6HF5 was the big one for ham radio output stages IIRC . If we could do something with 6GH8 we'd be set for life! RCA TV's used them for about everything.
Don't forget about the vertical deflection types. The 6LR8 comes in the large, nine pin format that has a triode and a beamer in the same bottle. The loadline looks pretty good with a very low H3 estimate, and is nicely away from Class B conditions. The 1K65/phase load translates to 6K6 (P-2-P) and that's a stock, off the shelf, impedance for OPTs, so no custom OPT required.
The triode can be used as a grid driver, saving a bottle. (I have a bunch of these in their 21V heater iteration.)
Another decent TV VD tube is the 10JA5. This one can put out a bit more power. The H3 estimate is somewhat higher, though. The 5K4 (P-2-P) load is also close to stock OPTs.
As for how these sound, that depends on what kind of harmonics they make. If like the HD types that make mainly H3 and little else, just add enough gNFB to take the edge off. If the harmonics are nastier, use local NFB in conjunction with gNFB. You should always listen open loop before finalizing the design.
These look promising, and the odd heater voltages keep 'em available at low cost.
The triode can be used as a grid driver, saving a bottle. (I have a bunch of these in their 21V heater iteration.)
Another decent TV VD tube is the 10JA5. This one can put out a bit more power. The H3 estimate is somewhat higher, though. The 5K4 (P-2-P) load is also close to stock OPTs.
As for how these sound, that depends on what kind of harmonics they make. If like the HD types that make mainly H3 and little else, just add enough gNFB to take the edge off. If the harmonics are nastier, use local NFB in conjunction with gNFB. You should always listen open loop before finalizing the design.
These look promising, and the odd heater voltages keep 'em available at low cost.
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Scavenge hamfests. Atleast that's what I do. Philips made the best ceramic sockets for their 7/9 pin minature and 9 pin magnoval sockets I have ever had my hands on. These can be had for several euro's per box. if you know the right places.
Last time I went to the major yearly swapmeet here I picked up a box whit a couple of E80cc 18 E88CC and more for €10 Aint that a steal
Last time I went to the major yearly swapmeet here I picked up a box whit a couple of E80cc 18 E88CC and more for €10 Aint that a steal
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request granted....
Well...much talk about amplifiers using sweep tubes...not so many that actually made one. I made one for 30 yers ago and its still in duty-...so it must have prone its liability. Its whopping out 85W / 8ohm and even more in 4ohm in the same and only outlet. Plate voltages is only 300V and its UL coupled (50%)...plate impedance 1900ohm. That gives an output impedance on 0,8ohm and a damping factor at 10...before feedback is applied. When..feedback which is only 12db is applyed...then the damping factor increase to 40 which I am very satisfied with. I am aware that PL509/519 are scarce by now...but EL509-JJ is a VERY good replacement and made for audio. I call it *THE FINAL AMP* because I have never wanted any other amplifier. My friends claim the same...
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Ofcourse its needed. we are the DIY community remember!
This sticky was long overdue. Most audio valves have been hyped to a point where some types are not even usefull for new designs as the cost of replacing them in the future would be enormous.
But then again. NOS PL36 can still be had for very little, so why not profit?
This sticky was long overdue. Most audio valves have been hyped to a point where some types are not even usefull for new designs as the cost of replacing them in the future would be enormous.
But then again. NOS PL36 can still be had for very little, so why not profit?
I've got a box full of 12BQ6GTB/12CU6 and 13GB5/XL500 bought off the dollar list. The 12BQ6 are all "El-Menco" brand, made in Farmingdale, NY. The 13GB5's are mostly RCA with a pair of GE and one Admiral. Probably will use these in guitar amps with both high and low gain front ends. Haven't started on one, yet.
I assume that you got these from ESRC?
Elmenco was a manufacturer of capacitors in the 40's and 50's. Somebody began using that name to sell tubes after the cap company went away. They are all relabled tubes from other vendors. I just put together an amp using 6CB5's. They are labled El-Menco but were made by Sylvania.
I got 150 of the 13GB5's from ESRC. They are various brands but they seem to come in three flavors.
One is marked "made in Holland" or "made in the UK" they have a metallic ring painted on the outside of the glass. They are made by Mullard. Your US branded tubes are probably these. They are the strongest ones and I have seen 150 watts flow from a pair!
One is marked "made in Korea" I don't know who made them but they look rather wimpy.
I have seen pictures of tubes that have the letters USA printed just below the 13GB5 number. Thes look like US made Sylvanias.
I believe Matsushita or Hitachi made the 13GB5 but I have never seen one.
Elmenco was a manufacturer of capacitors in the 40's and 50's. Somebody began using that name to sell tubes after the cap company went away. They are all relabled tubes from other vendors. I just put together an amp using 6CB5's. They are labled El-Menco but were made by Sylvania.
I got 150 of the 13GB5's from ESRC. They are various brands but they seem to come in three flavors.
One is marked "made in Holland" or "made in the UK" they have a metallic ring painted on the outside of the glass. They are made by Mullard. Your US branded tubes are probably these. They are the strongest ones and I have seen 150 watts flow from a pair!
One is marked "made in Korea" I don't know who made them but they look rather wimpy.
I have seen pictures of tubes that have the letters USA printed just below the 13GB5 number. Thes look like US made Sylvanias.
I believe Matsushita or Hitachi made the 13GB5 but I have never seen one.
Flopsey & Mopsey
Here are a couple of TV HD types that have some excellent loadlines. These are the 6JM6 and the 6JN6. So what's the difference? Other than one has a plate cap, and the other doesn't, the *JN6 has a somewhat smaller Crt. The plate characteristics are the same. The loadline shows a very low estimate for H3, and these could put out some 50W. The 3K4 (P-2-P) load impedance should come close to stock OPTs.
Might not be so good for screen drive, as the V2k spec is a bit higher, coming in at 220Vdc. For conventional grid drive, however, these could prove quite useful. They also come in some odd heater voltages: 16.8V/0.45A for both types, and 12.6V/0.6A for the 6JN6.
Here, you can select your types and have identical performance for those cases where you'd like to avoid a plate cap.
Both require the duodecar, 12 pin socket.
One possible downside is that this type seems liable to snivets. That means either screen stoppers and/or a positive bias on the beam formers, which are brought out on their own pins, not internally connected to the cathode. Still, a type well worth considering.
Here are a couple of TV HD types that have some excellent loadlines. These are the 6JM6 and the 6JN6. So what's the difference? Other than one has a plate cap, and the other doesn't, the *JN6 has a somewhat smaller Crt. The plate characteristics are the same. The loadline shows a very low estimate for H3, and these could put out some 50W. The 3K4 (P-2-P) load impedance should come close to stock OPTs.
Might not be so good for screen drive, as the V2k spec is a bit higher, coming in at 220Vdc. For conventional grid drive, however, these could prove quite useful. They also come in some odd heater voltages: 16.8V/0.45A for both types, and 12.6V/0.6A for the 6JN6.
Here, you can select your types and have identical performance for those cases where you'd like to avoid a plate cap.
Both require the duodecar, 12 pin socket.
One possible downside is that this type seems liable to snivets. That means either screen stoppers and/or a positive bias on the beam formers, which are brought out on their own pins, not internally connected to the cathode. Still, a type well worth considering.
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Horiz. Outputs:
6JN6, 6JM6, 6GE5, 6GV5, 6DQ6B, 6FW5 (17 Watt) all apparently the same tube except for pinout and capping details. 6GV5 and 12GE5 were available for 1$ for the last two years. A smaller version, the 6GF5 is still available at 1$, (smaller bottle, only 9W, but great for a HV screen or CFB driver at 770V B+ rated)
Then there are the 6HB5, 6GY5, 6JZ6, 16/21KA6, 21JV6, 6KE6 bunch (18 Watt), some of which (odd fil. V) were available at 1$. 16/21GY5 still are $1. These are all very similar spec wize to the 13GB5, but on a compactron base.
6JN6, 6JM6, 6GE5, 6GV5, 6DQ6B, 6FW5 (17 Watt) all apparently the same tube except for pinout and capping details. 6GV5 and 12GE5 were available for 1$ for the last two years. A smaller version, the 6GF5 is still available at 1$, (smaller bottle, only 9W, but great for a HV screen or CFB driver at 770V B+ rated)
Then there are the 6HB5, 6GY5, 6JZ6, 16/21KA6, 21JV6, 6KE6 bunch (18 Watt), some of which (odd fil. V) were available at 1$. 16/21GY5 still are $1. These are all very similar spec wize to the 13GB5, but on a compactron base.
So what's a good candidate for single ended screen drive? I'm itchin' to try something like an EAR 859, but could be something smaller, as power out isn't a big deal. I have some 6BG6GA's and a few other sweep tubes.
Pete Millett's DCPP aka. "Big Red Board" uses them. I'm using 6JM6's in mine, as I have a thing for top caps.
jeff
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For screen drive you need to look at gm2 at equivalent plate currents.
Some cases rated at 80 mA plate current:
6HJ5 2380 (24 Watt tube)
21HB5A 2450 (18 Watt tube)
6DQ5 2573 (24 Watt tube)
6JN6.... 1905 (17 Watt tube)
6JG6A 2440 (17 Watt tube)
6CB5 2158 (26 Watt tube)
6LB6 2845 (30 Watt tube)
6L6 799 (30 Watt tube)
EL34 916 (25 Watt tube)
6LR6 3267 (30 Watt tube)
16/21KA6 2450 (18 Watt tube)
13GB5 1750 (17 Watt tube)
The last two tube types above are still available at $1 each.
Some cases rated at 80 mA plate current:
6HJ5 2380 (24 Watt tube)
21HB5A 2450 (18 Watt tube)
6DQ5 2573 (24 Watt tube)
6JN6.... 1905 (17 Watt tube)
6JG6A 2440 (17 Watt tube)
6CB5 2158 (26 Watt tube)
6LB6 2845 (30 Watt tube)
6L6 799 (30 Watt tube)
EL34 916 (25 Watt tube)
6LR6 3267 (30 Watt tube)
16/21KA6 2450 (18 Watt tube)
13GB5 1750 (17 Watt tube)
The last two tube types above are still available at $1 each.
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Anyone else here a fan of dampers?
When employing all these cool sweeps, do y'all use any 6AF3/6AL3/6AU4/6AX4/6AY3/6BL4/6BS3/6CJ3/6CL3/6CM3/6CK3/6CT3/6DL3/6DM4/6DT4/6DW4/6V3A/etc?
If you study their specs, and compare the output of these to "the usual (full-wave) suspects" on a scope, you can see that they're actually superior to 5V 5-pin rectifiers for power supplies.
I can't be the only one here who's been using these (over conventional octal recs) for years.
They have so many advantages:
First off, you're not limited to FWCT configuration – you can build a half-wave, doubler, or even an all-tube bridge rectifier if you want.
Next, as they're indirectly heated, have 6.3V filaments, and (generally) high h-k voltages, you can use the same trafo winding as your other tubes' heaters – (no need for a separate 5V supply!)
They'll also take a bigger "first cap" (in CLC), and they're dirt cheap.* For instance, you could buy two NOS 6DL3's with sockets and plate caps for less money than a 5Y3GT or GZ34 (and get better performance IMHO).
*(with the possible exception of 6AX4, recently)
Finally (and most important of all), they're super clean – less reverse leakage than any sand rectifier (or FW tube rec), and lower voltage drop than FW recs as well.
I know Lynn Olson is also a big proponent of dampers; I'd like to think he got the idea from me, rather than the other way around.
(Actually, it's probably more like an Alexander Graham Bell/Elisha Gray thing).
P.S.: Lately, I've been really liking the Russian 6Д22С, 6Д20П, and 6Ц19П dampers. (Yeah, plate caps are inconvenient, but their price/performance is worth it).
When employing all these cool sweeps, do y'all use any 6AF3/6AL3/6AU4/6AX4/6AY3/6BL4/6BS3/6CJ3/6CL3/6CM3/6CK3/6CT3/6DL3/6DM4/6DT4/6DW4/6V3A/etc?
If you study their specs, and compare the output of these to "the usual (full-wave) suspects" on a scope, you can see that they're actually superior to 5V 5-pin rectifiers for power supplies.
I can't be the only one here who's been using these (over conventional octal recs) for years.
They have so many advantages:
First off, you're not limited to FWCT configuration – you can build a half-wave, doubler, or even an all-tube bridge rectifier if you want.
Next, as they're indirectly heated, have 6.3V filaments, and (generally) high h-k voltages, you can use the same trafo winding as your other tubes' heaters – (no need for a separate 5V supply!)
They'll also take a bigger "first cap" (in CLC), and they're dirt cheap.* For instance, you could buy two NOS 6DL3's with sockets and plate caps for less money than a 5Y3GT or GZ34 (and get better performance IMHO).
*(with the possible exception of 6AX4, recently)
Finally (and most important of all), they're super clean – less reverse leakage than any sand rectifier (or FW tube rec), and lower voltage drop than FW recs as well.
I know Lynn Olson is also a big proponent of dampers; I'd like to think he got the idea from me, rather than the other way around.
(Actually, it's probably more like an Alexander Graham Bell/Elisha Gray thing).
P.S.: Lately, I've been really liking the Russian 6Д22С, 6Д20П, and 6Ц19П dampers. (Yeah, plate caps are inconvenient, but their price/performance is worth it).