Canuck Audio Mart Hifi and Audio ForumCanuck Audio Mart Hifi and Audio Forum
It is currently Mon Dec 10, 2018 4:37 pm

All times are UTC - 8 hours




Post new topic Reply to topic  [ 250 posts ]  Go to page Previous  1 ... 13, 14, 15, 16, 17
Author Message
PostPosted: Thu Dec 06, 2018 7:18 am 
Offline
User avatar

Joined: Tue Jun 17, 2008 4:50 pm
Posts: 12546
Location: Toronto, ON, CA
I prefer PRP and Caddock. PRP is very close to the caddock in sound. Some don't like that sort of dry/clean sound. They think it sterile.

_________________
I'm sure that the term "resolving" has way more to do with a sense of self worth than any scientific principle. - davinci_redux


Top
 Profile  
Reply with quote  
PostPosted: Thu Dec 06, 2018 7:44 am 
Offline

Joined: Wed Sep 14, 2005 11:47 am
Posts: 4103
Location: Ottawa, ON, CA
jst_canuck wrote:
This graph of noise voltage in resistors is from your reference https://www.eetimes.com/document.asp?doc_id=1278251
Current Noise is the dominant source below 1,000 Hz.
Above 1,000 Hz Thermal Noise is dominant.

Do you consider this as an issue compared to audio frequency noise that is generated within a tube or a semiconductor :?:

Is component noise a real problem, in any pragmatic sense, where audio stage gain is low :idea:


I'm certainly no expert - that's why I was asking questions.
But I would say the most significant contributor to an amp's distortion is the
noise on the power supply rails.
Try plugging in an electric drilll, switching it on, and watch the rectified 120 Hz on a scope - it jitters all over the place.
This ends up causing spiking noise on the DC rails.
This is why Nakamichal puts so much emphasis on designing the power supply.
So noise doesn't end up being modulated by the gain devices
even if the amp has a good PSRR.

Also, I've found that Hydro earth is quite noisy.
Hence the reason to lift analog ground.
Also using star ground is important to minimize noise.

I don't have any equipment to measure noise.
However, the equations say that only resistance can cause noise.
This suggests that resistors are a bigger contributor to noise than gain devices.

From listening I agree that resistors contribute more noise - but both are important.
Certainly, a bi polar transistor designed for audio use sounds miles better than a basic switching transistor.
But linearity may come into play as well.
Also, in the front end of an F5, I'd say a quality metal film resistor sounds miles
better than a basic carbon one.

On thing to stress though - the addition of boutique components should be the last step
in any design and their use should be minimized.

.


Top
 Profile  
Reply with quote  
PostPosted: Thu Dec 06, 2018 10:45 am 
Online

Joined: Sat Sep 01, 2012 5:08 am
Posts: 834
Location: Montréal, QC, CA
Frank Wang wrote:
Uunderhill wrote:
Frank - it sounds like you approach resistors from a Quality Control point of view.
If were to ask about metal film vs tantalum resistors on a certain DIY Audio site, the wolves would circle.

.....
In foil resistors, the terminals and the resistive element are parts of the same piece of the foil,
so this problem is avoided. [/i]

First the functional requirements, such as power rating and etc...need check against the datasheet, this is the dominant factor. Then comes personal preference, which maker, product....
Just like we buy cars, first need clear out the functional requirement, e.g. sedan, SUV, pickup or van... all wheel drive or front or back...diesel, Hybrid or gas...then, pick the maker, model, color and etc...
Uunderhill, as Frank just said, the choice of a resistor is firstly power requirement dependent.

This means that the choice depends where the resistor is in the amplification chain.
By example, for phono preamp or R2R DAC, the power is ultra low. Ultra low noise resistors are then preferred.

For output stage OTOH, the resistor intrinsic noise % is almost irrelevant before other factor like thermal stability.
Thus, the driver stage is where we have the largest choice for resistor. No need ultra low noise or high power ones.
It's then the ideal spot to give the amp its sonority by using such or such resistor.

_________________
Keep things simple and even simpler

Balance MC-1010 phono stage... in progress (week 2)


Top
 Profile  
Reply with quote  
PostPosted: Sat Dec 08, 2018 10:28 am 
Offline

Joined: Wed Sep 14, 2005 11:47 am
Posts: 4103
Location: Ottawa, ON, CA
Thanks for everyone's input concerning types of resistors.

I had not realized that Tantalum ( TaN ) other metal film resistors (NiCr ?)
are both thin film resistors and are made using a vacuum plating process.

Nakamichael's comment about having low noise resistors early in the voltage gain section
is quite important - because any noise from them gets amplified by the next stages.

