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RCA 816 MV

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Posted on May 11, 2020 at 11:36:01
Iain42
Reviewer

Posts: 895
Location: Arcansaw
Joined: February 10, 2004
 I am using RCA 816's in two DIY builds. Do they really need a warm-up? I've read contrary reports some say you do some say you do not.

thanks









High sensitivity, wide dynamic range, low distortion, and smooth frequency response. Pwk

http://www.itishifi.com

 

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RE: RCA 816 MV, posted on May 11, 2020 at 13:10:46
6bq5
Audiophile

Posts: 4385
Location: SF Bay
Joined: August 16, 2001
 Typically all vacuum tube based circuits need some warm up -
or perhaps more accurately time for voltages to stabilize after turn on-

This should not take hours - but could take more than a few minutes depending upon the circuit -

There is also an issue of thermal stability - which for a tube like the 816 could be a few minutes more than an EL-34, or two...
Happy Listening

 

RE: RCA 816 MV, posted on May 11, 2020 at 15:08:58
Paul Joppa
Industry Professional

Posts: 7295
Location: Seattle, WA
Joined: April 23, 2001
 IIRC, it's a matter of getting and keeping the temperature inside the envelope in the right range for the pool of mercury. Read the data sheet.

 

RE: RCA 816 MV, posted on May 11, 2020 at 20:32:28
Iain42
Reviewer

Posts: 895
Location: Arcansaw
Joined: February 10, 2004
 Thanks it looks like I'll be adding warm-up switches.



High sensitivity, wide dynamic range, low distortion, and smooth frequency response. Pwk

http://www.itishifi.com

 

RE: RCA 816 MV, posted on May 11, 2020 at 20:34:29
Iain42
Reviewer

Posts: 895
Location: Arcansaw
Joined: February 10, 2004
 Thanks... Mt first buids used slow start damper diodes. Nothing like a slow start of a minute.


High sensitivity, wide dynamic range, low distortion, and smooth frequency response. Pwk

http://www.itishifi.com

 

RE: RCA 816 MV, posted on May 12, 2020 at 05:05:09
dave slagle
Manufacturer

Posts: 5430
Location: NYC
Joined: April 27, 2001
 This blurb is interesting at the end of the data sheet. Not sure exactly how to interpret it but it does seem to suggest exactly the opposite of what everyone else says about MV tubes. In this case it suggests shielding the tube *from* external RF fields and not the more common AARL mention *from emitting* them.





WRT the condensed mercury temp, I remember reading in a Northern Electric mercury thyratron data sheet that when used in the arctic special care needed to be taken to assure a minimum bulb temperature for the mercury and I seem to recall if being just above 110º. The addition of argon to the mercury was found to stabilize the firing voltage range. It was also suggested if that temperature is reached and maintained, the filament was no longer required. This made me want to try a heat wrap and a "cold cathode" 83 :-)

dave

 

RE: RCA 816 MV, posted on May 12, 2020 at 19:48:03
Iain42
Reviewer

Posts: 895
Location: Arcansaw
Joined: February 10, 2004
 That is crazy so that means you should definately do it.

I'm just gonna as ad an extra switch 8-)


High sensitivity, wide dynamic range, low distortion, and smooth frequency response. Pwk

http://www.itishifi.com

 

RE: RCA 816 MV, posted on May 13, 2020 at 20:10:02
TomWh
Audiophile

Posts: 764
Location: Tucson Az
Joined: August 7, 2003
 I would really be interested in the sound difference between the damper and the MV's. I run dampers every where.

Thanks Tom

 

RE: RCA 816 MV, posted on May 13, 2020 at 20:17:49
Iain42
Reviewer

Posts: 895
Location: Arcansaw
Joined: February 10, 2004
 I honestly don't expect them to sound any better. Those TV damper diodes are pretty bad ass. I just want a little blue glow and merc flavor.



High sensitivity, wide dynamic range, low distortion, and smooth frequency response. Pwk

http://www.itishifi.com

 

RE: RCA 816 MV, posted on May 14, 2020 at 15:51:30
GEO
Audiophile

Posts: 4749
Joined: April 7, 2000
Contributor
  Since: September 9, 2000
 I used 6AX4. Then started favoring AZ1s

 

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