are you serious? i suppose i can give you the contact info of the vendor and you deal with them direct. only i do not know if they export these tubes, all i know is that they are old stock.
btw, the 3dg4 has a piv rating of 1000volts but plate to plate of only 500volts. i suppose if i make this a single diode, then i have a 1kv, 0.7amp rectifier, am i correct? a pair would make a nice rect in a hybrid psu.
i assure you that i have enough high voltage expeirence, i do construction work for oils and gas plants as construction supervisor. we build electrical substations where voltages are 6.6kv primary and 440volts secondary. i have a healthy respect for high bvoltages as i am aware of the hazards involved.
btw, the 3dg4 has a piv rating of 1000volts but plate to plate of only 500volts. i suppose if i make this a single diode, then i have a 1kv, 0.7amp rectifier, am i correct? a pair would make a nice rect in a hybrid psu.
i assure you that i have enough high voltage expeirence, i do construction work for oils and gas plants as construction supervisor. we build electrical substations where voltages are 6.6kv primary and 440volts secondary. i have a healthy respect for high bvoltages as i am aware of the hazards involved.
Tony wrote:
"LOLZ! eat your heart out! these came from a box of 50, should i get them all? the shop owners says he has GE's but i have yet to see them."
The GE's are not that much in the sonics department, if my GE 6AQ5s are anything to go by. Not that they are bad, just that I replaced them with Philips, and my amp lit up like a sonic christmas tree! I was truly flaberghasted at the difference - just from changing the tubes! Still, as SY said,
"price for those tubes here in the US is north of $60 per tube."
so they'd be great for initial build and to get the cct trimmed - then swap them for sonically better ones. If it was me, I'd buy 'em all at that price!
Merry Christmas all
"LOLZ! eat your heart out! these came from a box of 50, should i get them all? the shop owners says he has GE's but i have yet to see them."
The GE's are not that much in the sonics department, if my GE 6AQ5s are anything to go by. Not that they are bad, just that I replaced them with Philips, and my amp lit up like a sonic christmas tree! I was truly flaberghasted at the difference - just from changing the tubes! Still, as SY said,
"price for those tubes here in the US is north of $60 per tube."
so they'd be great for initial build and to get the cct trimmed - then swap them for sonically better ones. If it was me, I'd buy 'em all at that price!
Merry Christmas all
Some GE tubes are excellent. My favorite sweep tube is the 6LW6. Of these there are at least 6 different constructions with several different brand names on each kind. There are two different kinds of GE's, and these are the best sounding, and most indestructible of them all. I would rate the RCA's way below the GE's in this tube type.
I have experimented with the 3DG4 (all of them were Zenith brand). They require a 3.3 volt, 4 amp filament supply which can be hard to find. I used a resistor on a 5 volt transformer. The tube looks like a super 5AR4, and the voltage drop and regulation is similar, if not better than a 5AR4. The problem comes when you try to run them at voltages above 400 volts output. They arc over, plate to cathode. This happened with a 750 volt CT transformer, and a 40uF input cap. Two different tubes sparked out, so it wasn't a bad tube. I did not try the arrangement that you propose though.
I have experimented with the 3DG4 (all of them were Zenith brand). They require a 3.3 volt, 4 amp filament supply which can be hard to find. I used a resistor on a 5 volt transformer. The tube looks like a super 5AR4, and the voltage drop and regulation is similar, if not better than a 5AR4. The problem comes when you try to run them at voltages above 400 volts output. They arc over, plate to cathode. This happened with a 750 volt CT transformer, and a 40uF input cap. Two different tubes sparked out, so it wasn't a bad tube. I did not try the arrangement that you propose though.
Hey-Hey!!!,
The data sheet o the 3DG4 shows it to be a directly heated valve like a 5R4 or 5U4. Is it really a DH?
Been eyeing these for use in a 2A3 amp. I'd run 325-0-325 into a choke for something on the high side of 250V, and run the 2A3's fixed bias. My wife wants to build an amp, and I figure this will be a nice way to keep things inexpensive while keeping the design free of weak parts.
If I go a bit more than 250V, it's OK since I have a 6k6 a-a output TX in store. It'll still be full-on Class A.
The whole thing is going to get special Iron wound, so the 3V supply for the rectifier is no biggie.
cheers,
Douglas
The data sheet o the 3DG4 shows it to be a directly heated valve like a 5R4 or 5U4. Is it really a DH?
Been eyeing these for use in a 2A3 amp. I'd run 325-0-325 into a choke for something on the high side of 250V, and run the 2A3's fixed bias. My wife wants to build an amp, and I figure this will be a nice way to keep things inexpensive while keeping the design free of weak parts.
If I go a bit more than 250V, it's OK since I have a 6k6 a-a output TX in store. It'll still be full-on Class A.
The whole thing is going to get special Iron wound, so the 3V supply for the rectifier is no biggie.
cheers,
Douglas
hi Bandersnatch ,
yes it is really a DH diode, with very short spacing between plate and filament that is why the low voltage drop of 25volts @350mA.
but the plate to plate input limits to 500v, the sections have a 1kv piv. so i figure if i get two of them, i will have a 1kv, 700mA rectifer.
heaters are rated 3.3A at 3amps.
they cost lest than U$10 also. in fact the store where i got them sells every tube for that price, an there are still lots of tv tubes in his stock.
yes it is really a DH diode, with very short spacing between plate and filament that is why the low voltage drop of 25volts @350mA.
but the plate to plate input limits to 500v, the sections have a 1kv piv. so i figure if i get two of them, i will have a 1kv, 700mA rectifer.
heaters are rated 3.3A at 3amps.
they cost lest than U$10 also. in fact the store where i got them sells every tube for that price, an there are still lots of tv tubes in his stock.
SY said:
Yes, it is a 6JE8 and it is small so i guess it is a small signal tube. They also gave me PCF80, PCF800, PCF801, PCF802, 12BH7A(*) and lots of other television tubes, apart from some tunning indicators that i plan to use to make a cool vu-meter. They gave me all the tubes they had (aprox 200) when i bought the scope. There are also 6JM6 and other big tubes.
But it's very hard to find a good-sounding amp using them (*): This is the exception, too bad they had only one.
The 6146B has been used in audio amplifiers. There are those who will say that it is poorly suited for audio use. This is traced back to a single amplifier design that suffered some very public failures. The original Ampeg SVT bass guitar amp used 6 X 6146B in PPP to produce 300 watts. The amp head usually sat on top of a cabinet that housed 8 ten inch speakers, so it took a lot of vibration. Ampeg ran the screen grids of the 6146's on the edge of red glow. A glowing grid is bad, a glowing grid and a whole lot of shaking going on is very bad!
There was a Rolling Stones concert that was on live TV where the SVT exploded in flames. I was present at an outdoor concert in Miami when an SVT caught fire it was an awesome sight. I later got to fix that amp. Autopsy revealed a dead OPT, a dead power transformer, some burnt resistors and some blown tubes. It also revealed that the amp was not at fault. The user had fed 300+ watts into a Traynor cabinet that was meant for 50. Both speakers went open leaving the amp with no load. The second generation SVT used 6550's and worked great, but still would have blown up under this situation.
The moral. The 6146 can be used for audio. The screen grid is rated for 250 volts (similar to most sweep tubes). Believe it, I am one to bend ratings, but not here. This pretty much rules out triode or UL operation except at low power levels. However P-P pentode mode with a regulated screen grid supply does work. 50 watts per pair of tubes is easy, Ampeg was making 100, but somewhat unreliably. I don't have a schematic handy, but just about any P-P schematic with a regulated screen grid supply can be modified to work. As with any amp design that does not use mainstream tubes, expect to do some experimenting.
There was a Rolling Stones concert that was on live TV where the SVT exploded in flames. I was present at an outdoor concert in Miami when an SVT caught fire it was an awesome sight. I later got to fix that amp. Autopsy revealed a dead OPT, a dead power transformer, some burnt resistors and some blown tubes. It also revealed that the amp was not at fault. The user had fed 300+ watts into a Traynor cabinet that was meant for 50. Both speakers went open leaving the amp with no load. The second generation SVT used 6550's and worked great, but still would have blown up under this situation.
The moral. The 6146 can be used for audio. The screen grid is rated for 250 volts (similar to most sweep tubes). Believe it, I am one to bend ratings, but not here. This pretty much rules out triode or UL operation except at low power levels. However P-P pentode mode with a regulated screen grid supply does work. 50 watts per pair of tubes is easy, Ampeg was making 100, but somewhat unreliably. I don't have a schematic handy, but just about any P-P schematic with a regulated screen grid supply can be modified to work. As with any amp design that does not use mainstream tubes, expect to do some experimenting.
I found this thread while searching for something else. Some links to 6146 schematics. The 6159 is the same as a 6146 except for the 28 volt filament (aircraft use).
http://www.diyaudio.com/forums/showthread.php?s=&threadid=70571&highlight=
http://www.diyaudio.com/forums/showthread.php?s=&threadid=70571&highlight=
Don't have any here in the house, maybe some in the warehouse. I will look this weekend. I brought home some boxes of tubes last weekend to go through and "test". I found a bunch of E130L which I assumed were sweep tubes when I stuffed them into a box. They are the surprise of the wek, they ROCK!
I just opened the last box tonight. It contained about 100 assorted loose crusty dirty tubes including (surprise) an 813. There were also several 6146's in the box. If any are good, I'll smoke test them over the long weekend. If I remember correctly they will not work well in a triode SE amp which is what I have to work with right now, but I'll try them anyway.
This box must have come from a two way radio shop. Many VHF looking tubes including some that are unknown to me. 7984 a VHF compactron, looks like a beam triode or tetrode, GE and Motorola brands. 8106, smaller 9 pin version of the same. GE brand. A bunch of really toasted 24 and 31 volt sweep tubes. I bet they worked on CB linears too.
tubelab.com said:
Damn, another of my secret output tubes discovered.
These 7534s were never used in TV's, but served well in a Hewlett Packard high power pulse generator. (2 in parallel SE) Both the control and screen grid are frame types and can provide transconductance of 25,000 µmhos. A very interesting tube!Victor
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