Also Frank made a good comment about adding boutique components to a poor design
is a total waste of time.

.


Top
 Profile  
Reply with quote  
PostPosted: Sat Dec 08, 2018 9:52 pm 
Offline

Joined: Fri Jul 04, 2014 8:37 pm
Posts: 354
Location: Toronto, ON, CA
Uunderhill wrote:
Thanks for everyone's input concerning types of resistors.

I had not realized that Tantalum ( TaN ) other metal film resistors (NiCr ?)
are both thin film resistors and are made using a vacuum plating process.

Nakamichael's comment about having low noise resistors early in the voltage gain section
is quite important - because any noise from them gets amplified by the next stages.

Also Frank made a good comment about adding boutique components to a poor design
is a total waste of time.

.


There is no simple answer as it's complicated as there is human factor. There are so many audiophile "myths", sometimes we play with parts just because other people say they are good...sometimes we found our version of the "truth"...sometimes because those parts look good or feel good...

From engineering perspective, the parts should serve/meet the design purpose, I'm no professional, just some shallow understandings and observations. For normal cases, e.g. don't know what to use, just go with the common ones...as I mentioned above, based on technical data in the datasheet...for resistors, datasheet not only indicating power rating (given temperature), also many other technical data.
There are some interesting cases where we DIYers get excited, one typical place is coupling caps (in SS amps for example if there is any), if don't know what to use just go with commonly used stuffs, e.g. Elna RFS, Nichicon Muse BP, i.e. audio caps...you can get these information (what caps are suitable for coupling) from many places : 1. Data sheet sometimes has application notes; 2. Factory machines (for example, the Marantz PM7000 which I restored years ago, I found it used Elna Silmic as coupling caps, actually Marantz quite fond of Elna caps;-); 3. Whatever other people says...LOL
About datasheet, below is an example, you can get a lot of information when you choosing parts...even more complicated is that good numbers on datasheet doesn't mean good sound...so what's wrong?
https://www.vishay.com/docs/28325/021asm.pdf
Ok, once you get parts meet functional/technical requirements, you get a working machine. If you are happy then it's done, lucky you! If not...there is no perfect thing in audiophile, it's all about compromise...(might be perfect for someone, but not for other people)...;therefore some tuning (or mods) coming in...if the sound is too bright, might swap in some warm sound parts...could be warm sound caps, or less harsh resistors...ignore the fact that you might just introduced distortion to get warm sound...and if lucky enough to get to the point, might "resolve" the issue. Here, I'm not against those antique or pricey fancy stuffs, just saying once lay down the foundation, before you swap in anything, need ask if there is any "problem" and what you are trying to achieve, don't go blindly as people say they are warm sound so use them everywhere...
I normally don't encourage this discussion, as there is no simple correct answer...kind of "personal" actually...personal tastes/preferences, experience...to name a few...don't want go too deep as it will be endless. Tuning/mods might or might not bring any difference, even if bring difference, might be good or bad...

A real story:
Couple of years ago, a friend of mine build a pair of SEAS drivers speaker, the kit from madisound used ClarityCap ESA caps...after listening for a while...he spend $$$ to get some V-Caps as they are fancy and pricey...so should be better than ESA caps. After he swap the caps, he found V-Caps sound dark and got disappointed...I have a rule for myself - I won't spend money on caps more expensive than speakers, I did try to stop him before he made the purchase but failed ...so I comforted him that at least learned something. I believe V-Cap is good in some applications, but not good everywhere...the same for any other fancy or not fancy stuffs.
What "surprised" me was a couple of weeks later, my friend said he now think his speaker sound better with V-Caps...maybe the caps need break-in...or maybe his ears got used to the sound ...who knows...and as long as he is happy...it's all that matter...


Top
 Profile  
Reply with quote  
PostPosted: Sun Dec 09, 2018 5:59 am 
Offline
Premium User
User avatar

Joined: Fri Mar 06, 2015 3:01 pm
Posts: 382
Location: CAMBRIDGE, ON, CA
+1
Frank Wang wrote:
Uunderhill wrote:
Thanks for everyone's input concerning types of resistors.

I had not realized that Tantalum ( TaN ) other metal film resistors (NiCr ?)
are both thin film resistors and are made using a vacuum plating process.

Nakamichael's comment about having low noise resistors early in the voltage gain section
is quite important - because any noise from them gets amplified by the next stages.

Also Frank made a good comment about adding boutique components to a poor design
is a total waste of time.

.


There is no simple answer as it's complicated as there is human factor. There are so many audiophile "myths", sometimes we play with parts just because other people say they are good...sometimes we found our version of the "truth"...sometimes because those parts look good or feel good...

