| SY |
| Gain is pretty low for that, to judge from the sketchy specs. I'd sure love to have 4 of these to build a real plus-size amp. |
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| ShiFtY |
That would make a fine amp- but really it would only be any good in push pull. Imagine a SE output tranny for that! It would have to be MASSIVE.
I think you should get another one and make a subwoofer amp.
Either that or get a 12V 10A transformer and make yourself a nice bedside lamp/heater. That thoriated filament should be pretty darn bright! |
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| Brett |
| quote: | Originally posted by ShiFtY
That would make a fine amp- but really it would only be any good in push pull. Imagine a SE output tranny for that! It would have to be MASSIVE. |
I was just thinking SRPP with the OPT in shunt. That way you could save some money and use an old PP trans or a Hammond :)
| quote: | | Either that or get a 12V 10A transformer and make yourself a nice bedside lamp/heater. That thoriated filament should be pretty darn bright! |
Sure will!. I use an old 803 as the 'nitelight' next to my TT so I can change discs without turning on the main room light. |
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| beamnet |
Cool thread!
I want to use the tube too. Could you elaborate on that srpp thing?
I have everything to make a ps and make an amp, but i am still hung up on that opt thingy ;)
Strapping it in triode would make the output wattage a lot lower wouldn't it?
Could anybody give me a real feasible proposition?
bas |
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| Tweeker |
Datasheet here.
ry=gu. rY. Cyrillic letter that looks kind of like a large r translates to G.
I think your going to need to use it PP or in parafeed etc arrangement for OPT. An SE OPT could be made, but will probably not cover full audio spectrum. See this thead for more high power SE discussion. 450watt anode dissipation, its slightly bigger than an 833A.
It could also be used to make a wicked plasma mid/tweeter, if you like the taste of ozone.
Output power is cited with 300V drive, I dont think this is spud material. |
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| jlsem |
| quote: | | I'd sure love to have 4 of these to build a real plus-size amp. |
I bought four from this guy recently. Excellent service and very fast shipment. I also had a used one for a mule. Can anyone point me to a good 400W ultralinear P-P OPT of 3-4K primary impedence?
http://cgi.ebay.com/GU-81M-Large-Gl...1QQcmdZViewItem |
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| Tweeker |
Hammond 1650w
280 watts RMS
1,900 ohms ct
806 ma. max current per winding
4-8-16 ohms secondary
28 pounds
Has 40% UL taps. |
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| Giaime |
My God, they're.... BIG!
800W plate dissipation... that's calling for triode strapping A2 PP!!!! And what can drive them? A triode strapped KT88 with an interstage tranny maybe?
I would really love to see pictures of an amp made with these. These will really put shame on TubeLab's 833 ;) |
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| Giaime |
| quote: | Originally posted by Tweeker
Hammond 1650w
280 watts RMS
1,900 ohms ct
806 ma. max current per winding
4-8-16 ohms secondary
28 pounds
Has 40% UL taps. |
2 of them in series maybe? :xeye: |
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| beamnet |
output's in series, the input's parallel!
I am still temted.I can buy these wehrmacht Rl12 p35 tubes (also with top cap's)
I am very well stocked with cv6 variants (with two top caps) to drve the Rl tube...
havent crunched any numbers, but they would look tha bomb! |
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| Tweeker |
800 watts is "output", not plate dissipation. Plate dissipation is rated at 450 watts continous, 600 watts momentary (peak).
You might be able to use the Hammond by using using the "wrong" secondary tap. *
*Not liable for magic smoke releases. |
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| tubelab.com |
| quote: | | These will really put shame on TubeLab's 833 |
This sounds like a challenge!
| quote: | | Strapping it in triode would make the output wattage a lot lower wouldn't it? |
| quote: | | that's calling for triode strapping A2 PP!!!! |
The max G2 voltage is only 600 volts. Plate voltage could go to 3000 volts. Triode strapping would severely limit the output potential because of the 600 volt max rating. This thing wants to be run as a pentode.
