Low-noise preamp valves? (ECC83/12AX7)

[NickS]

Anyone got a recommendation? There are some oldish reviews hanging around but nothing recent, but if anyone can tell me what ECC83/12AX7 offers good lack-of-bang-and-hiss per quid from Hotroxuk.com or Watford for V1, that would be good. Anyone tried the Harma (specially-selected) versions and reckon they're worth it?

[UlricvonCatalyst]

I read an interesting post on NOS vs. new valves over at a certain forum renowned for its cork-sniffers which actually made a lot of sense in terms of how valves were made then as opposed to now. One of its conclusions was that even 'used' old valves stand a better chance of being better than a new one and can often be had for less money.

Bearing that in mind, you can't go wrong with an old Mullard - try and find a NOS or 'used, tests new/100%' rebranded Mullard, such as Philips or Mazda (the giveaway is that all the Mullard-made ones will have a google-able code etched around the bottom) and try searching some of the less common aliases for ECC83/12AX7 such as CV4004 or 5751.

Old Dansette-type record players can be a good source of vintage ECC83s, but unless you can look inside before you buy it's pot luck.

[batsbrew]

try a mesa spax7

http://www.humbuckermusic.com/mespprgrprtu.html

these are really nice

[NickS]

try a mesa spax7

http://www.humbuckermusic.com/mespprgrprtu.html

these are really nice

Looks like they have a heat-shrunk wrapper that stops the glass from ringing?

[71Smallbox]

try a mesa spax7

http://www.humbuckermusic.com/mespprgrprtu.html

these are really nice

Looks like they have a heat-shrunk wrapper that stops the glass from ringing?

That looks like an bad idea, if a brand of tubes have a tendency to be microphonic from poor construction, a silicone jacket won't resolve that issue as its caused by internal vibration of the tubes parts! All of the chinese 12ax7's I've had have been shite, maybe get some Sovtek, RFT's or seek out some 80's era Sylvania/GE 12ax7wa with better construction. I would avoid JJ ECC83s or any ruby tube offering and the Groove tubes.

[batsbrew]

these are hand selected for superior microphonics

read up on them more, that's probably your best bet or another mfg of a similar model.

[batsbrew]

Looks like they have a heat-shrunk wrapper that stops the glass from ringing?

that's a negatory.

[NickS]

I read an interesting post on NOS vs. new valves over at a certain forum renowned for its cork-sniffers which actually made a lot of sense in terms of how valves were made then as opposed to now. One of its conclusions was that even 'used' old valves stand a better chance of being better than a new one and can often be had for less money.

Bearing that in mind, you can't go wrong with an old Mullard - try and find a NOS or 'used, tests new/100%' rebranded Mullard, such as Philips or Mazda (the giveaway is that all the Mullard-made ones will have a google-able code etched around the bottom) and try searching some of the less common aliases for ECC83/12AX7 such as CV4004 or 5751.

Maybe I'll pull some old Mullards out of my Copicat Mk. 1 and see how they are.

[NickS]

Looks like they have a heat-shrunk wrapper that stops the glass from ringing?

that's a negatory.

So what is the function of the jacket?

[UlricvonCatalyst]

I think those things are a variation of the aluminium sleeves you sometimes see around valves. Can't imagine they offer much protection, but at least they'd keep the valve more-or-less intact if it cracks or something.

[batsbrew]

IT's not an aluminum sleeve





best used in position V1
http://mesa.stores.yahoo.net/spax7.html

http://www.sweetwater.com/store/detail/MBSPAX7

[NickS]

So what is the function of the jacket?

[paul_]

Keep guessing!

I reckon it's in loving memoriam of all the tubes that have failed before it.

[UlricvonCatalyst]

I think those things are a variation of the aluminium sleeves you sometimes see around valves.

My guess is it's to prevent Mesa buyers seeing clearly what they get for their money.