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

Quanghao Audio Design Quanghao Audio Design is a producer of DIY Audiophile Kits and PCB boards, selected from many listening tests!

Reply
 
Thread Tools Search this Thread
Old 5th September 2018, 11:33 AM   #431
Jezza56 is offline Jezza56  Australia
diyAudio Member
 
Join Date: Sep 2010
Hi Ray,
Great news I have got sound...lol... although it isn't very loud but I hope there may be something we can do to increase output..... it turns out that the input + and - labels are wrong on the board so I was basically shorting out the board to ground through the input rca. Is there anything I can do to increase the output.

Regards

Jerry.
Attached Images
File Type: jpg DSC_0560.jpg (274.1 KB, 55 views)
File Type: jpg DSC_0565.jpg (260.2 KB, 50 views)
  Reply With Quote
Old 5th September 2018, 03:28 PM   #432
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by Jezza56 View Post
Is there anything I can do to increase the output.
There isn't any way to significantly increase the gain of the tube circuit.
Is your step-up transformer x10 gain? What is your cartridge's nominal output?

Last edited by rayma; 5th September 2018 at 03:48 PM.
  Reply With Quote
Old 5th September 2018, 10:25 PM   #433
Jezza56 is offline Jezza56  Australia
diyAudio Member
 
Join Date: Sep 2010
Hi Ray, my MC output is 0.5 mv and transformer is 10 times si
O I will have to get larger step up.
  Reply With Quote
Old 5th September 2018, 10:28 PM   #434
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by Jezza56 View Post
Hi Ray, my MC output is 0.5 mv and transformer is 10 times si
O I will have to get larger step up.
That really should be enough gain. How about the gain in your line stage and power amp?
  Reply With Quote
Old 5th September 2018, 10:57 PM   #435
Jezza56 is offline Jezza56  Australia
diyAudio Member
 
Join Date: Sep 2010
I will try the phono on my Denon tonight as the yamaha amp is from the early 90s and let you know. I will double check the stepup output as i did buy it second hand and the original owner was not pleased with its performance.
  Reply With Quote
Old 5th September 2018, 11:13 PM   #436
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by Jezza56 View Post
I will double check the stepup output as i did buy it second hand and the original
owner was not pleased with its performance.
The step-up should have enough gain to allow normal volume with any associated equipment.
  Reply With Quote
Old 7th September 2018, 02:43 PM   #437
Jezza56 is offline Jezza56  Australia
diyAudio Member
 
Join Date: Sep 2010
Hi Ray, I purchased an oscilloscope today and although I don't understand a lot about them yet it did allow me to observe voltages a bit better. I don't have a test record so just used normal lps and it seems I am not getting any more than 2 to 3Mv out of the step up transformer. I have a project Phono box from which I set to MM and plugged output into my phono stage then into an amplifier and it works fine although there are 2 RIAA circuits in play instead of one as the project box has its own RIAA circuit also. To achieve normal volume the phono stage needs 4.5Mvs so I am thinking I will need a pair of Lundahl LL1941 although I still don't know why the MC1 does not provide enough gain as it specs suggest it to be 1:12.9. The MC1 spec states 47Kohms for input impedance where the phono is 50Kohms does this have any bearing on gain.
  Reply With Quote
Old 7th September 2018, 05:32 PM   #438
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by Jezza56 View Post
used normal lps and it seems I am not getting any more than 2 to 3Mv out of the step up transformer.
You are measuring about right. There should be enough gain with the step-up and one phono stage.
All the specs are fine. Please don't start buying things, because you need to determine the problem.
Do you have a mm cartridge to try, or a different step-up?
  Reply With Quote

Reply


OLD THREAD Hi-end phono preamplifier by Andrea CiuffoliHide 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
OLD THREAD DAC End by Andrea Ciuffoli quanghao Quanghao Audio Design 2063 21st March 2015 09:25 AM
Hi-end phono preamplifier quanghao Quanghao Audio Design 8 30th June 2010 03:37 AM
The DAC End 2 by Andrea Ciuffoli pcb + most parts... prooptiki Swap Meet 7 31st May 2010 02:21 AM
Custom designed transformer for Andrea Ciuffoli 6c33c OTL AMP.... zxcxz Tubes / Valves 2 10th July 2009 04:14 PM
Andrea Ciuffoli Mosfet Amp DieterD Solid State 16 24th December 2001 05:56 AM


New To Site? Need Help?

All times are GMT. The time now is 04:51 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki