The strangest thing- a tale of valve caution.

[sq225917]

So my EAR 509's returned from a service at EAR, all present and correct. A new set of valves were fitted, Tim's Russian sourced ECC83 ECC85 and PL519's. Seeing as I have replacement sets of better valves than Tim's (heresy I know but they are) I thought I'd fit them. This turned put to be a little more complicated than one might initially expect.

To fit the new valves I of course have to remove the valve covers, they are fitted with hidden crosshead phillips No2 screws, and the valve covers are 130mm high. I don't have a 130mm+ No2 screwdriver, neither do Screwfix, or B&Q nor any of the other places I tried. In fact the trouble is that the hole in the valve cover which the screwdriver must pass through isn't actually wide enough to pass the long handled screwdrivers through, and the thinner shafted ones aren't long enough. A quick search on the web finds nowhere stocks them.

When I sent them off for service they were fitted with slotted screws, but the powers that be at EAR swapped them out for crossheads- arses. So I end up taking the Dremmel to the handle of the 125mm thin shaft Phillips No1 driver that I have, I cut away 15mm of plastic handle and it now reaches the captive screw. Of course this doesn't help because the No1 is to shallow to fit the head and spins freely without biting. I then have to take the tip of the driver bit off with the Dremmel to make it fit.

Finally the cover comes off and the better 519's go in first. Naturally i have to bias them, so off comes the bottom. Not wanting to scratch the hell out of everything I screw the feet back in, naturally. I plug it in power it up, and WFT, that last valve is going some shade of red, holy shit, that is reading 11volts instead of 400mv, click, turn it off fast before we achieve meltdown.

Jesus, that was close. I swap the old valve back in to be safe and fire it up again- crap its off again run away thermal meltdown. I hit the switch in time again having caught the bias on the up a lot earlier this time. I'm flummoxed. I have altered nothing, swapped nothing, broken nothing, desoldered nothing, so WTF is up with this thermal run away. I trudge upstairs to the laptop and hit PRINT, out pops the schematic I've been working on, re-labeling all the parts from Tim's original 1979 hand drawn version that is all but illegible.

I then spend several hours after removing the two main pcbs and going over every single component in the amp, they are in within spec, of course they are I've just paid £500 for a bloody service and new valves. I can see no flaws. Now I'm no Tim, or an Anthony, or a Lurcher, hell I'm barely valve amp literate, but i can follow a schematic with 100% accuracy and I do know all the parts in this amp (probably better than Tim does seeing as i've spent 10-20 hours redoing the schematic this past week).

I'm stuck, honestly, utterly lost, what was causing this runaway?

So I reassemble everything, leaving the bottom off of course so I can still measure bias, and just as I'm sliding one of the pcb's back in up to the edge of the casework I'm looking at the feet, the feet that normally bolt through the bottom plate of the amp, which of course isn't in place. The feet that are now 2mm longer than they were before I took the plate off. You've guessed it...

One of them is now sticking 2mm through the back of the casework, where normally it wouldn't stand proud at all and the back of that screw is now making contact with the pcb- and effectively sinking the anode cap of the last 519 valve straight through the casework to ground...

That could have been nasty

Expensive

Or both

[hifi_dave]

Now you know why Tim doesn't like anyone fiddling with his products..:doh:

[simon g]

...and also a lesson for all who might be tempted to 'play' with their amps. If this can happen to someone who clearly has a better than average knowledge of electronics, then lesser mortals should leave well alone. IMO, of course.

[Ali Tait]

Well he wouldn't when he can charge folk £500 for looking at it for them.

[hifi_dave]

EAR's charges are very reasonable, especially when you consider that price included all the tubes.

[Marco]

Lucky escape, Simon! I've had the feet thing happen to me before with a mate's pair of 509s, so I sympathise....

Anyway, now that nightmare is over with, how do your own valves compare to the ones which Tim had in it? :)

Marco.

[sq225917]

Bloody feet man that's an absolute liability, he'd never get that past CE certification these days.

