Go Back   Home > Forums > >

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

Sound advice !
Sound advice !
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
Old 14th September 2021, 05:22 PM   #21
Cagomat is offline Cagomat  Germany
diyAudio Member
 
Join Date: Dec 2005
Location: Nürnberg
Quote:
Originally Posted by Brian28 View Post
Guys .. be gentle ..I’m a mechanical engineer ..🤷 ..and I can build the amp from the drawings but fault finding is the real art ..

I have attached the schematic with some Ac voltages and DC .. please let me know what else you need .. can you make it simple as well

Cheers Brian
the 14V AC on the anode of 300b is way too low. Please control the wiring of your monolit output transformer, and measure the inductance of the primary winding
  Reply With Quote
Old 14th September 2021, 05:25 PM   #22
Brian28 is offline Brian28
diyAudio Member
 
Join Date: Jun 2020
Quote:
Originally Posted by TheGimp View Post
It looks like the C3Mis amplifying properly.

You have 114VAC at the grid of the 300B.

However you only have 10.4VAC on the plate of the 300B.

You should be approaching clipping with at least 200VAC on the plate.

Something appears to be wrong with the load on the 300B.
Hi , where does the load on the plate come from ? .. OPT ?
  Reply With Quote
Old 14th September 2021, 05:31 PM   #23
Cagomat is offline Cagomat  Germany
diyAudio Member
 
Join Date: Dec 2005
Location: Nürnberg
yes the opt primary
  Reply With Quote
Old 14th September 2021, 06:07 PM   #24
AndreK is offline AndreK  United States
diyAudio Member
 
Join Date: Mar 2004
Location: New Jersey
Sound advice !
Brian,
Are you sure your OPT primary connected to 300B, not secondary?
  Reply With Quote
Old 14th September 2021, 06:15 PM   #25
Cagomat is offline Cagomat  Germany
diyAudio Member
 
Join Date: Dec 2005
Location: Nürnberg
Its a little bit confusing, the voltage across the primary winding is 15v the dc resistance of the Monolite opt is 105 ohm. 15V/105 ohm is 146 ma.
  Reply With Quote
Old 14th September 2021, 09:10 PM   #26
Brian28 is offline Brian28
diyAudio Member
 
Join Date: Jun 2020
Ok ,been in the workshop for a few hours checking everything again .. how about a schoolboy error �� .I seem to have labelled up the pins on the 300b’s incorrectly..
what a knob ��.
I have rewired and fired it up again .. now there seems to be much more volume on the workshop speaker ….I’m going to fire it up again tomorrow and check the voltages again and perhaps try it again on my system ..
I’m hoping that’s the problem ..
  Reply With Quote
Old 15th September 2021, 05:50 AM   #27
Diabolical Artificer is offline Diabolical Artificer  United Kingdom
diyAudio Member
 
Diabolical Artificer's Avatar
 
Join Date: May 2014
Location: UK
Quote:
I seem to have labelled up the pins on the 300b’s incorrectly..
what a knob
Easily done, I've executed some right howlers, away with the faeries, brain only running on one cylinder.


Good your making progress, Andy.
  Reply to this post

Reply


Sound advice !Hide this!Advertise here!
Thread Tools

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
Sound, sound beautiful sound Atk1d Tubelab 2 23rd April 2014 02:23 PM
Need some advice where to install LED, also power socket advice. Mull3t Construction Tips 14 28th May 2012 04:32 PM
Sound, Sound, and more Sound - Instractables Nordic Everything Else 0 5th March 2008 05:43 PM
"Sound Advice" for Class D jackinnj Class D 0 4th May 2005 01:19 PM
Poster in Musical Instrument forum needs bridging advice on BrianGT 4780 advice moving_electron Chip Amps 0 16th February 2005 12:37 AM


New To Site? Need Help?

All times are GMT. The time now is 08:40 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki