6P14P Amp Scratch Build

mitwrong · 2006-12-25 4:26 am

motherone said:
as I found an ebayer selling 6P14P (Sovtek EL84s?) and picked up 40 of them at $2/each. eBay is definitely the place to get them, as the web shops are selling them for $7+ each!

Guys:

I want to repeat : 6p14 is made in China, and 6pie14pie, is made in Russian, on my keyboard, it doesn't has a " pie " symbol.

At Ebay only $2/each, Don't you think that is OK?????

I have bought tubes from Ebay, very cheap! But only 10% can work. the rest all went to junk yard!!!! Imagine how can a working tube sell at $2 of EL84???? Only an AB resistor cost???
Those tubes are selected ones, worse ones!!!! Don't try to pick up a penny without sweat ed!!!!

Good Luck! and have fortune!

sorenj07 · 2006-12-25 5:33 am

I don't see what the debate is here...

anyway, merry christmas, all!

p.s. i tried a quad of my RUSSIAN 6p14p's and they were all very close to each other, and sound great. i had no problems changing my 20-ohm pots to match them to .1mA of each other. ymmv.

motherone · 2006-12-25 5:39 am

My understanding of translating the "Pi" symbol is that it's indicated as 6N14N or 6P14P. While 6P14 may be the Chinese designation, folks chose the 6P14P as many do not have a way of putting in cyrillic characters.

As far as the tubes go, the ones I picked up came in a box marked Sovtek EL84, and the tubes look absolutely pristine. I've no way to tell if they're bad, but the seller sold them at a loss (I had a lengthy discussion with him regarding them).

I'm not particularly worried about it. Even if half of them are okay, it's still a good deal.

Eventually I hope to pick up a tube tester and match them up.

Also, there are sellers from eastern europe offering them up pretty inexpensively on there, for un-branded EL84 (6P14P), usually at $2-4/tube, depending on the quantity.

rdf · 2006-12-25 6:16 am

Same here, bought 16 of the Russian EL84M equivs and haven't seen a dud yet. They all measure as close as any other brand. EH on the other hand have been junk in my experience, so no-name doesn't always indicate no quality.

jon_010101 · 2006-12-25 7:39 am

motherone said:
My understanding of translating the "Pi" symbol is that it's indicated as 6N14N or 6P14P. While 6P14 may be the Chinese designation, folks chose the 6P14P as many do not have a way of putting in cyrillic characters.

Cyrllic "H" -> "N"
Cyrllic "Pi" -> "P"

I suspect the only reason they indicate it on eBay as lower case "n" is because it is the closest shaped character to a Pi. Using P is a totally valid translation, just as we say 6N1P rather than 6H1Pi :smash:

Searching for 6P14P on eBay yields Russian tubes, 6P14 yields Chinese tubes.

motherone · 2006-12-25 11:39 am

The only experience I have so far with EH is their 12AU7 for a SOHA amplifier. It's by far the quietest I've tested so far. The Chinese 12AU7 is extraordinarily noisy. I've tried some vintage ones as well, but I have about 15 brands to try out and haven't gotten to all of them yet

Hopefully the ones I bought weren't duds. They seriously look flawless, so unless the guy I purchased from was shipped ones that weren't to spec (which I doubt), they should be fine!

All I have to say is that you've got to love eBay!

sorenj07 · 2006-12-25 4:28 pm

sorenj07 said:
Well, I'm drawing around 192mA of current through the 6V3-A's and they seem to be holding pretty steady, but it's still kind of disturbing. The amp has worked so far, I rarely listen very loudly. Is it worth replacing each 6V3-A with a paralleled 6CA4 (which I can definitely do) or should I not sweat it?

note: datasheets I've seen for the 6V3-A specify 600-800mA steady peak current and 135mA DC current...

anyway, back to topic... any ideas?

Zibi · 2006-12-25 6:02 pm

Off-topic but useful: russian tubes numbering system
http://www.jogis-roehrenbude.de/Russian/Russische_Roehren.htm

Menator · 2006-12-26 8:53 pm

The tube 6P14P(EV) is made in USSR. It's russian. Most of this tube are made in Svetlana factory in Leningrad. I have many. It is the russian version of EL84 tube. The military version are "EV". The other are only 6P14P.