From engineering perspective, the parts should serve/meet the design purpose, I'm no professional, just some shallow understandings and observations. For normal cases, e.g. don't know what to use, just go with the common ones...as I mentioned above, based on technical data in the datasheet...for resistors, datasheet not only indicating power rating (given temperature), also many other technical data.
There are some interesting cases where we DIYers get excited, one typical place is coupling caps (in SS amps for example if there is any), if don't know what to use just go with commonly used stuffs, e.g. Elna RFS, Nichicon Muse BP, i.e. audio caps...you can get these information (what caps are suitable for coupling) from many places : 1. Data sheet sometimes has application notes; 2. Factory machines (for example, the Marantz PM7000 which I restored years ago, I found it used Elna Silmic as coupling caps, actually Marantz quite fond of Elna caps;-); 3. Whatever other people says...LOL
About datasheet, below is an example, you can get a lot of information when you choosing parts...even more complicated is that good numbers on datasheet doesn't mean good sound...so what's wrong?
https://www.vishay.com/docs/28325/021asm.pdf
Ok, once you get parts meet functional/technical requirements, you get a working machine. If you are happy then it's done, lucky you! If not...there is no perfect thing in audiophile, it's all about compromise...(might be perfect for someone, but not for other people)...;therefore some tuning (or mods) coming in...if the sound is too bright, might swap in some warm sound parts...could be warm sound caps, or less harsh resistors...ignore the fact that you might just introduced distortion to get warm sound...and if lucky enough to get to the point, might "resolve" the issue. Here, I'm not against those antique or pricey fancy stuffs, just saying once lay down the foundation, before you swap in anything, need ask if there is any "problem" and what you are trying to achieve, don't go blindly as people say they are warm sound so use them everywhere...
I normally don't encourage this discussion, as there is no simple correct answer...kind of "personal" actually...personal tastes/preferences, experience...to name a few...don't want go too deep as it will be endless. Tuning/mods might or might not bring any difference, even if bring difference, might be good or bad...

A real story:
Couple of years ago, a friend of mine build a pair of SEAS drivers speaker, the kit from madisound used ClarityCap ESA caps...after listening for a while...he spend $$$ to get some V-Caps as they are fancy and pricey...so should be better than ESA caps. After he swap the caps, he found V-Caps sound dark and got disappointed...I have a rule for myself - I won't spend money on caps more expensive than speakers, I did try to stop him before he made the purchase but failed ...so I comforted him that at least learned something. I believe V-Cap is good in some applications, but not good everywhere...the same for any other fancy or not fancy stuffs.
What "surprised" me was a couple of weeks later, my friend said he now think his speaker sound better with V-Caps...maybe the caps need break-in...or maybe his ears got used to the sound ...who knows...and as long as he is happy...it's all that matter...

_________________
8) My View of me - Audiophile on a mission!!!
:roll: Wife's View of me - Audiophile on a budget!!!


Top
 Profile  
Reply with quote  
PostPosted: Sun Dec 09, 2018 6:57 am 
Offline

Joined: Wed Sep 14, 2005 11:47 am
Posts: 4103
Location: Ottawa, ON, CA
No doubt that datasheets, equations and test measurements are the major part of design.

But also I to listen circuit changes, and search for a physics explanation
or take measurements to explain why there may be any sonic differences.

Noise equations explain why a basic carbon composition resistor sounds different
than a metal film.
But I haven't found a satisfactory answer to explain the sonic difference between TaN and NiCr.
At audio frequencies, I tend to think of a resistor as a pure resistor in series with various
noise generators.
It may well be that the TaN resistor has a different noise spectrum than the NiCr
and that spectrum is better at masking other more objectionable noise
Specifically the TaN may be better at masking power supply spiking noise and distortion from a digital source.
But I have no evidence to support this.
Also the metal tantalum is highly corrosion resistant, and IMO oxide on the surface of a conductor
causes harshness - so this may come into play as well.

In terms of a CCS - I was quite surprised that the type of CCS used in a circuit
has an impact on the sonics.
In a previous discussion ( page 15) , Nakamichal provided the explanation of why.
Recall, I posted the schematic for the Aleph J on the first page of this forum.
The Aleph J uses a Zener diode and a bi polar transistor to form a CCS.
However, IMO this type of CCS sounds awful - Back to Back audio bi polars sound miles better.
and an improvement over this is a jFET with a resistor which makes quite a good CCS.
Simple measurements show that a jFET and resistor make quite a good CCS.

In terms of tube circuits, sadly a triode will not form a CCS like a jFET does,
but rather a pentode is needed - Augh !

