Page 1 of 1
Low-noise preamp valves? (ECC83/12AX7)
Posted: Fri May 11, 2012 11:43 am
by 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?
Posted: Fri May 11, 2012 1:08 pm
by 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.
Posted: Fri May 11, 2012 2:41 pm
by batsbrew
Posted: Fri May 11, 2012 2:57 pm
by NickS
Looks like they have a heat-shrunk wrapper that stops the glass from ringing?
Posted: Fri May 11, 2012 5:44 pm
by 71Smallbox
NickS wrote:
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.
Posted: Fri May 11, 2012 10:33 pm
by 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.
Posted: Fri May 11, 2012 10:34 pm
by batsbrew
Looks like they have a heat-shrunk wrapper that stops the glass from ringing?
that's a negatory.
Posted: Sat May 12, 2012 10:54 pm
by NickS
UlricvonCatalyst wrote: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.
Posted: Sat May 12, 2012 10:55 pm
by NickS
batsbrew wrote: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?
Posted: Sun May 13, 2012 8:16 am
by 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.
Posted: Sun May 13, 2012 1:28 pm
by batsbrew
Posted: Sun May 13, 2012 6:19 pm
by NickS
NickS wrote:So what is the function of the jacket?
Posted: Sun May 13, 2012 7:09 pm
by paul_
Keep guessing!
I reckon it's in loving memoriam of all the tubes that have failed before it.
Posted: Mon May 14, 2012 8:17 am
by UlricvonCatalyst
UlricvonCatalyst wrote: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.
