dsavitsk said:
Yes I remember having the same feeling; there seemed to be a gap between 20 and 30 when looking for medium-µ valves. I still have eight of them, but I still have a half-dream of building something again so for now it's "Texas hold 'em". But a minute's Googling found this - they are cheaper than when I bought them five or six years ago. Some of the US dealers might have them - there was a NATO stock number I think.
7N7
Forget the Wish List...
... I'd just be happy if the valve manufacturers started using the original spec's & curves for the valves they make now. Let's face it, the stuff made now doesn't match up to the quality of old. An example would be the workhorse small dual triode, the ECC83.
Nominally, an ECC83 has a gain of 100, and it used to be that valves would be tested before leaving the factory, and those not meeting 95% of rated gain would be discarded. The factory expected a failure rate of about 10% during this test - i.e., 90% of the ecc83's produced met the spec. gain(+/-5%).
Nowadays, you're lucky if the ecc83's produced have a gain of 80. The average from the various sources I've run across, is a gain of between 70 and 75. If you're extremely lucky, you might find 5-10 valves out of a shipment of 1000 that test above 90. The standard has dropped so far that many modern amplifier designs (designed using modern valves as reference) become unstable when fitted with NOS valves - not really a suprise, when they use 5(or more) gain stages to do what would originally have used only 3.
So please, any manufacturers who read this, tighten up your production tolerances, and give us valves that actually match the past specifications. Hell, the majority of users nowadays would probably be happy to pay more for their new valves if they met the original design spec than they are now, paying less for 'non-spec' stuff...
Ho-Hum... just a few thoughts... ymmv... etc...
...G
... I'd just be happy if the valve manufacturers started using the original spec's & curves for the valves they make now. Let's face it, the stuff made now doesn't match up to the quality of old. An example would be the workhorse small dual triode, the ECC83.
Nominally, an ECC83 has a gain of 100, and it used to be that valves would be tested before leaving the factory, and those not meeting 95% of rated gain would be discarded. The factory expected a failure rate of about 10% during this test - i.e., 90% of the ecc83's produced met the spec. gain(+/-5%).
Nowadays, you're lucky if the ecc83's produced have a gain of 80. The average from the various sources I've run across, is a gain of between 70 and 75. If you're extremely lucky, you might find 5-10 valves out of a shipment of 1000 that test above 90. The standard has dropped so far that many modern amplifier designs (designed using modern valves as reference) become unstable when fitted with NOS valves - not really a suprise, when they use 5(or more) gain stages to do what would originally have used only 3.
So please, any manufacturers who read this, tighten up your production tolerances, and give us valves that actually match the past specifications. Hell, the majority of users nowadays would probably be happy to pay more for their new valves if they met the original design spec than they are now, paying less for 'non-spec' stuff...
Ho-Hum... just a few thoughts... ymmv... etc...
...G
There's a fellow selling some 8068's on EBay at the moment -- this is a great tube for someone who's into Electrostatic speakers -- it's used in my Keithley HV power supplies, and the Kepco BHK supplies as well. This tube was harder to get than hen's teeth for a while -- so much so that Kepco came up with a MOSFET solution for their HV supplies -- someone should snatch them up.
http://cgi.ebay.com/Electron-tube-8...ryZ58174QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Electron-tube-8...ryZ58174QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
All the types that I use, and a non-microphonic 6BQ7 would be really nice. 
For new types, there is a distinct lack of power triodes suitable for audio finals. Especially that gap between types like the 45 and the vertical deflection PAs, and the RF triode finals like the 811, 812, 845.
How about a 6AS7 built for audio, with more careful attention paid to section balance? Since this was originally intended for active regulator use, they never paid as much attention to this as they otherwise would have.
"+1 vote for an affordable 45"
mf2 and tubelab said that. The problem isn't cost of production, but rather audiophools who will fork over $400+ a pop for new production. If you can ask and get that, then why sell cheap? (Same goes for 300Bs.)
For new types, there is a distinct lack of power triodes suitable for audio finals. Especially that gap between types like the 45 and the vertical deflection PAs, and the RF triode finals like the 811, 812, 845.
How about a 6AS7 built for audio, with more careful attention paid to section balance? Since this was originally intended for active regulator use, they never paid as much attention to this as they otherwise would have.
"+1 vote for an affordable 45"
mf2 and tubelab said that. The problem isn't cost of production, but rather audiophools who will fork over $400+ a pop for new production. If you can ask and get that, then why sell cheap? (Same goes for 300Bs.)
Miles Prower said:All the types that I use, and a non-microphonic 6BQ7 would be really nice.
For new types, there is a distinct lack of power triodes suitable for audio finals.
Miles youv'e put this home...The 6C33C...I've used "lug ears" and despite matching, I find this beast drifts wildly. The other newly weds are pretty inconsistent and their spec doesn't hold time served operation- esp 845's. My guess is that todays manufacturers couldn't really care a hoot, just market the name up and cash in.
What happend to Vaic VV30B ? >did it ever get into production ?
richj
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.