long lasting than output valves.
 
I think the main thing is ,if you're thinking of buying a valve amplifier then get the best one you can afford ,steer clear of anything cheap ,poor quality output transformers forget it .
 
If you buy from a dealer who can't then support you...???
If you buy used, then yes, it makes sense to be cautious and buy from a good company like Puresound, who will do all they can to help.
But why worry? IME they are fine generally and although you need to be happy to tinker with valves very occasionally, mostly you just plug and play.
 
I've got a valve amp, a valve Phono stage & a valve dac. Overall, years of valve ownership & NO reliability issues whatsoever. (Now thats tempting fate, isn't it.)
OK, roll some different valves in for fun, rather than having to do so for reliability reasons every few years.
But then a multi-box Naim system supposedly benefits from re-capping every 10 years or so & that costs a whole lot more than a few valves.
 
I've had an Icon Audio Stereo 40 mk111 for almost 4 years, and haven't even needed to adjust the bias on the valves yet. It's a heavy beast to courier if it ever needs to go back to Icon in Leicester, but I'm confident that I could get it repaired in future.
 
I use American made valve phono stage and pre-amp and an American made hybrid power amp (6SN7 tubes followed by solid state stage) and have had no issues.

However I did have a SAC (Thailand) valve power amp (the one HFW raved about) actually catch fire when a power valve failed... needless to say there was no backup of any sort from the manufacturer (I could not locate an importer) and the thing was a complete write off.

So yes, reputable Western is probably a safer buy than stuff from further afield unless you can afford the likes of AirTight and similar.
 
i have an american valve amp , i have had superb service from the UK repair agent [modwright] as long as there is back-up in uk then i would not worry . i have just declined a fabulous valve amp of epic proportions as it has to go overseas for repair. that also applies to another make of ss amp . the after market support is critical .
 
I run a self-restored Leak Stereo 20. It dates from 1961, and whilst I no longer use them, its original Mullard GZ34 rectifier and two of the Mullard ECC83s are still working fine. Proper Mullard GZ34s can last a lifetime, they are famously reliable. I’ve replaced the whole tube-set with NOS just to bring its lifespan back to ‘as new’ from the point I rebuilt it. I’m running Russian military 6P14P-ER output valves which have a 10,000 hour lifespan and alternating between two active sets for hopefully a very long time before failure. The small ECCxx signal tubes have a very long life too (or do if you buy decent NOS) and it is not uncommon at all to find classic amps such as Quad, Leak, Radford, McIntosh etc with many of their original valves from the 1960s in serviceable condition. A sensible rebuild with fresh capacitors, replacement of any out of spec resistors and a good fresh set of valves should have them working very reliably indeed.

Much of the negativity towards valve amps is down to the rash of cheap modern Chinese amps that tend to be designed for 220v mains and are working beyond their margins on UK voltage, plus they are often very cheaply specified. There are many stories of them blowing up. The vintage classics need rebuilding correctly in order to return them to original function. There are many hopelessly botched/tweaked and to my mind ruined examples knocking around so buyer beware! Some botched piece of crap failing does not imply that type of amp in original specification is unreliable. Quad, Leak, Radford etc knew exactly what they were doing and they made reliable kit. So good and reliable it is still in demand half a century or more later!
 
This site contains affiliate links for which pink fish media may be compensated.
hifinutt said:
i have an american valve amp , i have had superb service from the UK repair agent [modwright] as long as there is back-up in uk then i would not worry . i have just declined a fabulous valve amp of epic proportions as it has to go overseas for repair. that also applies to another make of ss amp . the after market support is critical .
Click to expand...

Probably not. I could probably have repaired them no problem (other repair services are available:D) as could any good engineer.

It never ceases to amaze me the way many seem to think only the manufacturer or someone who once worked for the manufacturer can repair things successfully, but it simply isn't true. The only time that yes, "only the manufacturer can fix it" is true is in those small number of cases where a part specific to that manufacturer is needed and they won't sell the part to an independent repairer. In a typical valve power amp this would mean only the output transformer and maybe the mains transformer. All other parts are generic generally.
 