I replaced Tim's valves with my Teslas ecc83's and Ei85's, I left his 519's in place. There's more slam with the Teslas and more sparkle at the top end. The amps aren't completely silent with any of the valves in place, (Tim,'s wiring is way too messy for silence to be on the cards) but with the new set in place the valve noise is reduced and so is the bandwidth of the noise, it's little more than a touch of transformer hum with the Teslas in place and is perfectly acceptable even to a solid state junky like me who is used to absolute silence even ear against the speakers at full volume.

Compared to the Tag125m mono's there's more texture in the mid-low bass from the 509's, but there's also a little bit of a bump in the FR, the TAGs are ruler flat and despite having more power and extension in the bottom end, don't excite my room nodes like the 509's do. In the mid-range it's all for the 509's they are clearer, able to do fine shading with more aplomb and just sound more lively without adversely highlighting any area. Right up at the top I don't think there's anything between them. Overall the 509's are ever so slightly less pneumatic in the bass, but they do render tone better and they have it on small scale dynamics.

I'm going to hang onto them all for a while, let the valves get 50 hours on them and then make a decision on what to do with them. Keep em, or refinish the cases and sell them on to try something else valvey instead. I'd love to hear a decent valve pre, AN M7 or thereabouts fronting a couple of hundred watts of Krell, like an FB300c or similar.

Pop round whenever you like Marco.

[Ali Tait]

EAR's charges are very reasonable, especially when you consider that price included all the tubes.

Where did I say they weren't? I was merely pointing out his financial interest in saying so.

[hifi_dave]

I was merely pointing out that the major part of the cost was the tubes and implying that he charged very little for the service. Tim has no interest in making large amounts of money for service and repairs, he covers his costs.

[Reid Malenfant]

I hope I'm not missing something here, but am I correct in my take on things that a screw that happens to hold part of the chassis together was renewed & a 2mm longer one fitted which caused this problem?

If so I'd suggest contacting the manufacturer before any other amp of anyone elses goes POP! Which it sounds like it might be possible :eek:

Besides which if what I think I might have as being correct I think 2mm of clearance is cutting things a bit fine no? :scratch: Doesn't matter if it is 10V or 200V, any numpty can fit a longer bolt :doh:

[Ali Tait]

Really? For Russian valves? I'd say a tenner or so each for the 519's. Maybe a max of 20. A fiver or so each for the ECC's. No doubt he buys in bulk so gets discounted prices.

[Stratmangler]

Bloody feet man that's an absolute liability, he'd never get that past CE certification these days

He would if he stipulated that his equipment was only to be worked on by accredited engineers.
I find it odd that you should pay someone to service the amps, then take 'em apart and change things :rolleyes:


Tim,'s wiring is way too messy for silence to be on the cards

You're more likely to have noise problems if your amps wiring looks beautiful.

[Marco]

Hi Chris,

On that last point, why? Educate me :)

Regarding the other one, clearly new stock Russian valves aren't the last word in sound quality (at least in my experience they aren't - the NOS ones are different).

Therefore, Simon simply wanted to fit better valves, to optimise the sound, whilst ensuring that the amps had been fully serviced by the manufacturer. Seems perfectly reasonable to me.

Marco.

[Stratmangler]

Hi Chris,

On that last point, why? Educate me :)

Marco.

If your cabling is neatly loomed then you're more likely to have induced crosstalk.
Sometimes it's better to not be so tidy with the wiring.
Obviously, you don't want things to be like a rat's nest, 'cos that makes working on the thing nigh on impossible.....:eyebrows:

[Marco]

Fair enough, and thanks for that.

Obviously I can't argue, as I don't build amps, but both the Croft preamp and TD power amp I own (Anthony is OCD-like in that respect) are immaculately wired throughout and sound superb, with zero 'noise' through the speakers :)

Marco.

[Reid Malenfant]

Chris is right in a certain respect ;) Even in a solid state amp certain wires can be grouped together to preclude the possibility of induced noise, where as other cabling feeding the same semiconductor may well need to have a wide berth.

