Loud HUMMMM

popthree · April 16th, 2007, 12:25 PM

i just bought an old solid state VOX Royal Guardsman from an estate. I got it working somewhat, but after playing it for about 15-30 minutes something went wrong and now there is an awful HUM that comes through the speakers. its so loud it sounds like it would damage the speakers if i continued to leave it running. i can hear the guitar signal along with the awful hum.

what is likely to be wrong ? blown capacitor(s) ?

popthree · April 17th, 2007, 02:41 PM

..

Wally · April 17th, 2007, 05:41 PM

Very likely a cap problem. Turn all controls to zero...is the hum still there?

popthree · April 17th, 2007, 06:52 PM

Quote:

Originally Posted by Wally

Very likely a cap problem. Turn all controls to zero...is the hum still there?

yes it is

Wally · April 17th, 2007, 07:24 PM

It is time for a full service. The electrolytics need replacing minimum, imho.
Soem folks advise bringing up old unused amps/caps slowing on a Variac in order to reform them. I am not a big fan of trying to resuscitate old caps. I would not run the amp until it has been gone through and 'made whole'.
What cab and speakers are with that one. Very likely to be Silver Bulldogs...Celestion Alnicos...if they are original.

popthree · April 17th, 2007, 07:43 PM

do you know what they are ?

Wally · April 17th, 2007, 07:58 PM

Oh, yes, those are Celestion Alnicos. Very nice. Those may be worth what you gave for the amp. IMHO, they are the best part of that amp. They do not have the 'Silver Bulldog' on them, which was a Thomas Organ Co. label. the Celestions that I have pulled out of a Super Beatle (wrecked) were labelled 'Silver Bulldog'. Thomas Organ co. USA built the SS Vox amps. This was a major problem for Vox England, who had thought they had signed a distribution agreement with Thomas Organ Co. Thomas Organ Co. felt free to build amps and sell with the Vox badge. The SS Vox amps fared poorly due to lack of reliability...I won't get into the tube vs SS debate here. Thomas did build a couple of tube amps...Berkeley, Cambridge...but most of their Voxes were SS, including the Super Beatle and your Royal Guradsman.
Trivia...what hit did The Royal Guardsmen have?
You will find some number codes on the frame and the speaker cone which will clue you in to what Celesetion model those are. Get 'em back to me and I'll look them up in my Marshall Amp book.

popthree · April 17th, 2007, 10:54 PM

hey Wally, thanks alot ! i'll pop the back off that cab again tomorrow or next day and try and find the numbers. I did notice the frame of the speakers had 'made in england' stamped in them

when you say the cones, does that mean i'll need to remove the speaker to see the code ?

i didn't pay much for the amp (100 bucks). it was an estate thing, and they didn't have a cable to connect the head to cabinet, so it was unknown if it worked.

cosmetically, its not in bad shape, and should clean up nicely. i really have no use for this monster, so eventually, perhaps after i get the head repaired, i hope to trade it for something i can use....maybe a (much) smaller amp, maybe a tele.

Wally · April 18th, 2007, 11:52 AM

pop.3, you won't have to remove the speaker to see the code on the cone.
The code will be ink-stamped in white ink somewhere on the 'backside' of the cone. On second thought, you probably will find a bulldog on that label.
The 'T' number that will probably be on the frame tells you what model of speaker it is. EX: my Bulldogs are T1656 speakers...they have the H1777 lead cone. There is also a 20W notation, LB20W, stamped on the frame.
The speaker cone number is a date code...which I don't understand and the Marshall book doesn't explain thoroughly...only that the longer it is the older the speaker. Mine is a long number 18 102 003. The 003 at the end designates a lead cone.
You got a bargain. IMHO, the speakers are the treasure.

popthree · April 18th, 2007, 05:44 PM

Quote:

Originally Posted by Wally

Trivia...what hit did The Royal Guardsmen have?

Snoopy vs the Red Baron !!

i had to google that info, but i do now remember the song. funny.

Wally · April 18th, 2007, 05:50 PM

I could remember the little ditty of a tune but the lyrics escaped me. I guess the 'inspiration' came to them in front of Saturday morning TV. hahaha
What would we do without pop music....

popthree · April 18th, 2007, 07:55 PM

i dont see anything on the cones. there is a sticker on the frame: 33-5070-6-B does that compute ?

Wally · April 19th, 2007, 12:12 AM

Mike, the cone codes may be harder to see...mine has the cone code near the connectors so it is on the topside of the speaker as it is installed. I have to get a mirror to read it in the amp in which I have it. Luckily, I have its mate in a box so I can read things a bit more easily on it.
That sticker code is probably a Thomas Organ Co. label. Mine reads
33 5105 6 on that label. Somewhere on the frame will be ink-stamped Celestion codes...a 'T' with a four digit number. Mine is on one 'leg' of the basket.

popthree · April 19th, 2007, 12:25 AM

ok, i did find the cone codes. same on both speakers. 13/102/003.

popthree · April 19th, 2007, 12:44 AM

i took a peek under the dust cover. man, thats some magnet

http://www.tdpri.com/telephoto/data/500/medium/24.jpg

here's the whole monster

http://www.tdpri.com/telephoto/data/500/medium/15.jpg

April 16th, 2007, 12:25 PM	#1 (permalink)
popthree Friend of Leo's Join Date: Jan 2005 Location: Sand Springs, Okay ? Age: 44 Posts: 3,771 52 Photos	Loud HUMMMM i just bought an old solid state VOX Royal Guardsman from an estate. I got it working somewhat, but after playing it for about 15-30 minutes something went wrong and now there is an awful HUM that comes through the speakers. its so loud it sounds like it would damage the speakers if i continued to leave it running. i can hear the guitar signal along with the awful hum. what is likely to be wrong ? blown capacitor(s) ? __________________ http://www.reverbnation.com/thebonanzalunchbox

April 17th, 2007, 02:41 PM	#2 (permalink)
popthree Friend of Leo's Join Date: Jan 2005 Location: Sand Springs, Okay ? Age: 44 Posts: 3,771 52 Photos	.. __________________ http://www.reverbnation.com/thebonanzalunchbox

April 17th, 2007, 07:43 PM	#6 (permalink)
popthree Friend of Leo's Join Date: Jan 2005 Location: Sand Springs, Okay ? Age: 44 Posts: 3,771 52 Photos	do you know what they are ? __________________ http://www.reverbnation.com/thebonanzalunchbox

April 17th, 2007, 10:54 PM	#8 (permalink)
popthree Friend of Leo's Join Date: Jan 2005 Location: Sand Springs, Okay ? Age: 44 Posts: 3,771 52 Photos	hey Wally, thanks alot ! i'll pop the back off that cab again tomorrow or next day and try and find the numbers. I did notice the frame of the speakers had 'made in england' stamped in them when you say the cones, does that mean i'll need to remove the speaker to see the code ? i didn't pay much for the amp (100 bucks). it was an estate thing, and they didn't have a cable to connect the head to cabinet, so it was unknown if it worked. cosmetically, its not in bad shape, and should clean up nicely. i really have no use for this monster, so eventually, perhaps after i get the head repaired, i hope to trade it for something i can use....maybe a (much) smaller amp, maybe a tele. __________________ http://www.reverbnation.com/thebonanzalunchbox

April 18th, 2007, 07:55 PM	#12 (permalink)
popthree Friend of Leo's Join Date: Jan 2005 Location: Sand Springs, Okay ? Age: 44 Posts: 3,771 52 Photos	i dont see anything on the cones. there is a sticker on the frame: 33-5070-6-B does that compute ? __________________ http://www.reverbnation.com/thebonanzalunchbox

April 17th, 2007, 05:41 PM	#3 (permalink)
Wally Poster Extraordinaire Join Date: Mar 2003 Location: Lubbock, TX Posts: 6,443	Very likely a cap problem. Turn all controls to zero...is the hum still there?

April 17th, 2007, 07:24 PM	#5 (permalink)
Wally Poster Extraordinaire Join Date: Mar 2003 Location: Lubbock, TX Posts: 6,443	It is time for a full service. The electrolytics need replacing minimum, imho. Soem folks advise bringing up old unused amps/caps slowing on a Variac in order to reform them. I am not a big fan of trying to resuscitate old caps. I would not run the amp until it has been gone through and 'made whole'. What cab and speakers are with that one. Very likely to be Silver Bulldogs...Celestion Alnicos...if they are original.

April 17th, 2007, 07:58 PM	#7 (permalink)
Wally Poster Extraordinaire Join Date: Mar 2003 Location: Lubbock, TX Posts: 6,443	Oh, yes, those are Celestion Alnicos. Very nice. Those may be worth what you gave for the amp. IMHO, they are the best part of that amp. They do not have the 'Silver Bulldog' on them, which was a Thomas Organ Co. label. the Celestions that I have pulled out of a Super Beatle (wrecked) were labelled 'Silver Bulldog'. Thomas Organ co. USA built the SS Vox amps. This was a major problem for Vox England, who had thought they had signed a distribution agreement with Thomas Organ Co. Thomas Organ Co. felt free to build amps and sell with the Vox badge. The SS Vox amps fared poorly due to lack of reliability...I won't get into the tube vs SS debate here. Thomas did build a couple of tube amps...Berkeley, Cambridge...but most of their Voxes were SS, including the Super Beatle and your Royal Guradsman. Trivia...what hit did The Royal Guardsmen have? You will find some number codes on the frame and the speaker cone which will clue you in to what Celesetion model those are. Get 'em back to me and I'll look them up in my Marshall Amp book.

April 18th, 2007, 11:52 AM	#9 (permalink)
Wally Poster Extraordinaire Join Date: Mar 2003 Location: Lubbock, TX Posts: 6,443	pop.3, you won't have to remove the speaker to see the code on the cone. The code will be ink-stamped in white ink somewhere on the 'backside' of the cone. On second thought, you probably will find a bulldog on that label. The 'T' number that will probably be on the frame tells you what model of speaker it is. EX: my Bulldogs are T1656 speakers...they have the H1777 lead cone. There is also a 20W notation, LB20W, stamped on the frame. The speaker cone number is a date code...which I don't understand and the Marshall book doesn't explain thoroughly...only that the longer it is the older the speaker. Mine is a long number 18 102 003. The 003 at the end designates a lead cone. You got a bargain. IMHO, the speakers are the treasure.

April 18th, 2007, 05:50 PM	#11 (permalink)
Wally Poster Extraordinaire Join Date: Mar 2003 Location: Lubbock, TX Posts: 6,443	I could remember the little ditty of a tune but the lyrics escaped me. I guess the 'inspiration' came to them in front of Saturday morning TV. hahaha What would we do without pop music....

April 19th, 2007, 12:12 AM	#13 (permalink)
Wally Poster Extraordinaire Join Date: Mar 2003 Location: Lubbock, TX Posts: 6,443	Mike, the cone codes may be harder to see...mine has the cone code near the connectors so it is on the topside of the speaker as it is installed. I have to get a mirror to read it in the amp in which I have it. Luckily, I have its mate in a box so I can read things a bit more easily on it. That sticker code is probably a Thomas Organ Co. label. Mine reads 33 5105 6 on that label. Somewhere on the frame will be ink-stamped Celestion codes...a 'T' with a four digit number. Mine is on one 'leg' of the basket.

April 19th, 2007, 12:25 AM	#14 (permalink)
popthree Friend of Leo's Join Date: Jan 2005 Location: Sand Springs, Okay ? Age: 44 Posts: 3,771 52 Photos	ok, i did find the cone codes. same on both speakers. 13/102/003. __________________ http://www.reverbnation.com/thebonanzalunchbox

April 19th, 2007, 12:44 AM	#15 (permalink)
popthree Friend of Leo's Join Date: Jan 2005 Location: Sand Springs, Okay ? Age: 44 Posts: 3,771 52 Photos	i took a peek under the dust cover. man, thats some magnet http://www.tdpri.com/telephoto/data/500/medium/24.jpg here's the whole monster http://www.tdpri.com/telephoto/data/500/medium/15.jpg __________________ http://www.reverbnation.com/thebonanzalunchbox

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