I have owned two valve integrated amps one a Mingda and an Emile. Both ended up with power supply issues. I may have been unlucky but I am now sticking to SS.
 
Like I said the valves themselves are virtually the whole story when it comes to valve amp reliability and even then it is the output valves and rectifiers which cause 90% of the problems.
I have a Leak Stereo 20 and with the wrong valves it can be spectacularly unreliable, as can any other valve power amp. With Mullards or the equally good Brimar, Mazda, Marconi, Tungsram etc they are reliable in general but there will still be a random valve failure here and there.
I well recall Pinnacle and Edicron branded valves from the 80's and early 90's which were incredibly unreliable! Often they would blow spectacularly with internal fireworks show for free the first time the amp was switched on and as it warmed up into operation.
I have an Edicron GZ34 in my St20 at the moment which was one of 5 NOS 80's ones I was given by a mate.. the other 4 blew, 2 as it warmed up and the other 2 after about 5 hours use. The 5th has been reliable so far for a couple of years. A Mullard or similar NOS GZ34 tends to be very reliable.

Any vintage valve amp will need a complete rebuild, usually even to work at all and certainly if they are to be reliable and give their full performance. Electrically leaky coupling caps are the number1 problem and if an old amp like a St20 is powered up before a rebuild you will generally get loads of mains hum and the valves will glow red in places they ain't supposed to.. before failing altogether... ouch if they were good NOS ones! The transformers will be under great stress under these conditions as well.

They can be rebuilt to be far better than they were when new as we have access to much better components today.
 
Arkless Electronics said:
Probably not. I could probably have repaired them no problem (other repair services are available:D) as could any good engineer.

It never ceases to amaze me the way many seem to think only the manufacturer or someone who once worked for the manufacturer can repair things successfully, but it simply isn't true. The only time that yes, "only the manufacturer can fix it" is true is in those small number of cases where a part specific to that manufacturer is needed and they won't sell the part to an independent repairer. In a typical valve power amp this would mean only the output transformer and maybe the mains transformer. All other parts are generic generally.
Click to expand...

ah i have every confidence jez that you could repair this amp but as it would be under warrenty i think it might invalidate the warrenty perhaps
 
Rodrat said:
I have owned two valve integrated amps one a Mingda and an Emile. Both ended up with power supply issues. I may have been unlucky but I am now sticking to SS.
Click to expand...

Ming Da used to be terribly unreliable as they were grey imports via eBay for 220v mains so cooked quite quickly on UK 240v. I think they are now imported properly so likely have adequate mains transformers now! The internet was certainly awash with stories of smoking Ming Da amps at one point, in fact Lordsummit had one! I’ve never heard of Emile, is that far eastern too?
 
I’ve had my SC22/STA15 serviced after literally twenty years without use. All that needed to be replaced was one electrolytic, two resistors and an EL34 (fortunately I had a spare Mullard.) Oh, and a bunch of brittle tag board to valve socket wires. It is sounding great and now performing way, way inside the Radford spec.
 
I've been running a couple of French integrated valve amps (Jadis), a Brtish valve phono stage (EAR) and a Chinese valve CD/DAC (Shanling) for the best part of ten years. Exactly as Arkless suggests, the only problem I've had is with a couple of duff power tubes and associated fuses failing. Fortunately no harm was done and I now avoid Chinese tubes like the plague. I stick to current production Russian output tubes.
 
Another thing to remember is that amps with manual biasing will need the bias checking occasionally as the output tubes age and/or when they are changed. This can be a bit of a faff with some amps and, depending on your knowledge and competence, you may need to take it to a technician to have it checked and adjusted. No such problem with autobias.
 
You must log in or register to reply here.


advertisement


Back
Top