Hi.
I have found some old tubes:
2 of 12ax7/ecc83 (brimar and mulled 70''s era)
2 ecc88
2 ecl83
Now I am aware that the first on the list are commonly used for input stages of guitar amplifiers amongst other things.
I am also aware that the others are UHF types (or at least one of them is)
But can they be turned to AF use?
Can anyone offer any advice/links to projects using these tubes?
Many thanks in advance for any help you folks can give an SS guy like me.
I have found some old tubes:
2 of 12ax7/ecc83 (brimar and mulled 70''s era)
2 ecc88
2 ecl83
Now I am aware that the first on the list are commonly used for input stages of guitar amplifiers amongst other things.
I am also aware that the others are UHF types (or at least one of them is)
But can they be turned to AF use?
Can anyone offer any advice/links to projects using these tubes?
Many thanks in advance for any help you folks can give an SS guy like me.
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ECC88 was used in UHF tuners as mixer/oscillator. ECL83 was a lower power version of the ECL82 for record players (Dansette etc) and ECC83 you know about.
ECC 83, Tube ECC83; Röhre ECC 83 ID411, Double Triode
ECC 88, Tube ECC88; Röhre ECC 88 ID2488, Double Triode
ECL 83, Tube ECL83; Röhre ECL 83 ID20283, Triode-Pentode
ECC 83, Tube ECC83; Röhre ECC 83 ID411, Double Triode
ECC 88, Tube ECC88; Röhre ECC 88 ID2488, Double Triode
ECL 83, Tube ECL83; Röhre ECL 83 ID20283, Triode-Pentode
Im hoping to build a small simple amplifier, likely a couple of watts, just enough for a small speaker. Mainly just for kicks. I may also have a couple of transformers, though once ive removed them ill know more about them (I suspect one is for the B+ but the others may be useless (I salvaged these partd from old instrumentatiom so any OPT is likely very low rating.
Thanks Jon,
I will check those links out when I get back to my desktop-I have some info from the valve museum but I'm sure it lacks app ccts, like so many IC datasets possess.
I'm currently trawling second hand bookshops for valve books to help me out.
Ball pencil,
Yes I agree that it's a dumb question (currently reading the mullard SS amplifier book and trying to find equivalents for the old AC*** output transistors (bc547, bd139 and 2n3055 look like likely candidates )
Thanks Jon,
I will check those links out when I get back to my desktop-I have some info from the valve museum but I'm sure it lacks app ccts, like so many IC datasets possess.
I'm currently trawling second hand bookshops for valve books to help me out.
Ball pencil,
Yes I agree that it's a dumb question (currently reading the mullard SS amplifier book and trying to find equivalents for the old AC*** output transistors (bc547, bd139 and 2n3055 look like likely candidates )
Thanks Tom,
In the limited time I have had so far, I have compared the ecc83 and ecc88, and my conclusions were similar (although I'm still a beginner ).
The ecc83 being old stock brimar and mullard brands are likely to get tested in the V1 position in my guitar head amplifier (perhaps, assuming they have life left in them, they may be comparable to the GE tubes that are currently in place). If there is really all that much perceived difference between these 70s era tubes and the 80s GE types.
Besides that I have read the ecc83 isn't particularly linear, and a bit weedy for a driver stage, so I was hoping the ecc88 was an improvement in both areas.
I'm not sure I really have a use for the ecf80, and i dont think i will need the gain of athe pentode half, so I may sell these on cheap, with the caveat that I don't know if they are functional (filaments are ok but that's all I can tell)
Thanks all for the help so far.
I think I might be catching the 'bug'
In the limited time I have had so far, I have compared the ecc83 and ecc88, and my conclusions were similar (although I'm still a beginner ).
The ecc83 being old stock brimar and mullard brands are likely to get tested in the V1 position in my guitar head amplifier (perhaps, assuming they have life left in them, they may be comparable to the GE tubes that are currently in place). If there is really all that much perceived difference between these 70s era tubes and the 80s GE types.
Besides that I have read the ecc83 isn't particularly linear, and a bit weedy for a driver stage, so I was hoping the ecc88 was an improvement in both areas.
I'm not sure I really have a use for the ecf80, and i dont think i will need the gain of athe pentode half, so I may sell these on cheap, with the caveat that I don't know if they are functional (filaments are ok but that's all I can tell)
Thanks all for the help so far.
I think I might be catching the 'bug'
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If that were the case, then the literally hundreds of different phono stages made over the last 50 years must all sound rather poor, which is unlikely if the tube wasn't linear. Have a look at the curves on the data sheet:
http://www.mif.pg.gda.pl/homepages/frank/sheets/093/1/12AX7A.pdf
jeff
Too many options!!!
This idea to use these salvaged tubes was spawned by my desire to build a small ~10W amplifier (stereo would be nice but I'm taking baby steps).
To this end I have several options, mostly SS, but I've not built a tube amp before and it has a certain appeal.
1/ TDA2004 amplifier (I have loads of chip amps already lol )
2/ something discrete with the help of the mullard transistor audio amplifier book I was recently gifted.
3/ a tube amplifier using these salvaged tubes, and a couple of salvaged 6L6GC I also have laying around.
I like option 3 most at the moment, in all ways except the necessity for Iron!
I'd really like to use the mazda 1505 one day, when I can build enough stages to drive it!
This idea to use these salvaged tubes was spawned by my desire to build a small ~10W amplifier (stereo would be nice but I'm taking baby steps).
To this end I have several options, mostly SS, but I've not built a tube amp before and it has a certain appeal.
1/ TDA2004 amplifier (I have loads of chip amps already lol )
2/ something discrete with the help of the mullard transistor audio amplifier book I was recently gifted.
3/ a tube amplifier using these salvaged tubes, and a couple of salvaged 6L6GC I also have laying around.
I like option 3 most at the moment, in all ways except the necessity for Iron!
I'd really like to use the mazda 1505 one day, when I can build enough stages to drive it!
It's not that ECC88 is somehow 'better' than ECC83. They're both good (or bad) in different ways.
ECC88 has a lower plate resistance, lower gain, runs at higher current.
ECC88 has a much higher plate resistance, high gain, runs at very low current for a vacuum tube.
ECF80 is a combination triode-pentode in one envelope. That can be used for quite a lot of different projects too. Maybe even an RIAA preamp. The triode looks like it has a plate resistance of about 4k ohms, amplification factor of about 20, transconductance of about 5mA/V. That's not all that far from ECC88, come to think of it. The pentode part looks like it could be fun to work with. It would make a reasonable input voltage amp and phase splitter for a push-pull amplifier with 6L6 outputs.
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ECC88 has a lower plate resistance, lower gain, runs at higher current.
ECC88 has a much higher plate resistance, high gain, runs at very low current for a vacuum tube.
ECF80 is a combination triode-pentode in one envelope. That can be used for quite a lot of different projects too. Maybe even an RIAA preamp. The triode looks like it has a plate resistance of about 4k ohms, amplification factor of about 20, transconductance of about 5mA/V. That's not all that far from ECC88, come to think of it. The pentode part looks like it could be fun to work with. It would make a reasonable input voltage amp and phase splitter for a push-pull amplifier with 6L6 outputs.
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EL37s are indeed in high demand on eBay. Well worth selling and using the money to buy more viable valves.
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