It is a BIG good looking tube. It would make for a truly monstrous P-P amp, or It could be run in SE mode. Here the output transformer is the problem. SE transformers that handle above 75 watts are hard to make. I don't have the answer, but I am building a guitar amplifier using a transformer that I had custom made for the 833A. The transformer is not quite good enough for HiFi, and I only have one of them. When I find a transformer for HiFi, I will build a stereo 833A SE. I am considering the Hammond 1642SE, 75 watts SE.
I had some 4-1000 tubes that I was saving for "the big one" but I sold them because I realized that transformers would never be found for them. |
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| Tweeker |
| I wonder about the Plitron toroid intended for 2 GM70s (~=Svetlana SV572) parallel SE. DC current limit 400ma. Too bad they are $611 each for 1-4. :bawling: |
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| tubelab.com |
| $611 each, I am having trouble justifying $239 each for the Hammonds. |
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| mbates14 |
| Wernt those things designed for lower end RF power amplifiers, such as for 10meter, shortwave, and CB? |
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| Tweeker |
The Hammonds are a much better deal, especially if you, like me, have a tendancy to buy your electrical equipment by weight.
10meter is about the limit for this tube. |
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| tubelab.com |
| Many of the tubes that are now used for large SE amplifiers were originally designed for RF amplifier service. The 833A, 845, 211, 811A, 807, 813, and many others were all used in transmitting equipment years ago. Some people refer to these as transmitting tube amplifiers. |
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| rabstg |
| Why not just use a klystron? |
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| tubelab.com |
| Let's see, if I needed a lot of power at, say 1GHz, maybe I would. I had some military klystrons in my warehouse full of tubes. Couldn't find a use for them, so I sold them. Got boxes full of thyratrons, high voltage rectifiers, magnetrons, T/R tubes and about 1000 6AL5's. I don't think you could build a big amp with any of these either. |
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| BHD |
| quote: | | $611 each, I am having trouble justifying $239 each for the Hammonds. |
FYI, Angela Instruments has the big 75W SE transformers on sale.
I have no affiliation, blah, blah, blah...
:) |
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| Makofoed-6sn7 |
tubelab.com:
If you use 500 6al5 for each channel, I'm sure you get some power out of it and some pretty hot stuff. Just think of a amp with 1000 tubes... But I think it's a little work to wire up all the sockets. The filament current would be 300amps..
Anyone have 1000 6al5 and socket's to give away?
Best regards,
Magnus Kofoed |
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| Makofoed-6sn7 |
Look's like have been a little to fast there, 6al5 is a double small signal diode, equ eaa91, I am a european, not used to this fancy american system. I was thinking on 6aq5(el90). If i don't remeber wrong that is a 7pin version of 6v6.
But a funny idea at least?
Best regards,
Magnus Kofoed |
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| tubelab.com |
Yes the 6AL5 is an ugly little diode with very few uses. The 6AQ5 (EL90) is the "baby 6V6". Fortunately I have a large box full of these, and I have been using them in several amp experiments. They make great SE guitar amps in the 4 watt range, and they also sound good in triode mode SE for HiFi uses. I know that I have never been very practical but several hundred tubes in parallel would be a nightmare to maintain. i don't plan to connect more than 2 or 3 in parallel, because I also have some large tubes to play with (833A). So.... back to the original topic:
BHD remarked that Angela has the big Hammonds on sale. I checked their web site yesterday, and they are currently on sale for $222 USD each, so I grabbed the phone and called. The recording said that they " were closed, call back between 10 AM and 4 PM". That is about 20 minutes from now, I will order a pair of these and build the "big one". I have all of the other needed parts. |
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| Giaime |
| quote: | Originally posted by tubelab.com
I will order a pair of these and build the "big one". I have all of the other needed parts. |
Finally, TubeLab has decided ;)
Let's wait for some amazing red-glowing-in-the-dark pictures :D
Post your results please! Have you solved the problem of the 833 sockets? How do you plan to mount them in your amp? |
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| tubelab.com |
I have been calling Angela for 2 days without an answer, so I won't start on this until I actually have the transformers.
