Wtd.. Matched quad of 6LS7 Tubes

[Alfonzo]

Hi guys Looking a matched quad of nice 6SL7 tubes for my headphone amp. I require the short bottle versions of these tubes.

WHY


sorry mods please can you change Title to 6SL7 tubes wanted

[Lawrence001]

I have to say I've never seen a matched quad of NOS 6SL7s so you'll probably need to buy new. If you're lucky someone on here will have a little used set.

[Alfonzo]

A lightly used quad would do too thanks or even a matched pair would do at a pinch

[Lawrence001]

You could always buy some cheap Russkies and match them by ear..

https://rover.ebay.com/rover/0/0/0?m...2F273944999504

[vintagesteve]

I'm sure a lot of people realise this, (and I'm sure there are some that don't!) but a so called 'matched pair' or a 'matched quad' of valves is not ones that are of the same make and era and in the same manufacturer's boxes. I have seen so many sets of four Mullard EL34s being sold as a 'matched quad' when in fact they are just same era, same box, valves. When questioned about how they had been matched, the sellers' replies exposed that they didn't know what 'matched valves' were - or maybe they did but were trying to bluff a higher price for the four. Matched valves are matched using a valve tester to match two key parameters, these being anode current and mutual conductance. But you really can't match them by ear, you may just as well use unmatched ones if they're not guaranteed electronically matched.

[Lawrence001]

My point was that if you plug 4 in and the sound is balanced between the channels (in sound quality/tonality as well as volume level) then in practical terms they are a close enough match. If not switch them around in a logical manner until you find a quad that are close enough to sound audibly the same.

When I've bought "matched" pairs the numbers quoted are never identical, they are "close" but I have no idea what values are close enough to make them sound the same, or even whether the audible effect of differences is linear, quadratic, exponential or whatever. Nor what units I am measuring sonic closeness in anyway. It probably depends on a multitude of factors including the circuit, the system, the speakers, the room and my ears. If they sound the same (and good!) then it's good enough for me.

[Audio Al]

Try Anthony at TD

https://tubedistinctions.co.uk

[Alfonzo]

Thanks for the heads up Al

Try Anthony at TD

https://tubedistinctions.co.uk

[Alfonzo]

Now Sorted