6P14P Amp Scratch Build - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th November 2006, 01:39 AM   #11
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
Update: Got a pair of Z565 OPT's from Doug over at AK, and laid out my potential config. Tubes seem really close to each other, which is making me think that I might have to go with a clunky-looking 16x8x3" Hammond aluminum box...

Click the image to open in full size.

Click the image to open in full size.

Yes, those 6V3-A's are unequal heights, and one is slanty, but those deadbeats at Triode aren't shipping me the other two that I ordered. They're a buck each, but it's the principle of the thing
  Reply With Quote
Old 30th November 2006, 06:34 PM   #12
Zibi is offline Zibi  Poland
diyAudio Member
 
Join Date: Jan 2006
Location: Bialystok
Default Re: 6p14

Quote:
Originally posted by mitwrong
Solenj07:

First, I want to make a correction on your brain. The tube 6P14 is not from Russian, It's from China. The tube marked with letter J is designed for military use.

It is true. Russian (rather Soviet Union) tubes during copying in China lose one letter in numbering system :-)
6p14p - 6p14
6n1p - 6n1
  Reply With Quote
Old 30th November 2006, 07:10 PM   #13
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Thanks to this thread I bought some 6P14P-ER on eBay to try in my old Realistic Stereodyne 40 which isn't too kind to current production 6BQ5. It ran the originals quite a bit hotter than recommended and the replacement JJ's barely handle it even at significantly reduced Vp.

The original design voltage was about 390V and with modern line voltages it is now slightly over 400V. In addition I'll use a small value power resistor (22 - 100 ohms) from the power transformer ct to ground to drop some volts as needed.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 8th December 2006, 02:35 AM   #14
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
Major update. After using the 16x8x3 Hammond after all, I'm using .047uF orange drops on the positive side, and .1uF orange drops on the negative. I guessed that the yellow wire on the Z565's was the 8-ohm tap, and not the orange one, because it had slightly higher resistance. I also soldered a free-hanging 10K 1/4W resistor to put some moderate feedback to the bottom of the cathode.

Biasing. I'm still seeing around 300V B+ to the CT, and will probably use a resistor network of 130 ohms + 10 ohms + 0-20 ohm pot on each, bypassed with a 470uF cap. My design center was 150 ohms per tube for 40mA, -6V. It'll be easy to change to a CCS though, because the whole bias network for each tube will be on individual stand-off perfboards near each 6P14P

I have drilled most of the holes, not those for the bias boards, and wired up the heaters, and it looks pretty sweet. One of the 6V3-A's lights up A LOT more than the other, also it is much shorter (I need to get more of those things). I'll post pics as soon as I bite the bullet and buy a $40 charger for those pesky proprietary batteries.
  Reply With Quote
Old 9th December 2006, 03:56 AM   #15
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
Update: put the thing together, the actual measured bias is a bit weird, but i matched the tubes to .1mA of each other so it should be good. Bass is absolutely pounding, without being muddy. the high end is a bit darker than before but still seems plenty clear.

Measurements:
B+: 274V
B++: 260V

Tubes 1-2 (left): 48.0mA each
Tubes 3-4 (right) 48.3mA each

I'm not using any feedback, I have a 10K resistor hanging off the hot binding post in case I want to try. What improvements could I expect?

I also notice that my linestage has a lot of hum, probably because the transformers aren't isolated from the chassis with grommets, and the PT and choke are close to each other, with cores parallel .

but yea i'm pretty pumped that it works, pics soon (ttiwwop)
  Reply With Quote
Old 9th December 2006, 08:41 PM   #16
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
final schematic

Click the image to open in full size.

the capacitor input is a nice solen. the signal coupling caps are two orange drops, and .56uF solen's.
  Reply With Quote
Old 9th December 2006, 10:02 PM   #17
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
Well, I had the 16-ohm tap connected to the output jack, and now that I connected the 8-ohm tap, bass is less dominant and treble has reappeared, so everything feels in balance. Great to listen to . Hum/noise with inputs shorted are absolutely nil.

Here are some pics, at long last.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
  Reply With Quote
Old 10th December 2006, 09:52 AM   #18
diyAudio Member
 
Join Date: Apr 2003
Location: Seattle
Very nice build! I may have to try your schematic out, 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!

Now I'm itching to see what can be built with these guys, and your design looks like it uses a lot of parts that I have sitting around. I really just need the PSU iron and the output iron. Maybe using the dynaclone transformers from Triode Electronics?

http://www.triodeelectronics.com/z517wadyoutr.html

If you don't mind me asking, where did you source the toroid from?

Finally (and most importantly), how does it sound?
  Reply With Quote
Old 10th December 2006, 04:20 PM   #19
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
Thanks! I really love how it sounds, and I really didn't feel the need for feedback. You can use a regular 6DJ8 instead of the 6N23P. I basically had the 193K and the PT left over from projects that I kept on changing, so I wanted to throw an amp together cheaply. I got the 6N23P's free, and got the cheap 6P14P's, but was persuaded to not cheap out on the iron. I highly recommend this project to anyone But maybe use a 2" box instead, the 3" is kind of clunky

As for the iron, I used the Z565's so I recommend those. I'm not sure if the 1650E has UL taps, but if it does, that's definitely a fine transformer to use. Finally, I'm a big fan of Edcor (though I haven't used the transformers I bought from them yet) so definitely give them a look, here. Their 7600 ohm OPT's should probably work, but you can always ask them to make you some 8000-ohm ones.

http://www.edcorusa.com/classx/tube_.../cxpp/cxpp.htm


I'm not sure if the power transformer is any better or worse than Hammond, but its secondary resistance is something like 56 ohms across a 275-0-275V secondary, with current of up to .5A. I like using parts conservatively so it appealed to me. Here's their eBay store. They have recently added many more power transformers to their lineup.

http://stores.ebay.com/Antek-inc

Thanks for your interest!
  Reply With Quote
Old 24th December 2006, 11:00 PM   #20
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
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...
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
scratch build EAR834p fallendragon Tubes / Valves 0 5th April 2008 03:47 PM
My 1st scratch build complete...... JandG Tubes / Valves 6 23rd April 2007 01:25 AM
My 6P14P Amp sorenj07 Swap Meet 1 10th January 2007 12:06 AM
First build from scratch. castlesteve Tubes / Valves 0 29th January 2004 04:33 PM


New To Site? Need Help?

All times are GMT. The time now is 03:21 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2