Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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

Heptode oscillators
Heptode oscillators
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 14th July 2009, 12:49 AM   #1
LoFi Ninja is offline LoFi Ninja  Jamaica
diyAudio Member
 
Join Date: Jul 2009
Arrow Heptode oscillators

Hi..

I'm wondering if it is possible to make a varible oscillator with ECH81 for audio use ? Like a little noise toy..

Also I found these tubes in an old, battered radio, do you got an idea what I should do with them ? Anything really..

EM80
EZ80
EABC80
'ECH81 X2
EL84
ECC85
EBF89
  Reply With Quote
Old 14th July 2009, 01:47 AM   #2
Wavebourn is offline Wavebourn  United States
Designer & Technologist
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Heptode oscillators
If you got also both transformers you can make a nice mono amp using EL84. EZ80 you may use as a rectifier, EM80 like a magic eye indicator. If there is a B+ filtering choke in that radio you can get a very nice small mono amp.
Was it Telefunken?
Does it have a vibrator to make AC from DC?

__________________
Nothing in the universe is perfect. The ideal things are the ones that are most optimal. Optimization criteria, what matters. When I hear "No Compromise Design", I want to take a sledgehammer and test how impact-proof it is.
  Reply With Quote
Old 14th July 2009, 02:51 PM   #3
LoFi Ninja is offline LoFi Ninja  Jamaica
diyAudio Member
 
Join Date: Jul 2009
Damn.. I only took the tubes.

I was on foot far away from home, and then suddenly the radio was just chucked in the road side.. I didn't check the brand or anything.
I guess I could try and see if it's still there.

The EZ80 is a Telefunken tube and the rest is Phillips Miniwatt.

Do you have a schematic somewhere for the amp ? I found a Mullard SE amp using an EZ80, EL84 and an EF86. I don't have spare money to spend on tubes so that one is a no go. Only ones that uses the tubes I found.
  Reply With Quote
Old 14th July 2009, 05:19 PM   #4
m6tt is offline m6tt  United States
diyAudio Member
 
Join Date: Aug 2007
ECC85, EL84 and EZ80 would indeed make a nice little mono amp. The ecc85 looks like a lower-mu 12AT7, so somewhere between AT7 and AU7. Probably makes an excellent driver for the EL84, and hopefully a nice voltage gain stage. It's not the *most* linear triode, but it's linear enough to look like it'll work from the curves. Sometimes those heterodyne mixers (ECH tube) are quite linear as voltage stages with the extra grids tied to plate, so that's another option. I'd use an isolation transformer to rectify the 230v mains into the ez80 for the B+/HT supply, and a seperate 6.3v filament transformer for the tube's filaments. The output transformer will need to be approximately 5-8k depending on bias points and desired power out, gapped for SE.

If you can find one more EL84, you can approximately double the power out and buy a cheaper output transformer by switching to push-pull. In that case, the ecc85 would be voltage gain + cathodyne phase splitter into the two el84 grids, both el84 cathodes connected to shared approx. 130 ohm cathode bias resistor. If that doesn't have enough gain, triode the ECH and put it in front of the ECC85.

Anyhow, that's what I'd do if I was dead set on making an amp from those tubes. Good luck!
  Reply With Quote
Old 14th July 2009, 05:25 PM   #5
m6tt is offline m6tt  United States
diyAudio Member
 
Join Date: Aug 2007
The EABC80 seems to have a nice linear triode in it as well, the duodiode-pentode tube would make a good CCS, at least...you have a few options for preamps!
  Reply With Quote
Old 14th July 2009, 07:13 PM   #6
LoFi Ninja is offline LoFi Ninja  Jamaica
diyAudio Member
 
Join Date: Jul 2009
Oh damn, most of what your saying I'm not getting.. I know basic electronics, but nothing about tubes..
  Reply With Quote
Old 14th July 2009, 09:06 PM   #7
m6tt is offline m6tt  United States
diyAudio Member
 
Join Date: Aug 2007
Please look at the stickied threads about high voltage safety & information sources in this forum, they're quite good!

Here's some links that may help with theory etc.:
http://www.freewebs.com/valvewizard/
http://www.tubecad.com/articles_2003...ier/index.html
http://www.angelfire.com/electronic/funwithtubes/
http://www.tpub.com/neets/

Here's some links for datasheets etc. for the tubes:
http://www.tubedata.org/
http://www.nj7p.org/Tube.php
http://tdsl.duncanamps.com/

Don't be afraid to experiment with cheap or free tubes! Next time grab the transformers too though Check second-hand stores for old tube radio consoles, music amps/equipt., or something like that to experiment with, esp. if you learn better with your hands and eyes than by reading. Good luck, it'll make more sense after some reading and soldering!
  Reply With Quote

Reply


Heptode oscillatorsHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Heptode audio preamp? ECH83 engels Tubes / Valves 23 28th November 2012 09:42 PM
1A7 Heptode (Pentagrid Converter) Audio Preamplifier esoes Tubes / Valves 7 24th November 2008 03:44 AM
Group buy for very low jitter oscillators jwb Group Buys 2 27th January 2008 10:17 PM
Triode strapped heptode? ilimzn Tubes / Valves 7 25th December 2005 10:54 PM
Two oscillators replaced by one? Ola Digital Source 2 2nd June 2004 07:44 PM


New To Site? Need Help?

All times are GMT. The time now is 06:49 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki