YAHA HELP - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

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 26th July 2013, 10:30 PM   #1
prezden is offline prezden  Canada
diyAudio Member
 
Join Date: Nov 2008
Default YAHA HELP

I've built this YAHA but can't get to work.
There is power going to the board but absolutely nothing happens. The bottom side is kind of messed up from changing some components when it didn't work.
I'm hoping someone can spot something that I'm missing and it's not another screwed up project
Attached Images
File Type: jpg yaha t.jpg (376.3 KB, 168 views)
File Type: jpg yaha b.jpg (317.5 KB, 162 views)
  Reply With Quote
Old 26th July 2013, 10:47 PM   #2
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
Sorry but have you a schematic or at least some information on it, or where we can find information on it please?
__________________
www.flyingmole.co.uk For World Wide support for Flying Mole, Class D, Refurbishment and Repairs. www.jonsnell.co.uk
  Reply With Quote
Old 26th July 2013, 11:08 PM   #3
prezden is offline prezden  Canada
diyAudio Member
 
Join Date: Nov 2008
Here are the specs for it- thanks
Attached Files
File Type: pdf YAHA_v2 Head Amplifier.pdf (547.9 KB, 84 views)
  Reply With Quote
Old 26th July 2013, 11:20 PM   #4
diyAudio Member
 
Avro Arrow's Avatar
 
Join Date: Sep 2010
Location: Toronto, eh
Where did R5 go?
  Reply With Quote
Old 26th July 2013, 11:39 PM   #5
prezden is offline prezden  Canada
diyAudio Member
 
Join Date: Nov 2008
I thought R5 was optional. It's not on the photo of the finished amp. When I first built it I had R5 on the board and then took them off when it didn't work.
  Reply With Quote
Old 27th July 2013, 12:22 AM   #6
dfy is offline dfy
diyAudio Member
 
Join Date: Jun 2013
Quote:
Originally Posted by prezden View Post
I thought R5 was optional. It's not on the photo of the finished amp.
Pretty sure it is on that photo. It's just not mounted on the board - it's one of the two resistors hanging in the air next to the tube socket.
  Reply With Quote
Old 27th July 2013, 12:36 AM   #7
prezden is offline prezden  Canada
diyAudio Member
 
Join Date: Nov 2008
ok I'll put 5 back on and try again

Thanks
  Reply With Quote
Old 27th July 2013, 12:44 AM   #8
dfy is offline dfy
diyAudio Member
 
Join Date: Jun 2013
Also, I'm really not sure about that "mod" to the heater supply described in your PDF. The original YAHA article has this set up as a 300mA constant current supply. With the "mod" described in the first schematic in your file, it seems to represent a 1.5V voltage supply. That doesn't seem great to me, just like the resistor values are mixed up or something (do wait for a more qualified opinion on that though before randomly swapping parts - but the wiring diagram above the photo in your PDF seems to confirm my suspicion).

edit: Also, I think the red lines in the wiring diagram are meant to be wire jumpers. (some of those extra holes can also hold the R7/C3 mod) Those are not connected on your board at all! So, for example, your tube cathode isn't grounded, but completely floating.

edit2: The silkscreen on your PCB also seems strange. The slot that says R2L (next to the caps) would be the perfect place for R1R, and indeed the wiring diagram in the PDF seems to suggest that R1R should go there. (but from cap to ground, so you're still one hole off) That description/schematic/board/etc is just very inconsistent.

Last edited by dfy; 27th July 2013 at 01:08 AM.
  Reply With Quote
Old 27th July 2013, 01:49 AM   #9
prezden is offline prezden  Canada
diyAudio Member
 
Join Date: Nov 2008
There seems to be a bare wire from the 2 ac connections. Any idea what that's all about?
  Reply With Quote
Old 27th July 2013, 02:22 AM   #10
dfy is offline dfy
diyAudio Member
 
Join Date: Jun 2013
What AC connections? This amp is supposed to run off 12V DC!
(The two bare wires are probably the GND connection from the audio input GND to power supply GND, as well as one of the switch connections (that one is 'live', i.e. at 12V, during operation though).
  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
YAHA with output buffer: need help TB Headphone Systems 3 25th August 2010 04:17 PM
hummming YAHA frajavcar Tubes / Valves 0 1st July 2008 05:58 AM


New To Site? Need Help?

All times are GMT. The time now is 04:43 PM.


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