I want to build myself an stereo amplifier with the 5881 tube. Single ended and with ecc88-ish, or 6sl7, or ecc81 as input tubes. Input selector and volumepot in front. Are there someone out there that can give me some good advice. Thanks for a great forum!
This circuit using an EL34 was published on the Angela Instruments site some years ago. If you are using a 5881 - basically a 6L6 variant - you'd likely have change the cathode resistor for a bit less current in the 5881. You could get away with a smaller power supply choke and smaller power trans too. A 5U4 or a 5AR4 would work fine for rectification of you could go with solid state diodes.
Lots of SE circuits out there. Transformers with primary taps available for more power with ultralinear wiring.
S.
Lots of SE circuits out there. Transformers with primary taps available for more power with ultralinear wiring.
S.
Attachments
Thanks, Have a Hammond 370HX transformer I want to use for this project. Have pair of Hammond 125?SE, but I think I will order some 1630 or 1628 instead......The connections on the output transfomer on the Tubelab SE was a little complex/advanced?.
The 370HX HT secondary is perhaps a bit low for tube rectification. SS might be better. I'd say use your existing 125s, try them but leave room on your chassis so you can get the bigger ones later if you wish. The TL SSE OPT setup is to allow a bit of feedback from the secondary to the OP tube cathode if desired.
By "5881" do you mean the Sovtek 5881 (actually a Russian 6P3S-E)? Or do you mean a vintage American 5881 (equivalent to 6L6WGB)?
If you're using the Russian 5881/6P3S-E, it's likely you can copy that Angela SE EL34 design exactly but with a Russian 5881/6P3S-E instead. In my experience using them in push-pull amps, 6P3S-E bias up really close to vintage EL34s.
If you're using a vintage US-made 5881, then that is going to require modification. You may need to raise the value of the "470 TO 500 OHM" cathode resistor to bias the tube where you want it.
I found that the 6P3S-E is a unique tube, roughly equivalent to 6L6 types, but different enough that it's best to think of it as its own thing. It's a beefy one, with max plate dissipation >25W, maybe as high as 30W.
The 6P3S (no "E") is more similar to the old 6L6GA, with max plate voltage 360V, max screen voltage 270V, max plate dissipation 20W. That's one reason why they're so much cheaper than the version with "-E" on the end.
If you're using the Russian 5881/6P3S-E, it's likely you can copy that Angela SE EL34 design exactly but with a Russian 5881/6P3S-E instead. In my experience using them in push-pull amps, 6P3S-E bias up really close to vintage EL34s.
If you're using a vintage US-made 5881, then that is going to require modification. You may need to raise the value of the "470 TO 500 OHM" cathode resistor to bias the tube where you want it.
I found that the 6P3S-E is a unique tube, roughly equivalent to 6L6 types, but different enough that it's best to think of it as its own thing. It's a beefy one, with max plate dissipation >25W, maybe as high as 30W.
The 6P3S (no "E") is more similar to the old 6L6GA, with max plate voltage 360V, max screen voltage 270V, max plate dissipation 20W. That's one reason why they're so much cheaper than the version with "-E" on the end.
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Thanks for the great information. Mine tubes are probably 6P3S, witout E...
https://www.ebay.com/itm/371966740914 Is this not a good tube at all?
https://www.ebay.com/itm/371966740914 Is this not a good tube at all?
The 6P3S is fine, just doesn't have the potential power dissipation and output of the "E" version. With the Hammond 370HX and a tube rectifier you probably won't exceed the max screen voltage. Build it! Have fun!
S.
S.
The circuit that Steve Morley posted in post #2 will probably be great starting point. Your amp's performance is very much a matter of finding a good output transformer. For type 5881, you might be happiest looking for something with a rated primary impedance of 4K Ohms or even 5K Ohms. You'll only be getting peak outputs of a coupla Watts, so peak volume expectations need to be pre-adjusted. Many folks are surprised at how little output they really need.
One thing's for sure: if you build it, and it's safe and Plays Music, you will love it.
All good fortune,
Chris
One thing's for sure: if you build it, and it's safe and Plays Music, you will love it.
All good fortune,
Chris
Here is some 6L6 SE-UL characterization data which may help you decide on an operating point: https://www.cascadetubes.com/optimization-of-the-6l6-se-ul/
Note that the 5881 is electrically equivalent to the 6L6 with increased plate and screen dissipation limits.
Note that the 5881 is electrically equivalent to the 6L6 with increased plate and screen dissipation limits.
6L6, 6L6-G, 6L6-GA, 6L6-GB
Plate 19 Watts 360V. Screen 2.5 Watts 270V.
5881
Plate 23 Watts 360V. Screen 3 Watts 270V.
Plate 23 Watts 500V. Screen 3 Watts 450V (some new ones).
6L6-GC
Plate 30 Watts 500V. Screen 5 Watts 450V.
Your data sheets may vary.
Plug and Play. (usually)
Or
Plug and Pray? (sometimes)
Plate 19 Watts 360V. Screen 2.5 Watts 270V.
5881
Plate 23 Watts 360V. Screen 3 Watts 270V.
Plate 23 Watts 500V. Screen 3 Watts 450V (some new ones).
6L6-GC
Plate 30 Watts 500V. Screen 5 Watts 450V.
Your data sheets may vary.
Plug and Play. (usually)
Or
Plug and Pray? (sometimes)
One PCB to hold it all. Although designed for the KT88 you can use other tubes with the same pin layout.
One caveat: He won't ship outside Europe so you will have to find a freight forwarder. (I used some firm in the UK)
https://www.tubeland.de/product_info.php?products_id=24
One caveat: He won't ship outside Europe so you will have to find a freight forwarder. (I used some firm in the UK)
https://www.tubeland.de/product_info.php?products_id=24
Thanks to you all! Appreciate for all your help, and advice. Great to have you here. Just ordred output transformers and chokes...
Found this schematic on the internet. Low-ish B+ compared to other amps. Have some 6n2p lying in boxes and drawers.
6n2p is similar to a 12AX7 but has a 6 volt filament pins 4 and 5. pin 9 is a shield.
https://frank.pocnet.net/sheets/113/6/6N2P.pdf
https://frank.pocnet.net/sheets/113/6/6N2P.pdf
6A3summer a question for you:
Do you have data on the russian 6P3S-E? I've seen conflicting data and wasn't sure I was interpreting the russian data sheet correctly.
Thx.
Do you have data on the russian 6P3S-E? I've seen conflicting data and wasn't sure I was interpreting the russian data sheet correctly.
Thx.
I have used the 6n2p i several phonoamps with good results. Think I have more than twenty in my boxes.. I have never looked for data for the "E" . I has been a bit confused due to all the different numbers on these . But thanks to all you, for helping me!