I plan to make my own sockets, but I haven't figured out exactly how yet. I may mount the tubes upside down to keep the deadly voltages below the chassis. I will test this idea for adverse heat build up before commiting to it though. |
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| Tweeker |
| Stop drooling. :yummy: |
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| Giaime |
| Ehehehe.... do I see even 2 845 in the lower left corner? ;) |
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| Tweeker |
I do believe those are 845s, drivers. :D
Tubelab, do you have any large hydrogen thryatrons, triggered spark gaps or other high power switchgear spare? I am fitfully working on a Marx Generator project, capacitors charged in parallel then discharged in series through spark gaps, but I havent a trigger yet. 1.34uF oil caps I will use pictured. Please and thankyou. |
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| tubelab.com |
I don't know what a Marx generator is, but with caps like those it has got to be cool.
I remember finding some pretty big tubes in the warehouse and discovering that they were hydrogen thyratrons. I put them back in a box. I just don't know exactly which box. I will probably go over there this weekend. I will look for them. I don't know what your definition of "large" is. I think the bigger ones were about 813 size, but I am not really sure.
I have a friend in the surplus business who had a big tube with welding cables comming out of the base. It was about 2 feet tall, glass. I don't know if he still has it. I will call him and check. |
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| jackinnj |
| quote: | Originally posted by Tweeker
r=g. |
like Hercule Poirot, you have figured out that p = r
(name the Agatha Christie novelette in which that was a clue and you win 10 NE5532's). |
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| tubelab.com |
| NE5532. Does that fit an octal socket? |
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| Giaime |
| This thread is very very scary people. :scared: |
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| robertr0816 |
With does caps youll make thunder and lightning too.
Stay safe and everybody 2000feet around you |
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| tubelab.com |
I found that web site a couple of years ago when I sent some pictures of my plasma ball experiments in a microwave oven to friends at work. Some one sent me the link. I built a 6 foot tall Tesla coil back in high school (1969) but found out that it would only make sparks indoors in an air conditioned environment. Here in south Florida the humidity is above 80% for most of the year.
What value are your caps, and how many are you going to use? How many volts is your HV supply? I may have some rectifier tubes that could work on a neon sign transformer. I gave up on the HV experiments years ago due to the humidity. I have no use for the HV parts that won't work in a big tube amp, and would like them to find a good home, but I am not sure what is left. I gave a lot of the HV stuff away already.
After the recent hurricane there were power pole transformers literally laying in the street. One of my crazy friends hooked one up to his generator in reverse using a large halogen light for a ballast. It made some seriously wicked sparks.
Don't fry yourself, or your friends and familly, or your neighbors cat! |
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| imix500 |
| Hey Tweeker, I've got a GE CG-5948 that has a good filiment and reservoir that might be of use to you. I have not been able to fully test it other than vacuum intact-ness. |
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| Tweeker |
They are 1.34uF 85kV working, 150kV surge GE Dielectrol II energy storage capacitors. Surplus from Los Alamos National Labratory. 4.8kJ each. I have 8. I have a 300ma 125kvp full wave CT xray transformer and a couple series Powerstat 1156Ds for charging. Im looking for another 1156D if I can find one cheap. 0-140V 50amp, 120V in. These sort of setups are indeed used for theatrical lightning, the caps are discharged through fine magnet wire of the desired lightning bolt shape.
Vacuum rectifyers are neat, Im not sure how the durability compares, but Id be worried about xray production at really high voltages. Id been toying with the idea of EIMAC 2-240As in an amp just because they are so damn purty. I have 7 8008s and could use #8, but buying all these toys and then going back to school to tuition thats more than doubled in the past 5 years has been hard on the wallet.
I need to work out remote charging circuit disconnect to protect the charger from kickback. Kickback destroying the voltage doubler of 5408s and caps on my friends neon transformer charger in a quarter shrinker was a huge development problem. The quarter shinker uses 3 15uF 30kV caps typically charged to 22kV or so. For obvious reasons Id also like remote triggering and scram bleeding of remaining charge.
Interior shot of quarter shrinker, theres a couple more pics in dirtiest lab thread in everything else. |
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| Tweeker |
Gah, I mispelled laboratory. :o
Ive played with some big Jakob's ladders, but messing with a downed pole pig is nutty:att'n: |
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| tubelab.com |
http://www.diyaudio.com/forums/show...8836#post808836
Yes, I have been reading this from time to time, and I don't know whether it would work or not. I have done some experiments using a "chokeless parafeed" circuit whic uses a SS or pentode CCS to feed a triode. This works well, but some of the intricate details in the music is missing. I have also tried using a CCS IC to load the other half of a P-P transformer. The results were similar. I think that the DC current flowing through a well designed SE transformer keeps the transformer in the linear part of its magnetic curve. It also minimizes the hysteresis effects.