In terms of the power diodes,
when the secondary of a transformer stores energy in a magnetic field, and diodes switch it off,
ringing occurs at a frequency created by the leakage inductance of the transformer
and the capacitance created between the windings.
Knowing this, the ringing can be search for and found using a scope.
Adding a snubber network between the secondaries and the power diodes helps.
Erik pointed out an article called "Simple No-Math Transformer Snubber using Quasimoto Test Jig" - which is a pdf file.

Also, I read the regular silicon diode bridge was fine
and I considered boutique diodes to be a waste of money.
However, Nakamichal pointed these out to me - HFA15PB60PbF
https://www.mouser.ca/datasheet/2/196/h ... 226131.pdf
which have quite good reverse recovery characteristics.
But I bought these. HFA08TB60PbF
https://www.mouser.ca/datasheet/2/196/h ... 225300.pdf

.


Last edited by Uunderhill on Sun Dec 09, 2018 7:18 am, edited 1 time in total.

Top
 Profile  
Reply with quote  
 Post subject: Another M2
PostPosted: Sun Dec 09, 2018 7:14 am 
Offline

Joined: Fri Jul 04, 2014 8:37 pm
Posts: 354
Location: Toronto, ON, CA
Another M2 for a domestic friend...usual process...
-Parts use paper to mount around 1mm above PCB...so air can flow, and in case of disaster won't damage the PCB;
-Legs bend toward each other and form a contact with solder pads... around 45 degree...can bend legs away from each other also...point is bend to form a contact between legs and solder pads;
-Solder iron power/temperature, soldering time are also important...not enough then the flux residual inside solder joints, too much then the oxidation...
-Solder one leg of the part...move on to next part...later on come back to finish all legs...so parts won't get overheated...
-Gold plated solder pads...for big ones, heat the solder pads first...then move to the joint...


Attachments:
File comment: use couple of layers of paper to separate the parts from PCB
IMG_6983.jpg
IMG_6983.jpg [ 167.38 KiB | Viewed 76 times ]
File comment: Bent legs 45 degree toward each other...legs form a contact with solder pads.
IMG_6986.jpg
IMG_6986.jpg [ 181.82 KiB | Viewed 76 times ]
IMG_6992.jpg
IMG_6992.jpg [ 224.83 KiB | Viewed 76 times ]
IMG_7033.jpg
IMG_7033.jpg [ 218.84 KiB | Viewed 76 times ]
IMG_7040.jpg
IMG_7040.jpg [ 186.01 KiB | Viewed 76 times ]
File comment: Dent matches dent...
IMG_7042.jpg
IMG_7042.jpg [ 168.09 KiB | Viewed 76 times ]
IMG_7052.jpg
IMG_7052.jpg [ 331.39 KiB | Viewed 76 times ]
Top
 Profile  
Reply with quote  
 Post subject: Re: Another M2
PostPosted: Sun Dec 09, 2018 7:55 am 
Offline
Moderator
User avatar

Joined: Tue Feb 22, 2005 2:06 pm
Posts: 5245
Location: Montreal, QC, CA
Sadly, not my usual process. :(

Frank Wang wrote:
...usual process...
-Parts use paper to mount around 1mm above PCB...so air can flow, and in case of disaster won't damage the PCB;
-Legs bend toward each other and form a contact with solder pads... around 45 degree...can bend legs away from each other also...point is bend to form a contact between legs and solder pads;
-Solder iron power/temperature, soldering time are also important...not enough then the flux residual inside solder joints, too much then the oxidation...
-Solder one leg of the part...move on to next part...later on come back to finish all legs...so parts won't get overheated...
-Gold plated solder pads...for big ones, heat the solder pads first...then move to the joint...


But it will be in future. Thanks Frank !!


Top
 Profile  
Reply with quote  
 Post subject: Re: Another M2
PostPosted: Mon Dec 10, 2018 9:32 am 
Offline

Joined: Fri Jul 04, 2014 8:37 pm
Posts: 354
Location: Toronto, ON, CA
Toby wrote:
Sadly, not my usual process. :(
.....
But it will be in future. Thanks Frank !!


As long as make sense to you...thanks Toby.

Seems Plitron is out of retail business after sold to ACAL...don't do online store to retail buyers anymore...

So, Amplimo it is...2*225VA just arrived.


Attachments:
opened.jpg
opened.jpg [ 201.44 KiB | Viewed 18 times ]
IMG_7062.jpg
IMG_7062.jpg [ 220.38 KiB | Viewed 21 times ]
Untitled.jpg
Untitled.jpg [ 197.32 KiB | Viewed 21 times ]
Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 250 posts ]  Go to page Previous  1 ... 13, 14, 15, 16, 17

All times are UTC - 8 hours


Who is online

Users browsing this forum: Nakamichel, Whstoon and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group