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Old 25th March 2004, 03:08 PM   #1
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Default Plitron/Vanderveen/KT88 Tube rectifier recommendation for 230mA?

Howdy again...

Seeing I have read a bit of bull about valves being less noizy than diodes for rectification I am now considering a LCLC or LCRC setup and have looked at the humble & popular 5AR4, only problem is, it isn't anywhere near enough to survive the peak caused by having a choke first. The tube is rated for 250mA, that's riding on borderline 230mA estimated load for 1 channel. (120 / 525 = 0.228)

Sure I could double up, but that's 4 tubes for one bridge side! Octal! Maybe not such a bad idea.

http://www.plitron.com/pages/Products/Audio/vtvkt88.htm
So as my last attempt of using this design with tubes I am asking if you guy's know of any tubes which would be suitable and replacable ? Probably asking the earth

Preferrably something that can handle 8-50uF for frontline cap in a CLC or CLCRC run as I need the higher reservior voltages to drive this amp properly at 490-525v or thereabouts..

Also with supply restrictions it is preferred that I could get them off some webpage, don't matter if it's dusty and the pens don't work, I'll write them a cheque on stone

Having to ring them up and speak in tounges isn't however on my agenda that's just toooo weird

I've run PSUD in a LCRC and LCLC manner only to find a 350 or odd volts out of both diode and 5AR4x2 (parallel or single).

Theres no way this design would run below 470v and still be the same amp. If there is I'm not interested.

It seems the evil 866-A is the only thing in PSUD which gives me a soft voltage drop at the expense of my life and endanger to wild animals of running the tube at borderline explosive instability

That and standing the cat's hair on end everytime it crosses the doorway

Having two chokes for one side may be a problem, however I'm willing to live with it, just makes things in the ps region a bit cramped. But still well ventilated.

Cheers.

Legend:
LCLC = Choke|Cap|Choke|Cap
LCRC = Choke|Cap|Resistor|Cap
CLC = Cap|Choke|Cap
CLCRC= Cap|Choke|Cap|Resistor|Cap
LCRC = Choke|Cap|Resistor|Choke
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Old 25th March 2004, 05:13 PM   #2
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Your post is a little confusing....you're searching for a more massive tube rectifier?!?
If yes,check this out:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3805144763
This Russian beast has a PIV of 1700 V and a nominal current cappability of 400 mA (but you can pull a max.of 1,4A from it!).It is the most powerful double rectifier known by now in terms of current.
HTH!
Enjoy,
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Old 25th March 2004, 06:09 PM   #3
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Fast recovery silicon diodes really would be your best choice.

(...as he shamefacedly returns his Valve Lovers ID card, badge, and decoder ring)
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Old 25th March 2004, 07:30 PM   #4
316a is offline 316a  England
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Default Re: Plitron/Vanderveen/KT88 Tube rectifier recommendation for 230mA?

Quote:
Originally posted by Layberinthius

Preferrably something that can handle 8-50uF for frontline cap in a CLC or CLCRC run as I need the higher reservior voltages to drive this amp properly at 490-525v or thereabouts..

Also with supply restrictions it is preferred that I could get them off some webpage, don't matter if it's dusty and the pens don't work, I'll write them a cheque on stone

Having to ring them up and speak in tounges isn't however on my agenda that's just toooo weird

I've run PSUD in a LCRC and LCLC manner only to find a 350 or odd volts out of both diode and 5AR4x2 (parallel or single).

Theres no way this design would run below 470v and still be the same amp. If there is I'm not interested.

It seems the evil 866-A is the only thing in PSUD which gives me a soft voltage drop at the expense of my life and endanger to wild animals of running the tube at borderline explosive instability

That and standing the cat's hair on end everytime it crosses the doorway

Having two chokes for one side may be a problem, however I'm willing to live with it, just makes things in the ps region a bit cramped. But still well ventilated.

Cheers.

