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

Tubelab Discussion and support of Tubelab products, prototypes and experiments

Reply
 
Thread Tools Search this Thread
Old 13th October 2017, 04:34 AM   #1
Cifte12AU7 is offline Cifte12AU7  United States
diyAudio Member
 
Join Date: Oct 2017
Location: Chicago, IL
Default Help with my board! R26

My R26 is literally touching my tube socket V21 pin no. 5 on the PC board. That freaked me out because R16 is not touching V11 pin no. 5 on the board.

I noticed this just as I was getting ready to solder the R26 location in question.

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


I looked at George's website and several of his photos look like the solder on the back of the board is touching at R26 and V21 pin no. 5. But I'm confused, because wouldn't the design require symetry on the other side of the amp (i.e. at R16 V11 pin no. 5)?

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


Or am I not seeing this right?

Please help! I had a great, calm and methodical process going on--absolutely enjoying this project. And I don't want to go further until I figure it out. I'm wondering if I'm just not understanding the layout or if my printed pc board is off a bit.

Thanks much!
  Reply With Quote
Old 13th October 2017, 05:11 AM   #2
Cifte12AU7 is offline Cifte12AU7  United States
diyAudio Member
 
Join Date: Oct 2017
Location: Chicago, IL
A close up R26 overlapping v21 pin no. 5.

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.
  Reply With Quote
Old 13th October 2017, 01:34 PM   #3
PDL is offline PDL  United States
diyAudio Member
 
Join Date: Jan 2010
Location: Minneapolis
Can you please attach the photos to the forum and not use photobucket?

I and many others can't see them.
  Reply With Quote
Old 13th October 2017, 02:26 PM   #4
Cifte12AU7 is offline Cifte12AU7  United States
diyAudio Member
 
Join Date: Oct 2017
Location: Chicago, IL
Click the image to open in full size.
  Reply With Quote
Old 13th October 2017, 02:28 PM   #5
Cifte12AU7 is offline Cifte12AU7  United States
diyAudio Member
 
Join Date: Oct 2017
Location: Chicago, IL
Click the image to open in full size.
  Reply With Quote
Old 13th October 2017, 02:35 PM   #6
Cifte12AU7 is offline Cifte12AU7  United States
diyAudio Member
 
Join Date: Oct 2017
Location: Chicago, IL
Click the image to open in full size.
  Reply With Quote
Old 13th October 2017, 02:53 PM   #7
w5jag is offline w5jag  United States
diyAudio Member
 
Join Date: Feb 2007
Location: Arkansas
R26 and R16 are low value resistors, 100 ohms, placed in series with the control grid of the power tube, as a precautionary measure for the purpose of suppressing possible parasitic oscillations in the power tube, under unusual operating conditions.

Pin 5 is the control grid of the power tubes.

Other than the remote possibility of some excess heat being physically transferred to the resistor, and possibly compromising its lifespan, I don't see much of a problem with it physically touching the tube socket at pin 5.

Symmetry is pleasing from a builders point of reference, but electrons can't see and it is of no consequence to them in this instance.

I wouldn't worry about it. Just take your time, and enjoy your build. If you have questions, just ask. We all learn that way. Sometimes it may take a bit for somebody to see a question and get back to you on it.

Welcome to the Tubelab forum.

Win W5JAG
  Reply With Quote
Old 13th October 2017, 03:55 PM   #8
Cifte12AU7 is offline Cifte12AU7  United States
diyAudio Member
 
Join Date: Oct 2017
Location: Chicago, IL
W5jag, What a relief! Sorry for the freak out. I was just excited about how smoothly my resistor soldering went that I was scared that my board might have an issue.

THANK YOU!!!! I'd be lost without you guys.
  Reply With Quote
Old 13th October 2017, 11:33 PM   #9
Hannibal 8 is offline Hannibal 8  United States
diyAudio Member
 
Join Date: Feb 2016
Location: Missouri
Mine looks just like yours. This project was my first amp build. The completed amp is on in my studio all day every day and has thousands and thousands of hours on it. I'm currently building one for my son and another for a friend as gifts. It's truly one of the few projects that have given back to me more than I put in. Enjoy.
  Reply With Quote
Old 14th October 2017, 12:52 PM   #10
mkane77g is offline mkane77g  United States
Always Learning
diyAudio Member
 
Join Date: Nov 2014
Location: 100 miles N. of S.F.
Help with my board! R26
And that pcb holder you have is one of those gotta have items.
  Reply With Quote

Reply


Help with my board! R26Hide 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
My Cambridge 500SE, needs an output board (to replace internal DAC Board) slbender Digital Source 1 11th July 2018 02:43 AM
Sure Electronics New Tripath Board 4*100W class-D Amplifier Board 7788q Class D 354 17th March 2017 01:19 PM
JLSounds XMOS USB board + AK4396 board + Direct DSD PCB ravid Swap Meet 1 29th December 2016 11:36 AM
Unknown Board DC12V TPA3116 amplifier board DIY L163-9 AUS Ben Class D 0 8th December 2016 04:05 AM
FS: Ian FIFO i2s-to-PCM board, Single XO clock board trung224 Swap Meet 3 26th November 2016 02:18 PM


New To Site? Need Help?

All times are GMT. The time now is 05:56 AM.


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