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 28th February 2010, 11:42 AM   #961
audiodesign is offline audiodesign  Italy
Banned
 
Join Date: Sep 2005
Send a message via MSN to audiodesign OLD THREAD DAC End by Andrea Ciuffoli
Here distortion spectrum and noise of the DAC End 2.

The 50Hz peak at -62dB is present because I still have no chassie.
Attached Images
File Type: gif DACEnd2_5687_0dB_thd1.gif (52.5 KB, 547 views)
  Reply With Quote
Old 28th February 2010, 12:05 PM   #962
apelizzo is offline apelizzo  Australia
diyAudio Member
 
apelizzo's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by gabanyayaya View Post
So that meant no new parts or value need to be added, just reroute the solder track according to 6H6P spec right....




But what about the voltage? Do I need to reduce to 150V-0 , 0.2mA and 9v-0, 1.5A since I'm going to use 6H6P not E182CC or 5687 (250V 50mA/9v 3A)...?
You only need to reroute the socket. Leave everything else the same. Because you preparing the bed for the 6n6P I recommend you to try the 6n6T which is a Chinese copy of the Russian 6n6P. The letter "T' is important and stands for Top quality. The Chinese 6n6 (without "T") most of the time has mismatch units inside the single tube. But the 6n6T be confident that the two units inside are matched. The sound of the 6n6T I believe is the best, I don't mean is the best quality tube, just the sound.

Last edited by apelizzo; 28th February 2010 at 12:15 PM.
  Reply With Quote
Old 28th February 2010, 01:24 PM   #963
le´flu is offline le´flu  Germany
diyAudio Member
 
Join Date: Mar 2004
Location: Hoexter
Hello Quang Hao, Andrea and all,
is there some kind of toslink-inputstage you would
recommend for this projekt?
I need optical-input for my computer-audio-device.

Greetigs Ulf
  Reply With Quote
Old 28th February 2010, 04:29 PM   #964
gabanyayaya is offline gabanyayaya  Malaysia
diyAudio Member
 
Join Date: Aug 2008
Quote:
Originally Posted by adamus View Post
looking at the datasheet no changes necessary. the curves are very similar to the 5687. Just the appropriate rerouting needed.

I would say though many people prefer the 6n6p running at more than 8ma. I like at least 15
In the data sheet 6H6P needs around 28mA but I've seen people use up to 100mA for B+. Wont this be a waste....? What exactly the suitable traffo for 6H6P?
  Reply With Quote
Old 28th February 2010, 04:33 PM   #965
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
just run it the same as the 5687, it will be fine.

With the B+ at 270 audiodesign has picked a reasonable operating point, so unless you want to seriously change things then i would do as apelizzo suggests, and stick with same components. same transformer.

heres the datasheet

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

Last edited by adamus; 28th February 2010 at 04:52 PM.
  Reply With Quote
Old 1st March 2010, 12:04 AM   #966
apelizzo is offline apelizzo  Australia
diyAudio Member
 
apelizzo's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by gabanyayaya View Post
In the data sheet 6H6P needs around 28mA but I've seen people use up to 100mA for B+. Wont this be a waste....? What exactly the suitable traffo for 6H6P?
As I agree with adamus,
6n6p, 5687, E182CC are all very close. So you don't need to change anything on the board unless you want to change setup.
So the 6n6p can handle max 20mA per unit when units are both working. With 100mA definitely will destroy the tube. Using 7.5mA each tube is not a waste. Remember that DAC is a source of signal and you need to keep the noise figure as low as possible. Low current through the tube reduces the noise and you still have low impedence output because the nature of the tube. The noise is generated by the amount of electrons hitting the plate in the same way when rain falls on a metal roof. If the rain is heavy the roof is noisier. Sometimes it rains and you cannot hear it. The tube is a "musical instrument" the sound also depends on how the plate vibrates when electron hit the surface. Caracteristic of the sound also varies with the current. So you need to find the balance, by experimenting, between noise figure and sound performance and the "sound of the plate".
I hope it helps.

