Esoteric Audio Research 516 + photos of the EAR 802 (mm) and EAR "The Preamp" (mm/mc)

[Sonny Beauceron]

Fair enough. I do recall having a TT power supply that blew regularly if I accidentally had left it 'on' at the deck when switching the external unit on. In discussion with the builder, we changed the fuse to a slightly higher rated slow blow, and it never happened again, even when when I made the same mistake. I would take from that that the answer here is most likely just use the uprated fuses. Anything really significant will still cause them to blow.

Makes a lot of sense. Thanks.

 

[Mike Reed]

Many thanks for all that. V helpful. It was a slow blow that blew. I guess I'll order a 1.5 slow just in case that works, but guessing it's going to have to go back to St Neots, which is annoying but I suppose not the end of the world. Thanks again for your helpful advice.

I assume the second one; my first which blew was a slow-blow; it can happen. You may have said, but what rating is your other one? The 509s are scheduled for servicing every 4 years (pre.=6 years) but that has to be dependent on use (and they were designed originally for studio use !)

Two 509s in their inner and outer cases are a cumbersome and heavy load, but all this is organised by Dena (i.r.o. £36 each way). However, you're probably nearer than I am (Norwich) and as UPS almost destroyed my outer box 4 years ago, a trip might be considered now we're out of lockdown. Good luck.

B.t.w., Mark ones or twos?

 

[Yank]

Understand and agree but you were referring to 'cancelling' the pots on turn off (as I do now but didn't previously) whereas I was basing a repeatable situation on NOTHING being moved. Regardless, full deflection makes 100% sense. Can't understand 'the man' advising having the pots about half-way (i.e., 12 o'clock approx. on 180 degree rotation).

Not sure why I turn them off each time, as there's unlikely to be a signal overload. Twin pots may be (and is) a p.i.t.a. on integrated or stereo chassis amps but I can't see how you'd do it otherwise on monoblocks.

Most power amps get around that by not having a level control...

As for why TdP recommended half-way, I suppose that would depend on system matching, how much gain the preamp has vs. the amp's input sensitivity. If the amp was designed with excess gain, attenuating the inputs would counteract that to allow the preamp's volume control to be in its most useful range, and to minimize noise. I've noticed that the British have a long tradition of valve amplifiers with lots of gain - e.g. Leak, Radford, Quad - enough that a passive preamp or unity gain buffer would be ample. American amps are more likely to have 1.25 - 1.5 - 1.75 V input sensitivity to work well with 12 - 20 dB of gain from a preamp.

 

[Sonny Beauceron]

I assume the second one; my first which blew was a slow-blow; it can happen. You may have said, but what rating is your other one? The 509s are scheduled for servicing every 4 years (pre.=6 years) but that has to be dependent on use (and they were designed originally for studio use !)

Two 509s in their inner and outer cases are a cumbersome and heavy load, but all this is organised by Dena (i.r.o. £36 each way). However, you're probably nearer than I am (Norwich) and as UPS almost destroyed my outer box 4 years ago, a trip might be considered now we're out of lockdown. Good luck.

B.t.w., Mark ones or twos?

These are I would guess about 15 year old Mk 2s, last serviced three years ago.

For the last six months or so they've been doing 15 hours a day most weekdays, but as you say, they're supposed to be intended for it (and so have the valve pre and riaa, which are both fine, though less old). And the other one is fine.

Both fuses were identical, 1.25s. I've now ordered a range. I'm going to try 1.6 and 2 and if they both blow take them in.

I'm only 90 mins away, which is good, but I don't drive and my wife doesn't get involved in this kind of thing, which makes it quite a bit more complicated and irritating. But at least it's now possible, so I count myself lucky.

 

[Mike Reed]

For the last six months or so they've been doing 15 hours a day most weekdays,

Gosh! You really use them! Even by fag packet maths that's approaching 2000 hours in 6 months. Doubt I manage 15 hours in a fortnight. Give EAR a ring and chat with an engineer if it still blows fuses; he may be able to point a finger at the likely cause.