Personal Tube Amp DIY Project - Page 3 - 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 10th December 2009, 01:11 AM   #21
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
TA,

6GW8s are scarce. If you have NOS in your pile, sell them to partially fund your project.

May I immodestly suggest "El Cheapo". You can get 12 very honest WPC from an EC built with Dynaclone Z565 O/P trafos and operating in ultralinear mode. Triode wired "finals" (as shown) are good for 6 sweet WPC. Any 6V6 family tube works with the parts values shown. Saratov, Russia, made "reissue" TungSol 6V6s have shown themselves to be at least the equal of the remaining NOS.

IMO, it's a good thing when an amp you plan on using for a while employs tubes that are currently being produced.
Attached Images
File Type: gif elCheapo-23jun06-map.gif (38.8 KB, 168 views)
__________________
Eli D.
  Reply With Quote
Old 11th December 2009, 12:01 AM   #22
diyAudio Member
 
Join Date: Nov 2009
Location: Texas
I like the El Chepo. I am going to build it. Do you have a parts list by chance? I want to by an assorment of caps for audio dyi projects, what is a good capacitor for audio. The Mullard 6GW8 tube that was is my Newcomb model ED 10C when I bought it is the only one I have. I started playing with it last night and it looks like the filment winding on the p/s transformer is shorted. I do want to play with this one so I am going to start looking for another transformer.

matt
  Reply With Quote
Old 11th December 2009, 03:40 AM   #23
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Matt,

Jim McShane will sell you all the parts you need to build an "El Cheapo", except magnetics and casework. Jim's site is here.

If you can find the money, buy Dynaclone Z565 O/P trafos from Triode Electronics. The price/performance ratio of the Z565 is very hard to better.

If something less expensive is necessary, buy Edcor's CXPP25-6-7.6K model. The guitar amp O/P trafo shown in the drawing has (sadly) ceased to be a bargain.

Allied Electronics has a full set of power magnetics. Stock # 967-2343 is the Triad N-77U main B+ trafo. Stock # 227-0034 is the 6K27VF B- and 12AT7 heater trafo. Stock # 967-1004 is a Triad C-24X filter choke. Stock # 967-8019 is a Triad VPS24-1800, whose 2X "12" V. windings take care of O/P tube + 12AL5 heater power and B+ boost.

Oh yeah, the LENGTHY saga of "El Cheapo" is here.
__________________
Eli D.
  Reply With Quote
Old 11th December 2009, 07:57 AM   #24
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Quote:
Originally Posted by TexasAudio View Post
I like the El Chepo. I am going to build it. Do you have a parts list by chance? I want to by an assorment of caps for audio dyi projects, what is a good capacitor for audio.

matt
Buy Russian caps on ebay, teflon for instance. A lot of info can be found on this board.
You can also use soviet 6V6 tubes in the El Cheapo to keep it cheap and still sounding good.
And I suppose you could use the 6n1p tube at the front :-)

Last edited by Jaap; 11th December 2009 at 08:01 AM.
  Reply With Quote
Old 11th December 2009, 01:42 PM   #25
diyAudio Member
 
Join Date: Dec 2003
Location: Midwest
I dug around my parts box, and found an old (cheap) 1960s console stereo amplifier. It has almost the equivalent schematic to your Emerson, using 12AX7 driver and 50EH5 pentodes driven in SE through tiny little cheap transformers for about 1.4 Watts/channel.

Naturally, it doesn't have a transformer. The power cord solders directly onto the circuit board. It's a deathtrap! Zap!

Anyway, I figure I can rebuild this thing for a few dollars:

1. Replace the old film capacitors with ones from Parts Express (i.e. Solen, Jantzen, or Dayton Audio). A few dollars.
2. Google "Type FP" three-section capacitor, and there are several vendors offering a replacement type at reasonable cost ($10-$12).
3. Buy a 1:1 isolation transformer.

Voila! You may want to consider the same strategy instead of a wholesale redesign. The 50EH5 with those tiny SE transformers will retain the 60's sound - for better or worse - and you don't have to worry about reconfiguring the chassis layout for larger tubes, components, and power dissipation - and designing a new circuit.
  Reply With Quote
Old 11th December 2009, 02:22 PM   #26
diyAudio Member
 
Join Date: Dec 2003
Location: Midwest
Even better, I've been looking for 120:110 isolation transformers to power old equipment. Power in the 1960s was about 110VAC. Modern utility power is about 122VAC. The 10% higher voltage stresses the filaments, possibly capacitors, and increases plate current. The Hammond 169C looks about perfect for the job, providing line isolation while simultaneously reducing the voltage to 1960's standards. The 169C costs about $50, about the same you'd pay for a power transformer anyway.

Replacement 50EH5 tubes are cheap ($5-10) from a variety of sources. Yours still may have some life. With a SE design, you don't worry as much about asymmetrical aging as PP designs.

Last edited by Kashmire; 11th December 2009 at 02:33 PM.
  Reply With Quote
Old 11th December 2009, 11:50 PM   #27
Cassiel is offline Cassiel  Libya
diyAudio Member
 
Cassiel's Avatar
 
Join Date: Sep 2004
Location: Madrid
Hi K,

You may find this page interesting:

Audion visits Wu Flingpoo

The schematic link is at the bottom of the page. 1960s console stereo amplifier modded by Joe Rosen.
__________________
Do your best and don't worry.
  Reply With Quote
Old 12th December 2009, 12:26 AM   #28
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Quote:
I suppose you could use the 6n1p tube at the front
No go! There's a big difference between μ=60 (12AT7) and μ=33 (6Н1П). "El Cheapo" is an "integrated" amp. A line stage is not needed for CDP signal sources. Also, the NET harmonic distortion spectrum will be adversely affected, if another type is substituted for the 12AT7.

SY likes JJ's current production 'T7s. Mullard made NOS can be had for about $25.
__________________
Eli D.
  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
Personal Planars. tade Planars & Exotics 19 28th March 2010 03:11 AM
Your own personal TradeMark Steerpike Construction Tips 3 19th November 2009 12:06 AM
quick update on my personal HT room project JinMTVT Multi-Way 1 18th August 2008 03:55 AM
My OLD Project....... cheap tube audio project!!! tube-lover Tubes / Valves 4 8th May 2008 10:26 PM
personal jobs rumors Tubes / Valves 10 2nd April 2007 10:03 AM


New To Site? Need Help?

All times are GMT. The time now is 11:50 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