Hello Drew,
Are you selling? I bought a pair of 26 NOS/NIB from a fella in Auckland just recently. Unfortunately, one from the pair is a dud. I am glad that the seller will replaced it with another once I sent him the proof that the tube in question was very weak.
Please PM me if you are selling. Maybe I can afford the tubes you are thinking of getting rid off.
Abe
Some of the tube prices now days are getting crazy, but it makes sense.
Even though 300Bs are being made today, teh original NOS are going at a big preamium.
Most of these tubes are not in production today and unless someone starts making them the supply will eventually go away.
It's too bad the chinese manufacturers don't seem to be able to compete with 1930 technology at a reasonable price.
Maybe when 26s get expensive enough they will step in.
Until then, expect prices to keep going up.
The big isue I see is the low availabiltiy tubes like 01A, 31, 41, 42, etc that are fun to play with but will probably never have the popularity of the 26, 45, 300B etc, that promotes new production.
Even though 300Bs are being made today, teh original NOS are going at a big preamium.
Most of these tubes are not in production today and unless someone starts making them the supply will eventually go away.
It's too bad the chinese manufacturers don't seem to be able to compete with 1930 technology at a reasonable price.
Maybe when 26s get expensive enough they will step in.
Until then, expect prices to keep going up.
The big isue I see is the low availabiltiy tubes like 01A, 31, 41, 42, etc that are fun to play with but will probably never have the popularity of the 26, 45, 300B etc, that promotes new production.
Some thougths on the use of cathode bias..
Intro:
I just (re)built a '26 preamplifier. It is choke-loaded and C-out. PSU is simple but elegant: RGN1064 (X2, used a half wave), 4.7uF, 10He, 60uF, 560R, 120uF and then per channel apart stabilized using a VR-tube.
Cathodes of both '26 share the same filament psu, in series, so one on +1.5Volt and the other on -1.5Volt, centered at ground. The '26's are battery biased on the grid.
My thoughts:
When using cathode bias, imho the use of ONE filament supply would be no problem (not puristic, I know). since the '26 is biased using the voltage drop on a resistor at 1 amp, this nearly is identically to a battery bias since operating the tube at several mA will not affect the cathode bias..
Ergo, using one filament supply for filaments in parallel increases amperage thus allows for lower filament voltage..
Anybody?
Reason for asking is > just curious < ;-)
..Oh, and a picture of the pre..
Intro:
I just (re)built a '26 preamplifier. It is choke-loaded and C-out. PSU is simple but elegant: RGN1064 (X2, used a half wave), 4.7uF, 10He, 60uF, 560R, 120uF and then per channel apart stabilized using a VR-tube.
Cathodes of both '26 share the same filament psu, in series, so one on +1.5Volt and the other on -1.5Volt, centered at ground. The '26's are battery biased on the grid.
My thoughts:
When using cathode bias, imho the use of ONE filament supply would be no problem (not puristic, I know). since the '26 is biased using the voltage drop on a resistor at 1 amp, this nearly is identically to a battery bias since operating the tube at several mA will not affect the cathode bias..
Ergo, using one filament supply for filaments in parallel increases amperage thus allows for lower filament voltage..
Anybody?
Reason for asking is > just curious < ;-)
..Oh, and a picture of the pre..
Attachments
Congrats very nice buildare you the same person of the website DHTRob?
Errh, yes.. My attempt to share diy-audio experiments and experiences ..
Hi Andy,
Yes, all nasty electrolytics, for starters that is.. First cap however is a Dubilier PIO.. I do not have that much free space in the cabinet to be able to fully MKP the preamp at the same uF..
In some cases it is worthwhile trying to "shield" the '26's. A simple aluminum cage behind and over the '26 will take care of any residual hum caused by stray-fields.. See picture.. Cage must be connected to ground, but will have effect without.
Sometimes it helps as well to cut a piece out of a tin can and wrap it around the valve-base only..
Attachments
What I meant is filament bias, not cathode bias.. sorry..
Some more diy-'26-pron in picture: Mercury HG3 by Electromekano.