Legend:
LCLC = Choke|Cap|Choke|Cap
LCRC = Choke|Cap|Resistor|Cap
CLC = Cap|Choke|Cap
CLCRC= Cap|Choke|Cap|Resistor|Cap
LCRC = Choke|Cap|Resistor|Choke
Hello ,
866A may look nice but you could try some simulations with 6D22S for an alternative . This is a damper diode similar to the PY500/EY500 or 6EC4/42EC4 . I'm using a pair of PY500a to deliver 390V at 380mA in my new project , the sims I use are for the 6D22S and the test results are very similar . PY500 are inexpensive , readily available and if you can put up with the topcaps , excellent in use . Slow start , low voltage drop , high peak current capability and quiet switching are all characteristics of these valves . PY500 are series string valves , designed to run at 300mA . I noticed that at power on the filaments flashed so I use a dropper resistor and a higher voltage filament supply , this also adds about 5 seconds to the warmup time (filament resistance at cold is low) . As used in the last generation of colour TV sets . There are now literally tens of thousands of these valves out in the marketplace , well worth having a few in stock for projects



316a
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Old 25th March 2004, 10:43 PM   #5
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>>looked at the humble & popular 5AR4, only problem is, it isn't anywhere near enough to survive the peak caused by having a choke first. The tube is rated for 250mA, that's riding on borderline 230mA estimated load for 1 channel. (120 / 525 = 0.228)<<<

Hi there.........some 40 years ago I repaired a Trix amp which used 4x 5U4's in parallel.....impressive heat radiation......there's nothing wrong with this tact so long the heater supply has the stick........bear in mind the instant peak voltage from a direct heated rect......this was the norm with lo value paper/oil caps in those days.

With electrolytics as smoothers.... seek an indirectly heated rect type. The GU34 is overpriced for what it is........there are other possibilities.

You seem undecided whether you are after an capacitive input type filter or inductive one......i.e amp using cathode bias or fixed bias ??

rich
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Old 26th March 2004, 01:14 AM   #6
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Quote:
SY Fast recovery silicon diodes really would be your best choice. (...as he shamefacedly returns his Valve Lovers ID card, badge, and decoder ring)
I'm willing to challenge this motion tho

Quote:
Hello , 866A may look nice but you could try some simulations with 6D22S for an alternative . This is a damper diode similar to the PY500/EY500 or 6EC4/42EC4 . I'm using a pair of PY500a to deliver 390V at 380mA in my new project , the sims I use are for the 6D22S and the test results are very similar . PY500 are inexpensive , readily available and if you can put up with the topcaps , excellent in use . Slow start , low voltage drop , high peak current capability and quiet switching are all characteristics of these valves . PY500 are series string valves , designed to run at 300mA . I noticed that at power on the filaments flashed so I use a dropper resistor and a higher voltage filament supply , this also adds about 5 seconds to the warmup time (filament resistance at cold is low) . As used in the last generation of colour TV sets . There are now literally tens of thousands of these valves out in the marketplace , well worth having a few in stock for projects
Thanks! I'll look into them!


Quote:
Your post is a little confusing....you're searching for a more massive tube rectifier?!? If yes,check this out: http://cgi.ebay.com/ws/eBayISAPI.dl...item=3805144763 This Russian beast has a PIV of 1700 V and a nominal current cappability of 400 mA (but you can pull a max.of 1,4A from it!).It is the most powerful double rectifier known by now in terms of current. HTH! Enjoy,
It may be just the ticket !

/me watches as his bad sugar addiction turns translators crazy everywhere

Ookay, "According to PSUD" :P we get 470v at 230mA with the PY500A's in Bridge, With diodes it's 500v. a 30v drop, not exactly heart-breaking!

With the Svetlana 5C8S's I'm /assuming/ from the voltage curve
that there will be a 100volt drop. taking it to 400v.

For now it looks like we have a winner, although a bit of a pain with the length.

Still open for suggestions!
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Old 26th March 2004, 01:46 AM   #7
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Ookay, "According to PSUD" :P we get 470v at 230mA with the PY500A's in Bridge, a 30v drop, With SS diodes it's 500v. not exactly heart-breaking!
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Old 26th March 2004, 01:47 AM   #8
EC8010 is offline EC8010  United Kingdom
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How about U19? It's good for high voltages and 500mA load current. Data sheet on Frank's site:

http://frank.pocnet.net/sheetsU.html

Might need to go choke input, though.
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Old 26th March 2004, 01:54 AM   #9
SY is offline SY  United States
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Quote:
I'm willing to challenge this motion tho
High efficiency, low heat, high reliability, low noise, low drop, low source Z. Challenge away!
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Old 26th March 2004, 02:02 AM   #10
EC8010 is offline EC8010  United Kingdom
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Quote:
palpably untrue... (couldn't resist it)
I tried some 600V Crees. They were inside ratings (just). The result wasn't merely a bonfire, it was a volcano, with a most impressive purple-white heart. Took a lot of cleaning up.

The more conventional silicon diodes are rather more sensible...
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