Go Back   Home > Forums > >

His Master's Noise: A Thoroughly Modern Tube Phono Preamp
His Master's Noise: A Thoroughly Modern Tube Phono Preamp
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 25th February 2021, 09:55 AM   #661
FJC Corpas is offline FJC Corpas  Spain
diyAudio Member
 
Join Date: Jan 2009
Quote:
Originally Posted by TasoTaso View Post
Hi what is this FFT software? Have tambien a hardware?
Gracias!
I am using MI (Multi-Instrument). It's very good but a bit expensive. You can achieve similar results with ARTA or SpectraPlus. You could also use REW that it's free, but it is more oriented to loudspeaker measurement. I'm not sure if MI has its own HW, I use an EMU-0404 soundcard.
  Reply With Quote
Old 25th February 2021, 12:03 PM   #662
TasoTaso is offline TasoTaso
diyAudio Member
 
Join Date: Oct 2018
Ok, many thanks
  Reply With Quote
Old 25th February 2021, 12:34 PM   #663
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
His Master's Noise: A Thoroughly Modern Tube Phono Preamp
Quote:
Originally Posted by FJC Corpas View Post

jackinnj, I have several pairs of D3a and the result is similar in all of them, so I guess we can eliminate the valve from the equation. As for the input signal, I think it's a good idea. I will use a higher input voltage and maybe I can avoid the noise limitations of the test equipment.
Here's a comparison of D3a's
Attached Images
File Type: gif D3a_Comparison.gif (32.6 KB, 51 views)
  Reply With Quote
Old 26th February 2021, 11:18 AM   #664
FJC Corpas is offline FJC Corpas  Spain
diyAudio Member
 
Join Date: Jan 2009
Wow, one of those D3a's looks really bad! That behaviour is very different from what I get in my measurements. My measurements show a quite clear flicker noise (1/f). In his article, Stuart mentions that "most D3a that I've checked needed some time to burn in before their grid current stabilized". I'm not sure if he was referring to this type of noise or to what? It would be nice if he could intervene in this discussion to shed some light on the subject (and, by the way, make me a bit happy ).

Yesterday I tested my HMV implementation on my sound system. As my EMT tonearm is in the process of being rebuilt, I used a CD player whose output goes to my iRIAA module (which provides an inverse of the curve and additionally an attenuation of 60dB, thus a signal similar to what would come out of an MC cartidge), then the signal goes to the phono and the preamp. I was able to check that nearly everything was fine, excellent sound, zero detectable hum but... I could perceive the noise very clearly... it's like listening to music with the sound of a torrential rain in the background... So I have to fix this so that the phono is usable.

I know there are real tube experts in this community, please don't be shy.... Any suggestions are welcome.

Last edited by FJC Corpas; 26th February 2021 at 11:24 AM.
  Reply With Quote
Old 26th February 2021, 11:51 AM   #665
anystereo is offline anystereo  United States
diyAudio Member
 
Join Date: Apr 2005
Location: Watertown, MA USA
I have had a similar issue and still do. Here’s the details:
My HMN is designed for me SPU which is 2 ohms.
I have pair of sowter 1480 step-ups. In one channel a ‘white noise’ developed after the first few weeks, after switching tubes from each channel the white noise stayed with the channel. When I switched cartridges to a dl103 which is 40 ohms. The white noise went away. On top of this I had serious microphonics until I put in some isolation and damping. Rubber gaskets around each tube and foam padding - not perfect yet but way better. The sound dampening is on order. Occasionally it breakouts into full on shrill oscillation, - this went away when I changed cartridges. The SPU needed a rebuild for mechanical reasons and be back in a few months.
My current understanding is that the white noise is really a form of oscillation and that the fact that only in one channel is probably related to wiring. Because the SPU is ‘prewired’ and the tone arm is also I don’t see an opportunity to switch the leads to further chase down the issue. The ‘white noise’ may get worse again when I replace the SPU. I’ll let you know, until then I’ll enjoy the dl103 which sounds fantastic with only a little snow in one channel , - if only a little light on the low end. The snow ain’t hum, - hum!
  Reply With Quote
Old 26th February 2021, 12:26 PM   #666
FJC Corpas is offline FJC Corpas  Spain
diyAudio Member
 
Join Date: Jan 2009
The SPU is a wonderful cartidge but difficult to amplify properly. I own several and the key is usually in the step-up transformer.

When you talk about white noise I assume you mean Johnson or thermal noise (which does indeed have the white noise pattern). Are you sure you have this type of noise? Have you been able to measure it? Johnson noise and flicker noise are not the same thing. Johnson noise is constant at all frequencies (power spectral density = cte) whereas flicker noise increases with decreasing frequency (pink noise pattern). The former has been widely studied and understood while the latter is somewhat more enigmatic.

Last edited by FJC Corpas; 26th February 2021 at 12:37 PM.
  Reply With Quote
Old 26th February 2021, 03:54 PM   #667
anystereo is offline anystereo  United States
diyAudio Member
 
Join Date: Apr 2005
Location: Watertown, MA USA
I am not sure what kind of noise it is but am thinking because it is only in one channel that it can be eliminated with some effort. The other channel is completely quiet even with headphones which is encouraging.
The breakout into shrill oscillation only happens now when the case is mechanically disturbed, like tapping on it or moving it. The rubber gaskets on each tube was simple and effective.

As baseline I tried my Pass Pearl One. Which is dead quiet with the sowter 1480 step-ups. So the problem seems to be down stream from the step-ups. Maybe a noisy ccs semiconductor?
  Reply With Quote
Old 26th March 2021, 03:53 PM   #668
anystereo is offline anystereo  United States
diyAudio Member
 
Join Date: Apr 2005
Location: Watertown, MA USA
Found a cold solder joint on the negative heater supply, boy was that noise inducing!

Does anyone have a pcb for the voltage regulators that's for sale?
  Reply With Quote
Old 26th March 2021, 03:56 PM   #669
tvicol is offline tvicol  Europe
diyAudio Member
 
tvicol's Avatar
 
Join Date: Jan 2005
Location: Bucharest
His Master's Noise: A Thoroughly Modern Tube Phono Preamp
You may use my gerbers, posted in this thread. Will cost you ~2$ to make the boards + shipping.

Regards,
Tibi
__________________
https://evotronix.eu
  Reply With Quote
Old 26th March 2021, 05:44 PM   #670
tvicol is offline tvicol  Europe
diyAudio Member
 
tvicol's Avatar
 
Join Date: Jan 2005
Location: Bucharest
His Master's Noise: A Thoroughly Modern Tube Phono Preamp
Here is another BOM with almost all parts from mouser.

Mouser Electronics

Regards,
Tibi
__________________
https://evotronix.eu
  Reply With Quote

Reply


His Master's Noise: A Thoroughly Modern Tube Phono PreampHide 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
Low noise transistor and noise figure Real_Macgyver Solid State 28 27th July 2012 09:42 AM
noise planarboy Analogue Source 2 11th February 2008 08:06 AM
Still have noise. pjanda1 Chip Amps 40 17th March 2006 03:16 PM
Help with noise davidlzimmer Chip Amps 25 5th March 2006 09:39 PM
Noise Bukitoo Analogue Source 2 17th March 2004 02:37 PM


New To Site? Need Help?

All times are GMT. The time now is 02:45 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