I will get back to these experiments sooner or later. I would like to experiment with a toroidal OPT since the magnetic circuit is smaller, and these effects should be lower. For my 833A amp, I will use a conventional SE OPT since this will operate at 1500 to 2000 volts. I don't have any pentodes capable of this voltage, and mosfets will emit too much smoke.
| quote: | | Ive played with some big Jakob's ladders, but messing with a downed pole pig is nutty |
And making artificial lightning isn't? I am all for crazy experiments, but I was about 500 feet away when my friend performed the pole transformer experiments. It made a big plasma ball, and a wicked sound, but I expected a big bang, it didn't happen. When he tried connecting the transformer directly to the generator, the breaker blew. I suggested using a 1KW halogen lamp as a ballast, but it limited the current to much. We needed a bigger light bulb. |
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| Tweeker |
Of course it is. Id be concerned about damage and shock in the case of the downed pig is all, though I dont have the specifics of this case. From what I understand, most people killed by hurricanes are killed in the aftermath.
Ive let some smoke out of stuff trying to ballast big transformers, it is a bugaboo for many high voltage experimenters. Putting a welder with shorted secondaries in series is one popular approach, another method is using water heater or oven elements as resistive ballast. |
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| tubelab.com |
Yes, most hurricane deaths (at least in Florida) happen in the aftermath of the hurricane, often due to carlessness or just plain stupidity. Two people that I knew were killed in the days following hurricane Wilma (both were accidents).
In this case a pole pig was lying in the street, completely torn loose from the pole and associated wiring. I didn't think of either of your ballast ideas, or I might have tried them. That was probably a good thing. |
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| tubelab.com |
| quote: | | FYI, Angela Instruments has the big 75W SE transformers on sale. |
Actually, they don't. I called them every day last week, they were closed. When I got someone on the phone today I was told that they had none of these transformers in stock, and they were no longer going to carry them.
Back to the drawing board. |
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| tta60 |
| So, has anybody made an amp using GU 81 yet, please? |
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| DigitalJunkie |
| quote: | | I know that I have never been very practical but several hundred tubes in parallel would be a nightmare to maintain. |
This reminds me of a guy that used to hang out on rec.audio.tubes years ago- Nick Sheldon.
He's made some insane amps,stuff with like 1000 6AU6 tubes in parallel,running at 800V,and cranking out 500W of audio..
Anybody know what ever happened to Nick?
I wonder if he hangs out here? :confused: |
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| Wavebourn |
| quote: | Originally posted by tta60
What a light! |
120 W bulb. :D |
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| tta60 |
Anybody happens to know details about the amp from the picture attached and its godfather? I forgot where I'd got the pic from.
Thanks! |
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| Bandersnatch |
hey-Hey!!!,
I have a six-pack of these and four sockets...:) PP requires a substantial PS. Consider SE. Put that cathode current to use. In parallel it is ~23A. Run it through a dedicated coil on the OPT to cancell some of the DC in the plate circuit. I saw this done with the TL304 and it worked well.
SE Pentode would be able to run well over what an OPT could deliver, so why not draw a load line only a pentode would like: steep and through a 1k5V/250 mA operating point. 2k load perhaps?
cheers,
Douglas |
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| Cycline3 |
| OK, this thread is cool! |
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| tta60 |
| quote: | Originally posted by Bandersnatch
hey-Hey!!!,
I have a six-pack of these and four sockets...:) PP requires a substantial PS. Consider SE. Put that cathode current to use. In parallel it is ~23A. Run it through a dedicated coil on the OPT to cancell some of the DC in the plate circuit. I saw this done with the TL304 and it worked well.
SE Pentode would be able to run well over what an OPT could deliver, so why not draw a load line only a pentode would like: steep and through a 1k5V/250mA operating point. 2k load perhaps?
cheers,
Douglas |
Hi, Douglas,
Can you show some proper circuit?
TTA |
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