Rectifier mechanical buzz

regal · 12th June 2011, 09:22 AM

My pair of JJ Matsushita 5AR4 supplying my SSHV's have developed a mechanical buzz after around 1000 hrs. The SSV is set for 60 mA each channel, the power transformers are hammonds 269JX, the transformers are not buzzing or hot.

I've had good luck with JJ's in the past but, I think I am going to source a pair of japanese 5AR4's.

Sound lke the right decision?

SY · 12th June 2011, 10:45 AM

Are the rectifiers feeding a C input filter? If so, how big is the C?

regal · 12th June 2011, 11:56 AM

50 uf to 1.5k resistor to 5uf to SSHV . Shouldn't be too much capacitance, No issues show up with PSUD. The problem wasn't there at first. Going to try some Japanese 5AR4, if it is still there I'll dig deeper. I just don't remember ever having a retifier buzz/hum mehanically, hence the post.

DigitalJunkie · 12th June 2011, 12:09 PM

50uf might be a bit much.IIRC the datasheet states 40uf as the maximum.
Maybe try a 33uf cap after the rectifier instead, and see if that helps.

regal · 12th June 2011, 12:42 PM

My original post has a typo, these are just plain JJ new 5ar4's withh 1k hours on them. The datasheet from JJ claim 60 uf, but I can certainly try lower.

http://lib.store.yahoo.net/lib/thetu.../JJ-GZ34-S.pdf

Eli Duttman · 12th June 2011, 03:19 PM

As Philips owned both Mullard and Amperex, I'd say this data sheet is reasonably definitive. It shows a max. I/P cap. value of 60 μF.

Unfortunately, JJ has come to stand for "Jamona Junk", far too often. The OP's experience may be 1 more example of the phenomenon.

As the fact that Matsushita made their 5AR4s with Mullard tooling is quite well known, those tubes carry hefty price tags. I suggest you contact a reliable tube vendor, like Jim McShane and purchase a properly culled Chinese or Russian specimen.

DigitalJunkie · 13th June 2011, 05:56 AM

My bad,I think I was thinking of the 5U4.

regal · 13th June 2011, 06:23 AM

Wow didn't realize how expensive Matsu 5AR4s had gotten but I found a decent deal on NOS 80's Hitachi 5AR4's, going to try them.

Thanks

nigelwright7557 · 13th June 2011, 09:36 PM

Quote:

Originally Posted by regal

Wow didn't realize how expensive Matsu 5AR4s had gotten but I found a decent deal on NOS 80's Hitachi 5AR4's, going to try them.

Thanks

You could buy a lot of SS diodes for $15 !

Eli Duttman · 13th June 2011, 11:48 PM

Quote:

Originally Posted by nigelwright7557

You could buy a lot of SS diodes for $15 !

It depends on the SS diode in question. A 1200 PIV/5 A. silicon carbide Schottky by Cree costs 8 USD.

12th June 2011, 09:22 AM	#1
regal diyAudio Member Join Date: Jan 2004 Location: MD	Rectifier mechanical buzz My pair of JJ Matsushita 5AR4 supplying my SSHV's have developed a mechanical buzz after around 1000 hrs. The SSV is set for 60 mA each channel, the power transformers are hammonds 269JX, the transformers are not buzzing or hot. I've had good luck with JJ's in the past but, I think I am going to source a pair of japanese 5AR4's. Sound lke the right decision?

12th June 2011, 10:45 AM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Are the rectifiers feeding a C input filter? If so, how big is the C? __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

12th June 2011, 03:19 PM	#6
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	As Philips owned both Mullard and Amperex, I'd say this data sheet is reasonably definitive. It shows a max. I/P cap. value of 60 μF. Unfortunately, JJ has come to stand for "Jamona Junk", far too often. The OP's experience may be 1 more example of the phenomenon. As the fact that Matsushita made their 5AR4s with Mullard tooling is quite well known, those tubes carry hefty price tags. I suggest you contact a reliable tube vendor, like Jim McShane and purchase a properly culled Chinese or Russian specimen. __________________ Eli D.

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12th June 2011, 11:56 AM	#3
regal diyAudio Member Join Date: Jan 2004 Location: MD	50 uf to 1.5k resistor to 5uf to SSHV . Shouldn't be too much capacitance, No issues show up with PSUD. The problem wasn't there at first. Going to try some Japanese 5AR4, if it is still there I'll dig deeper. I just don't remember ever having a retifier buzz/hum mehanically, hence the post.

12th June 2011, 12:09 PM	#4
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	50uf might be a bit much.IIRC the datasheet states 40uf as the maximum. Maybe try a 33uf cap after the rectifier instead, and see if that helps.

12th June 2011, 12:42 PM	#5
regal diyAudio Member Join Date: Jan 2004 Location: MD	My original post has a typo, these are just plain JJ new 5ar4's withh 1k hours on them. The datasheet from JJ claim 60 uf, but I can certainly try lower. http://lib.store.yahoo.net/lib/thetu.../JJ-GZ34-S.pdf

13th June 2011, 05:56 AM	#7
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	My bad,I think I was thinking of the 5U4.

13th June 2011, 06:23 AM	#8
regal diyAudio Member Join Date: Jan 2004 Location: MD	Wow didn't realize how expensive Matsu 5AR4s had gotten but I found a decent deal on NOS 80's Hitachi 5AR4's, going to try them. Thanks

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