Last edited by apelizzo; 1st March 2010 at 12:21 AM.
  Reply With Quote
Old 1st March 2010, 11:39 AM   #967
gabanyayaya is offline gabanyayaya  Malaysia
diyAudio Member
 
Join Date: Aug 2008
Quote:
Originally Posted by adamus View Post
just run it the same as the 5687, it will be fine.

With the B+ at 270 audiodesign has picked a reasonable operating point, so unless you want to seriously change things then i would do as apelizzo suggests, and stick with same components. same transformer.

heres the datasheet

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

Quote:
Originally Posted by apelizzo View Post
As I agree with adamus,
6n6p, 5687, E182CC are all very close. So you don't need to change anything on the board unless you want to change setup.
So the 6n6p can handle max 20mA per unit when units are both working. With 100mA definitely will destroy the tube. Using 7.5mA each tube is not a waste. Remember that DAC is a source of signal and you need to keep the noise figure as low as possible. Low current through the tube reduces the noise and you still have low impedence output because the nature of the tube. The noise is generated by the amount of electrons hitting the plate in the same way when rain falls on a metal roof. If the rain is heavy the roof is noisier. Sometimes it rains and you cannot hear it. The tube is a "musical instrument" the sound also depends on how the plate vibrates when electron hit the surface. Caracteristic of the sound also varies with the current. So you need to find the balance, by experimenting, between noise figure and sound performance and the "sound of the plate".
I hope it helps.

Duly noted

Thanks both of you guys for the advice
  Reply With Quote
Old 1st March 2010, 01:07 PM   #968
apelizzo is offline apelizzo  Australia
diyAudio Member
 
apelizzo's Avatar
 
Join Date: Sep 2006
Adamus,
today i received the new 5687 tubes. The heater power supply is not strong enough and I experienced the relay chattering because the regulator has not enough headroom so it passes AC.

Could you please measure your bridge rectifier AC input and the bridge DC output before the 2 power resistors. I can't believe this bridge becomes so hot and with 9.3V AC in gives 10.18V DC output , only x1.1 with 1.4A load (1.55V voltage drop on each 2.2R)

I'm not happy about the E182CC microphonics and I would like to test the 5687 if I can get rid of the issue. Can you give me your feedback about this issue. Appreciated

Thanks

Last edited by apelizzo; 1st March 2010 at 01:17 PM.
  Reply With Quote
Old 1st March 2010, 01:53 PM   #969
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
I sorted my chattering by dropping the 2.2r to 1r, and the 1k to 700r.



Try just dropping less through the resistors, or get rid of them entirely and jumper, just watch the heat on the reg.

Edit - just noticed i misread your post. I'll whip the cover off and measure for you. Give me ten mins.

Last edited by adamus; 1st March 2010 at 02:22 PM.
  Reply With Quote
Old 1st March 2010, 02:04 PM   #970
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
vac = 8.9
vdc after rectifier = 9
v drop over the power resistors = 0.9v
v after resistors = 8.1v

I am just within the regulation limits for the regulator. 6.5v out and its not regulating. 6.3 and it is. For reliability i should really remoe the power resistors completely, my ac line has horrible variation on it.
AC ripple on heater supply = less than 1mv

and my recitifer is HOT HOT HOT, i never tchecked this comp for heat, its go to be the hottest part. operating temp is upto 150c though.

Last edited by adamus; 1st March 2010 at 02:20 PM.
  Reply With Quote

Reply


OLD THREAD DAC End 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 Hi-end phono preamplifier by Andrea Ciuffoli quanghao Quanghao Audio Design 438 22nd September 2018 11:14 AM
Cleo: End to End 24bit 192khz USB DAC with tube output bcherry DIY HiFi Supply 7 3rd July 2010 11:15 PM
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 06:08 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki