"The 2001 to 2003 Prius used a 273.6 volt battery pack. The newer ones use a 201.6 volt pack."
That likely explains why I've been seeing big 300V power supplies get bid into orbit lately.
The controller has probably been hacked by someone.
Don
That likely explains why I've been seeing big 300V power supplies get bid into orbit lately.
The controller has probably been hacked by someone.
Don
Slightly OT, but Honda Civic Hybrid 3 times suddenly discharged batteries on the run, then started charging back. The engine was running fine, so I mentioned that all 3 times too late, when it started pulling weak. What may be the cause, is it a common problem?
Interesting schematic, George. The Berning architecture separated out the first gain stage and phase inverter, adding another gain stage after the phase inverter. Berning used cathode followers to drive the screens. Tube complement was 2 X 12AT7, 6SN7 (?) and 2 X 6JN6. I suspect he could use a less rugged follower as he wasn't hitting the screens of his output tubes anywhere near as hard as in your experiments.
I'm thinking of using a JFET differential input stage, cascoded using an 8CG7. This may produce enough voltage swing in its own right to drive the source followers and 17JN6 outputs. If not, I would entertain the option of using a second 8CG7 voltage gain stage. It's nice to find a use for the 8CG7s I've been buying up....
I'm thinking of using a JFET differential input stage, cascoded using an 8CG7. This may produce enough voltage swing in its own right to drive the source followers and 17JN6 outputs. If not, I would entertain the option of using a second 8CG7 voltage gain stage. It's nice to find a use for the 8CG7s I've been buying up....
I have a bag full of those too. Many of them will just plug right into a 6CG7 socket. With the over voltage from most Hammond transformers coupled with todays 122 volt lines, the filament voltage is already over 7 volts.
There are plenty of Toyota hybrid owners working here, but I don't know anyone with a Honda. Likely a software bug. See if the Honda dealer has any software updates for your model.
I come across some Lambda Omega power supplies for CNC machines. Did anybody try them for audio?
They claim good isolation of secondaries from primaries, so I suppose they may be stacked to get all needed voltages.
They claim good isolation of secondaries from primaries, so I suppose they may be stacked to get all needed voltages.
Got home late from work tonight, only had time for some basic knob turning. Most screen drive experts claim best results are found by running the screen at or below zero volts and the control grid at or near zero. I tried this again (with the small 6BQ6's) and got the same bad results. Lots of crossover distortion. So I turned the knobs the other way.
I found a combination that eliminated the unusual distortion curve that I had been seeing. It also eliminated a lot of distortion in general, and affords the amp a very soft clipping characteristic. No feedback of any kind is used.
Details:
Plate voltage 550 volts
Idle screen voltage +80 volts
Idle gontrol grid voltage -19 volts.
Idle current 25 mA per tube.
Power Distortion
0.5W 0.8%
1.0W 0.86%
5.0W 1.14%
10W 1.17%
20W 1.47%
30W 1.74%
40W 1.93%
50W 1.97%
60W 4.03%
70W 6.71%
80W 9.2%
90W 11.25%
100W 15.8%
I found a combination that eliminated the unusual distortion curve that I had been seeing. It also eliminated a lot of distortion in general, and affords the amp a very soft clipping characteristic. No feedback of any kind is used.
Details:
Plate voltage 550 volts
Idle screen voltage +80 volts
Idle gontrol grid voltage -19 volts.
Idle current 25 mA per tube.
Power Distortion
0.5W 0.8%
1.0W 0.86%
5.0W 1.14%
10W 1.17%
20W 1.47%
30W 1.74%
40W 1.93%
50W 1.97%
60W 4.03%
70W 6.71%
80W 9.2%
90W 11.25%
100W 15.8%
Sometimes stacking works, sometimes it leads to a lot of burnt parts. Back In High School Electronics class we had an enormus supply of Eico 0 to 400 volt tube regulated suplies. I would routinly connect several together when I wanted to blow up something big. It usually worked, but I did set a power supply on fire once. In a different experiment, I connected 10 of the 25 volt Sorensens that can be seen in post number 127 (under the scope) this provided enough power (250 volts 5 amps) to create a plasma ball inside a 6AS7G tube.
FWIW, in my 6LF6 amp, I use zero volts g1, but (IIRC) the idle Vg2 is about 10-15 volts and the idle current is much lower (3mA or so). The OL distortion figures look very much like yours except that they don't start rising rapidly until beyond 100W. I suspect the optimums are very tube-dependent and very dependent on plate voltage.
SY, what is your plate to plate load impedance? This amp will be tested with 6LW6's (same guts as 6LF6) eventually.
DaveMcLain said:
There are any number of reasons for that. For the most part, it was simply avoiding the reinvention of the wheel. It's easier to repackage a proven design as opposed to coming up with a new design.
Take the 6L6. This type was one of the first of the beam tubes, designed for use as an audio final. As such, it was bottled in the octal format, and without a plate cap connection since it wasn't intended to operate at very high voltages where flashover at the socket became a problem. When useage as a high efficiency RF amp was requested, it was rebottled as the 807, with a plate cap for more convenient connection to the output circuit, and to stand high plate voltages and higher outputs in Class B or Class C operation. The 807 included the older five pin socket since this is what RF designers were using at the time.
When TV came along, the 807 was rebottled again, this time as the 6BG6 as a horizontal deflection VT. The plate cap was retained for high voltage operation, but the pin-out was changed to the octal format since that's what the TV designers were using. More convenient to repackage the VT as opposed to including that one five pin socket to accommodate an 807.
In another case, the original 50B5 had the same pinout as the 6AQ5. Since this type was designed for series string heater connections and xfmr-less power supplies, the 50C5 came along with a different pinout that moved the plate connection as far away from the heater connections as possible. This being to prevent heater-to-plate flashovers at the socket at power up when the cold heaters were at max volts in the series string. Other than pinout, 50B5s and 50C5s are identical.
The 8068 appears to be a 6BG6 with a bigger plate for more clearance for its HV spec. (still g2/g1 Mu of 8 like 6L6 and 6BG6, and the same g1 gm, if converted to similar current for comparison)
7027 the same as 6L6GC
6GE5 the equiv. 6JN6
6HB5 the equiv. 21JV6
6KM6, 6JG6, 6JF6, 6KV6 nearly the same (have to compare gm's at same currents of course)
6CD6, 6EX6 nearly the same
6JU6, 6JR6
6V11, 6BN11
6AS11, 6AF11
There is an almost endless list of equivalent tubes. (different pinouts or heater voltages of course) A bunch of permutated and identical combos occur in the dissimilar dual triode vertical amp tubes.
Don
7027 the same as 6L6GC
6GE5 the equiv. 6JN6
6HB5 the equiv. 21JV6
6KM6, 6JG6, 6JF6, 6KV6 nearly the same (have to compare gm's at same currents of course)
6CD6, 6EX6 nearly the same
6JU6, 6JR6
6V11, 6BN11
6AS11, 6AF11
There is an almost endless list of equivalent tubes. (different pinouts or heater voltages of course) A bunch of permutated and identical combos occur in the dissimilar dual triode vertical amp tubes.
Don
Ok, I could not resist temptations and bought some tubes for hybrids-on-steroids:
<pre> T-12BQ6GTA-B 12BQ6GTA-B - BEAM POWER AMPLIFIER 26 22.88
T-12C5_12CU5 12C5/12CU5 - TETRODE, BEAM POWER 100 78.00
T-12JN8 12JN8 - TRIODE - PENTODE 20 16.00
T-5964 5964 - TRIODE, DUAL 20 13.00
T-6EU8 6EU8 - TRIODE - PENTODE 50 36.50
T-6U9_ECF201 6U9/ECF201 - TRIODE - PENTODE 20 14.60
T-6X9_ECF200 6X9/ECF200 - TRIODE - PENTODE 12 11.76</pre>
<pre> T-12BQ6GTA-B 12BQ6GTA-B - BEAM POWER AMPLIFIER 26 22.88
T-12C5_12CU5 12C5/12CU5 - TETRODE, BEAM POWER 100 78.00
T-12JN8 12JN8 - TRIODE - PENTODE 20 16.00
T-5964 5964 - TRIODE, DUAL 20 13.00
T-6EU8 6EU8 - TRIODE - PENTODE 50 36.50
T-6U9_ECF201 6U9/ECF201 - TRIODE - PENTODE 20 14.60
T-6X9_ECF200 6X9/ECF200 - TRIODE - PENTODE 12 11.76</pre>
OOPs
That 6V11 above, should have been, 6J11 equiv. to 6BN11
Some audio tubes were duplicated as low microphonic versions.
And then there were the high reliability versions.
That 6V11 above, should have been, 6J11 equiv. to 6BN11
Some audio tubes were duplicated as low microphonic versions.
And then there were the high reliability versions.
Cool, Those monster Plitron OPT's happen to be 1250 ohms, 400 watts at 20 Hz. I guess I should have asked the other obvious question last time. Plate voltage?
I am not so sure about that one. I tried some 8068's in a Simple SE and they behaved nothing like a 6L6GC. They look more like a modern sweep tube. Low screen grid voltage rating is real, glows at 260 volts. This is more typical of a sweep tube. Never did find a happy operating point in SE mode without glowing them. These may work well in P-P, but they are far too expensive to experiment on, especially when there are (were) $2 sweep tubes out there.
Experimenting planned for this weekend is likely cancelled due to the approach of hurricane Ike. The local TV is doing their best to create a panic already. There are already lines at the gas stations and grocery stores. BOHICA!
That number sounded familiar, you probably told me that before, but I am getting forgetful in my old age. Several years ago I made a guitar amp with 6LW6's in G1 drive. It made about 140 watts, and ran on about 750 volts. My bench supply runs out at 550 volts. I guess I need a bigger supply.
"Low screen grid voltage rating is real, glows at 260 volts. This is more typical of a sweep tube."
Ummm, yup, 8068 data sheet says only 1 watt on g2 max, while the 6L6 says 5 watts. Something different there. Electrically though the 8068 g2 gm is the same as the 6L6 g2 gm, giving the same g2/g1 Mu of 8.
Ever tried out the 8417? With so high a g1 gm, it would seem like it should have a frame grid. But the screen grid current is very low, like an aligned grid, so I guess not. Wouldn't mind stumbling onto a box of them for cheap.
Don
Ummm, yup, 8068 data sheet says only 1 watt on g2 max, while the 6L6 says 5 watts. Something different there. Electrically though the 8068 g2 gm is the same as the 6L6 g2 gm, giving the same g2/g1 Mu of 8.
Ever tried out the 8417? With so high a g1 gm, it would seem like it should have a frame grid. But the screen grid current is very low, like an aligned grid, so I guess not. Wouldn't mind stumbling onto a box of them for cheap.
Don
Nope. I tend to avoid high priced tubes, especially if I have to buy them. The 8068's were used in power supplies, hence they can sometimes be found in military surplus. I have collected a few pulls, but I won't abuse them, too expensive. I have never seen an 8417 in surplus, or other low cost sources. Never had one in my hands.
The early 8417's had a reputation for G1 to K shorts. The grid to cathode spacing is very close. Run the tube hot, parts move around, short happens, bias gone, tube melts, amp fries. Not pretty. Another reason not to use them.
So would I. A friend in the surplus business called me today and said that he had found some Tung Sol 6900's, what should he do with them? I reluctantly told him, Ebay. They are far out of my price range.
"I tend to avoid high priced tubes, especially if I have to buy them. "
Me too. Glad you found the 6CB5A's. $2 or $3 is kinda my limit on tube prices. I like the challenge of working with weird tubes anyway. Wait till you see my next amp with 9KC6, 6LE8, and 6CB5A tubes. Someone should start a thread on weird amplifier designs, but would likely degenerate into 5KW xmitting tubes used for a line amp. or something such.
------------------------------------------------
GU50 How much do those go for? And what supplier to order from?
Don
Me too. Glad you found the 6CB5A's. $2 or $3 is kinda my limit on tube prices. I like the challenge of working with weird tubes anyway. Wait till you see my next amp with 9KC6, 6LE8, and 6CB5A tubes. Someone should start a thread on weird amplifier designs, but would likely degenerate into 5KW xmitting tubes used for a line amp. or something such.
------------------------------------------------
GU50 How much do those go for? And what supplier to order from?
Don
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