why does a relay attenuator sounds much worst than an alps black ? - Page 3 - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

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 Search this Thread
Old 9th January 2008, 10:34 PM   #21
diyAudio Member
 
Join Date: May 2005
Location: Hungary
Calvin, I need imput impedance higher than about 70k. Some tube ended tuner, RIAA etc. can not be loaded with low value. Of course I could use a buffer (cathode follower makes sense in English ?) at the input, but that is one more tube etc.

I felt it is not really an R-2R (it is R2D2 :-), but did not know exactly. Thanks for the comment, I look after how a real R-2R looks like.

Thanks,

JG
  Reply With Quote
Old 9th January 2008, 10:42 PM   #22
poobah is offline poobah  United States
diyAudio Member
 
poobah's Avatar
 
Join Date: Nov 2005
I would not use anything that says OMRON on it... EVER. ...just my personal experience. OMRON = JUNK.

Here, something like this:

http://www.alliedelec.com/catalog/ca...=&PageNum=1104


  Reply With Quote
Old 9th January 2008, 10:56 PM   #23
diyAudio Member
 
Join Date: May 2005
Location: Hungary
analog_sa, yes, the bandwith is not narrowed for sure,

And yes, the alps was fully open. What you mentioned, to solder the closed contasts together is what I wrote earlier and tried today. It worked. And you are ritgh, I should build it in the line amp, but I did not want to disassemble it yet. If the network will be good with Omron G6K also, that is the next step. If it is not good enough again with G6K, than I give up and try to control a rotary switch.

***
You are in a much better position to find out the reason for the poor sound that any of us.
***
I do what I can and I share it, but I was hoping somebody did this already in tube based chain.

For sure my preference is not the mellow, (I say Linn like :-) too sweet sound character. I like drums, bells, and a wide variety of music. In the other hand I do not like additional distorsion to be added, I think this is what the relay produce. But, maybe I'm wrong and the alps helps to hide something. It is the same in two different systems.

Thanks,

JG
  Reply With Quote
Old 9th January 2008, 11:08 PM   #24
diyAudio Member
 
Join Date: May 2005
Location: Hungary
Bobken, I would be very interested in the remote controllabe volume control you mention !
Thanks,
JG
  Reply With Quote
Old 9th January 2008, 11:18 PM   #25
diyAudio Member
 
Join Date: May 2005
Location: Hungary
I do not have a good soundcard, just the motherboards AD1988 which I do not think can do much on this level. I plan to buy a t.c.electronic konnekt 8, but that is spring time.
Do you think this distorsion (or whatever) would be measureable ? That is a bit strange for me, but I have not measured really with PC yet with good experience.

thanks,

JG
  Reply With Quote
Old 10th January 2008, 12:06 PM   #26
Bobken is offline Bobken  United Kingdom
diyAudio Member
 
Join Date: Dec 2002
Location: UK
Quote:
Originally posted by Giordano
Bobken, I would be very interested in the remote controllabe volume control you mention !
Thanks,
JG

Hi Giordano,

Although I would like to help with this, I am unable to reveal any very specific details of this remote attenuator. It was a design which was commissioned by another UK company, and which will go into production later this year.

One thing I will say, though, is that I 'listened' to many different relays before finalising this top-quality (cost no object) design, and more importantly (destructively) took apart any which were worthwhile using from the 'sonic' aspect, to inspect their internal constructions. This is important to ensure that they enjoy a long service life without any serious sonic detereoration, as I have discovered problems in this regard over the years.

Most relays have internal parts made of dissimilar metals, simply because some parts need to be springy, and others like contacts need to be hard and resistant to arcing, oxidation and wear etc.
Some contact detereoration happens over time even with the best totally-enclosed or inert-gass-filled relays, unfortunately, but this is not the only issue here.

I don't recommend using any relay for this purpose which has any internal parts riveted together, as this can give rise to later problems. All internal parts should ideally be spot-welded or friction-welded, so that there are no metal-to-metal junctions where any corrosion or other fouling can intervene *between* the parent metals.

It is said that whenever parts are securely clenched, crimped or riveted together, this will exclude all possibility of future corrosion as the air is excluded and the parts virtually weld themselves together.
However, this is another less well-appreciated 'theoretical oversight', as I have seen for myself when dissembling some of these relays. Perhaps the makers haven't taken the trouble which I have gone to in inspecting these parts after a period in service! Also, don't forget that many of these relays are originally designed for telecoms usage, but this application may not require the same overall bandwidths which we are interested in here, and in my experience it is important to maintain integrity to many times higher than our normal upper hearing threshold.

If you carefully separate the parts and inspect the junctions through which the signal needs to pass, there will frequently be some very obvious discolouration/oxidation or whatever, which is highly resistive, and non-linear in this regard. It cannot be seen until the parts are separated, and I believe this results from galvanic reactions, or something similar, when currents pass though dissimilar metal 'junctions', but whatever the reasons for this, the result is undesirable.

Incidentally, one Omron relay I tried was up with the best, and this was their High-Isolation G6A-BS series, with bifurcated (dual) contacts OK for use down to 10uA @10mV DC, and max. contact resistance of merely 50mOhm. These are rather noisy, only from the mechanical aspect, when they switch, resulting from the more positive switching and higher contact pressures used than in some other relays, but this is good for the audio sound, though. They are not suitable for high current applications.

Another quite good choice is the Panasonic DS Series.

Regards,
__________________
Bob
  Reply With Quote
Old 10th January 2008, 01:41 PM   #27
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally posted by poobah
Look for relays that say "telecom" or "dry circuit" in the description. Then look at the specs carefully... when you are looking at the right style of relay... the data sheet should list the MINIMUM current the relay is capable of switching.

The best relay would probably be a mercury wetted reed. I don't know if they are still available though... with mercury and the envoronment issues to consider.

Mercury wetted relays can still be found on EBay. These are really remarkable devices used for signal switching.


Like incandescent bulbs, we will have to stock up on these gems.

(I wonder if the luminaries in the U.S. Congress have figured that replacing incandescents with other devices is going to cause a "mercury in the landfill" problem.)
  Reply With Quote
Old 10th January 2008, 05:09 PM   #28
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
HP (Agilent) used the Omron G6AK-274P relay in the relay board for the HP3488 -- they have Gold-Silver contacts.
  Reply With Quote
Old 10th January 2008, 05:15 PM   #29
poobah is offline poobah  United States
diyAudio Member
 
poobah's Avatar
 
Join Date: Nov 2005
I know Jack... and I know that OMRON is what keeps the trains running on time in Japan... and they DO run on time.

My experience has been that the typical omron part falls apart in your hands... before you even get it near a circuit board.

Mercury wetted would be perfect for this... but he would have to double up on relays and modify the drive strategy a bit as the wetteds don't seem to come SPDT / form C arrangements.

Newark and everybody still has them... I think that the amount of mercury and the method of containment may offer some exemption?

  Reply With Quote
Old 10th January 2008, 05:57 PM   #30
Bobken is offline Bobken  United Kingdom
diyAudio Member
 
Join Date: Dec 2002
Location: UK
[QUOTE]Originally posted by poobah

My experience has been that the typical omron part falls apart in your hands... before you even get it near a circuit board.

Hi,

Precisely which parts fail when these relays "fall apart", please?

I have had 24 of them performing without a hitch for around 14 months now in a prototype, and the Omron G6 range is one of the hardest of these types of relays to even get into.

There are no external parts, and in fact I needed to saw the entire top off carefully with a razor saw to get into one, to inspect its internal construction. Even with the top removed which substantially impairs the structural rigidity of the package, I can stand on it without any damage occurring.

Regards,
__________________
Bob
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
PCM converters, ALPS black beauty 10k abzug Swap Meet 1 16th October 2007 02:45 AM
FS: Alps Black Beauty Volume Pot davidhs Swap Meet 3 22nd March 2007 01:20 AM
WTT: Alps Black Beauty 2x250kLog for lower... kasra Swap Meet 0 5th March 2005 08:00 AM
FS. Alps Black Beauty balance pots Mark Hathaway Swap Meet 0 20th April 2003 03:01 AM


New To Site? Need Help?

All times are GMT. The time now is 01:22 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2