In the case of stuff that needs to be kept apart it's always best to keep the cables at right angles to each other as well, thus there will be the minimum area of interaction.

[Stratmangler]

I was just taking issue at the implication that the wiring not being the tidiest job was causing noise.
It ain't necessarily so.

[Marco]

Gotcha! :)

Meanwhile, here's an immacculately wired amp, which comes under the 'no noise' category (my copper amp):

http://img580.imageshack.us/img580/5927/insideofthecopperamp.jpg (http://imageshack.us/photo/my-images/580/insideofthecopperamp.jpg/)

:cool:

Marco.

[Reid Malenfant]

Notice how a lot of wires only cross each other ar right angles, where as some do run in the same general direction & close to each other :)

[Marco]

Yesh I see that, daftee... It's probably because the wires that cross each other at right angles aren't friends :D

Marco.

[Reid Malenfant]

Yesh I see that, daftee... It's probably because the wires that cross each other at right angles aren't friends :D

Marco.
Aye, they prefer different drinks :rfl: Some like single malt & others thrive on lager :eyebrows:

Small slurps & big gulps :eyebrows:

[sq225917]

I hope I'm not missing something here, but am I correct in my take on things that a screw that happens to hold part of the chassis together was renewed & a 2mm longer one fitted which caused this problem?

If so I'd suggest contacting the manufacturer before any other amp of anyone elses goes POP! Which it sounds like it might be possible :eek:

Besides which if what I think I might have as being correct I think 2mm of clearance is cutting things a bit fine no? :scratch: Doesn't matter if it is 10V or 200V, any numpty can fit a longer bolt :doh:

You haven't missed anything, but you have made up a bit where I swapped bolts. I merely removed the bottom cover (to retain access to the bias pots for trimming) and refitted the feet, which then screwed the depth of the removed cover closer to the pcb- kapow.

There's certainly little rhyme or reason in a lot of the wiring in the 509's there's not really any 90 degree crossovers. More of a rats nest.

I'll trace the wires out tomorrow to see if there's any signal/HT foobars going on.

I did notice that the input sensitivity of the 509's is rated at 1.6v, I had my Weiss set for a maximum output of 1.2v, so I've now set that to 2.2v and wound the pots on the 509's back to about half- halving the noise at my speakers but keeping output volume the same. I never run the Weiss wide open at 0db, my max -18db measures up at near enough bang on 1.6v pp.

Result.

[jandl100]

When I had my old EAR 509/ii amps serviced the engineer nodded wisely and said you had to watch the screw lengths and make sure the right screws go back in, as one was deliberately shorter than the rest and you could get electrocuted if you didn't get the short screw in the correct hole.

Honest, that's true.

[DSJR]

HiFi dave has a tale to tell about a brand new pair of 509's he once got out for dem.. The thing is, once they've been tested and found to be working, they'll stay that way for decades :D

By the way Marco, your copper amp appears to have the signal wires running up the sides of the cases as far away as possible from the power lines, which seem to run up and across the middle. The speaker terminals are as close as feasibly possible to the output transformers. All good practice to me as an "enthusiastic amateur observer..." I wish I'd taken a shot or two of the interior of my Croft OTL, as, stability aside, the internal construction was amazing I thought.

[sq225917]

I had noticed one screw was about 1mm shorter than the rest, it has been placed accordingly. Frankly though an effin liability given the requirement to remove the bottom cover to bias em.

They are however sounding bloody lovely this morning.

[goraman]

I have been following this, glad you got it sorted out.
I'm glad my Manley labe bias pots are on the top of the amp.
Wow! what a pain in the arse you went through!

[sq225917]

Yeh, no one said it would be painless.

[DSJR]

Am I right in saying the current 509's have the bias adjustments more easily accessible?

Regarding feet, it used to be possible to get nylon/plastic screws, which would forever answer the safety issues I think...

Still, a total spend of around £1500? is still a great price I reckon. I still feel a bit guilty for buying an alternative now way back when, especially as the alternative only sounded fantastic for a year or so before the output valves wore out. No chance of that with 509's, which were "only" £2500 the pair in 1989 or so..

[hifi_dave]

For 25 years or more, the EAR 509 has had the bias pots accessible from the top and balance is achieved by a row of LED's. These are the previous model.

[sq225917]

These are indeed the original models and they do stand me at about £1600 inc posh valves. Most acceptable. In fact that sound bloody lovely with the new Kuzma.

[tubehunter]

yes marco, i remember finding the same fault with the feet on ian's pair of 509's.
i thought it was a one off but looks like a common problem.
pretty poor design mistake.

[pure sound]

Meanwhile, here's an immacculately wired amp, which comes under the 'no noise' category (my copper amp):

http://img580.imageshack.us/img580/5927/insideofthecopperamp.jpg (http://imageshack.us/photo/my-images/580/insideofthecopperamp.jpg/)

:cool:

Marco.

It is neatly done, (Nice work Anthony) but I don't think the mains inlet wiring would pass muster with CE inspectors. Not that it needs to, this being more a bespoke one off rather than a commercial product.


(should be a boot over the inlet socket & double insulated wiring to the on/off switch (is there one?) and transformer if memory serves.)

[Marco]

Indeed, Duncan... Ol' Timmy Boy needs his botty spanked! :spank:

Guy, thanks for your comments, and noted. However, it sounds bloody amazing, so that's all I'm arsed about!! :eyebrows: ;)

Marco.

[sq225917]

All incoming mains must be sleeved up to the transformer primary in 1kv rated sleeving on top of Guy's comments. Had to do all that when building those supplies for the Young dac a while back.

[Marco]

In normal circumstances, yes. But remember that there are only 5 copper amps in existence, all of which but one were built 15+ years ago, and probably unlikely to be any more...

Proper hard-wiring, though, is so much better than PCBs. Every time I listen to a valve amp that uses PCBs, I can hear their detrimental sonic effect.

Marco.

[pure sound]

I'm inclined to agree with regard to valve amps but do bear in mind that almost every CD player has them and most recordings you hear (certainly from the 60's onwards) will have traversed many printed circuit boards before even reaching your TT or CDP.

[DSJR]

Oh yes, and hundreds of IC op-amps too... Amaing that any music at all came out the other end :D

Seriously though, to see labours of love such as the Copper amps - and much of Glenn's work too (and I know there are other very worthy hand built models out there) is a real joy and a pleasure to behold and use.

By the way Marco, regarding circuit boards - I don't think they're an issue as long as the track is substantial enough to take the current and as long as the soldering is to a high standard and the track is laid out with some thought and care. It could be argued in the past I think, that the quality of component legs may not have been as good as a decent copper track, but of course, I'm in no way able to substantiate the comment :)

Anyway, I know that your particular copper amp will probably be a lifelong partnership with you in any case :)

[sq225917]

let's be honest hard wired is fine for amps, but for circuits operating at RF, it would just NEVER work.

[NRG]

They managed quite well in the 1930s without PCBs ;)

http://www.radioblvd.com/1937Station.html

[sq225917]

Yes but you did need a warehouse to accommodate what would fit in a matchbox today. ;-)

[Marco]

Seriously though, to see labours of love such as the Copper amps - and much of Glenn's work too (and I know there are other very worthy hand built models out there) is a real joy and a pleasure to behold and use.


Indeed, which is one of the reasons why I use both Croft and Tube Distinctions amps, which are all totally hard-wired, without a PCB in sight! ;)


By the way Marco, regarding circuit boards - I don't think they're an issue as long as the track is substantial enough to take the current and as long as the soldering is to a high standard and the track is laid out with some thought and care.


Sure, but that's quite expensive to do, and IMO, still not as sonically good as hard-wiring with some quality thick cable, provided you know what you're doing!

For me, hard-wired amps always sound more natural, alive and open, than their PCB-fitted counterparts.


Anyway, I know that your particular copper amp will probably be a lifelong partnership with you in any case :)

Indeed - it's going nowhere, as pretty much nothing is in my system now. I love it all to bits! :cool:

Marco.