Zibi · 2006-12-28 4:53 pm

sorenj07 said:
Well, I'm drawing around 192mA of current through the 6V3-A's and they seem to be holding pretty steady, but it's still kind of disturbing. The amp has worked so far, I rarely listen very loudly. Is it worth replacing each 6V3-A with a paralleled 6CA4 (which I can definitely do) or should I not sweat it?

note: datasheets I've seen for the 6V3-A specify 600-800mA steady peak current and 135mA DC current...

anyway, back to topic... any ideas?

Don't change anything.

kevinkr · 2006-12-28 5:05 pm

Yeah, I think you are fine with the 6V3. The average current each rectifier is providing is 50% of your total load current so you are well under the 135mA continuous rating.

sorenj07 · 2006-12-28 6:01 pm

That makes some sense. If I were in fact exceeding the ratings by that much, could I have expected to see some arcing or something?

Zibi · 2006-12-28 7:34 pm

In the case of overcurrent plate starts to glow.

mitwrong · 2007-01-02 9:28 am

Plate glow

Zibi said:
In the case of overcurrent plate starts to glow.

Hi, Gents:

Can anyone tell me why second grid glows instead of plate?

Usually both of them will glow together, but my amp. only second grid glows. In this case, will it shorten the tube life? How long can the tube runs in this condition? Thanks

kevinkr · 2007-01-02 2:12 pm

Depending on what you mean by glow it could be excessive screen current in which case you will see the screens glowing dull red. The fix is obviously to reduce screen current to acceptable values.

Alternately it is not at all unusual particularly with the current crop of modern, umm somewhat "gassy" tubes to see quite a lot of blue around the screen grid wires in pentodes. What you should not see is a blue haze inside the tube in general, but a very distinct blue field just around the wires themselves.

vlrk · 2007-01-02 3:42 pm

Menator said:
The tube 6P14P(EV) is made in USSR. It's russian. Most of this tube are made in Svetlana factory in Leningrad.

Most of this tube are made in Reflector factory in Saratov

mitwrong · 2007-01-03 1:55 am

kevinkr said:
Depending on what you mean by glow it could be excessive screen current in which case you will see the screens glowing dull red. The fix is obviously to reduce screen current to acceptable values.

Alternately it is not at all unusual particularly with the current crop of modern, umm somewhat "gassy" tubes to see quite a lot of blue around the screen grid wires in pentodes. What you should not see is a blue haze inside the tube in general, but a very distinct blue field just around the wires themselves.

Thanks for your info. My tube is second grid dull red. not blue, I have seen blue haze when the tube is new, but this time is 2grid got red, it follows the music to " dance ". I have lowered dn the 2grid voltage, then the problem cured. but the sound reproduction not as good as before! less " punch ".

sorenj07 · 2007-01-07 8:08 pm

Well, the time has come to say goodbye. I've got my eye for bigger and better things, but I also have an empty wallet . It was fun, and thanks a lot for the help with designing this thing.

http://boston.craigslist.org/gbs/ele/259007005.html

jrdmedford · 2007-01-08 12:04 am

nice work

Also from Boston. We've talked before at some point. So whats
next??? I can help you out with getting better results with the
metalwork. I'm a whiz at FPE designer.

Amity Clones

The amps in the photo use MQ-565s, the Triode Electonics ST-35 power tranny clone. The itself is an Amity clone. I'm using 12AV5's strapped
Triode (look like 2A3s), 6AX4 damper rectifiers and 12BH7 as drivers.

The top plates cost $170 to fab a pair (lots of countersunk holes). You can get the Walnut boxes for another $140.

For you next trick, you should do a Triode KT66 or KT88 PP amp.

-- Jim

sorenj07 · 2007-01-08 2:04 am

Thanks! Anyway I don't really mind hand-drilling the things, and I'll probably drop around $80 for a pair of Hammond chassis for the monoblocks I'll be building... Your amps look very nice though

I remember talking about some MJL chips, I still have them if you want..

My new project is a 6L6 amp, and its thread is in the Tubes section. I'll probably run it in UL because I want more power, and besides, I have some 6S19P power triodes coming that I can have fun with

6P14P Amp Scratch Build

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