I put a bad ouput tube in my amp, did I hurt it?

sbelyo · 27th April 2011, 03:40 PM

I did a dumb thing...

I got a 6AS7 off of ebay, tested it and it only posted like 10 on a scale of 0-120. I wanted to see if I could hear anything out of it anyway so I put it in my Van Waarde design headphone amp flicked the power switch and plugged in my good headphones like an idiot.

I got a load hum out of the left channel and nothing out of the right.

I unplugged the headphone and checked the output with a meter just to make sure that I didn't send a stupid amount of DC to the phones, nope just 20 mV I think

It was at that time that I noticed some noise coming from the choke in the PSU. One side of it was hot to the touch and the other side was cold. I cut the power and pulled the tube.

I put the good tube back in and everything sounds normal but I only listened for 10 minutes so I don't think it had much time to warm up yet.

Do you guys think I hurt anything?

Cassiel · 27th April 2011, 04:09 PM

Quote:

I put the good tube back in and everything sounds normal

Most likely just a little stress, nothing to worry about.

sbelyo · 27th April 2011, 04:28 PM

Quote:

Originally Posted by Cassiel

Most likely just a little stress, nothing to worry about.

That's what I was hoping. I didn't see any smoke or smell anything odd with my nose to the choke.

I'm always warning other's not to do stupid stuff like this, but I forget to listen to myself

carbondated · 27th April 2011, 07:08 PM

Here's something I've always wanted to know - how do you know when a choke is faulty? I hear of chokes becoming 'oversaturated', what happens then?

boywonder · 27th April 2011, 07:18 PM

If none of the tube elements were shorted and it just tested weak, that shouldn't cause any harm.

sbelyo · 27th April 2011, 07:27 PM

Quote:

Originally Posted by boywonder

If none of the tube elements were shorted and it just tested weak, that shouldn't cause any harm.

good, there were no shorts

M Gregg · 27th April 2011, 07:32 PM

Quote:

Originally Posted by carbondated

Here's something I've always wanted to know - how do you know when a choke is faulty? I hear of chokes becoming 'oversaturated', what happens then?

depends on the fault!

If the choke overheats or the back EMF is very high you can get shorted turns this means your power supply will become noisy due to lower henrys. (Hum). If you get a short to Gnd then the B+ will either blow a fuse or if no fuse then rectifier or HT winding on power Tx will fail.

Regards
M. Gregg

carbondated · 27th April 2011, 08:38 PM

@M Gregg Thanks, that helps!

simon7000 · 27th April 2011, 08:44 PM

If a saturated choke sits around for a long time the magnetic field will diminish. It also drops a bit just about every time you power it up. So if you don't notice any hum, you got an almost free lesson.

Now you can place the same tube back on eBay and honestly say you tried it and did not like it!

sbelyo · 27th April 2011, 08:45 PM

the amp was dead silent before and still dead silent after, so I don't think I shorted any turns

27th April 2011, 03:40 PM	#1
sbelyo diyAudio Member Join Date: May 2004 Location: East Coast	I put a bad ouput tube in my amp, did I hurt it? I did a dumb thing... I got a 6AS7 off of ebay, tested it and it only posted like 10 on a scale of 0-120. I wanted to see if I could hear anything out of it anyway so I put it in my Van Waarde design headphone amp flicked the power switch and plugged in my good headphones like an idiot. I got a load hum out of the left channel and nothing out of the right. I unplugged the headphone and checked the output with a meter just to make sure that I didn't send a stupid amount of DC to the phones, nope just 20 mV I think It was at that time that I noticed some noise coming from the choke in the PSU. One side of it was hot to the touch and the other side was cold. I cut the power and pulled the tube. I put the good tube back in and everything sounds normal but I only listened for 10 minutes so I don't think it had much time to warm up yet. Do you guys think I hurt anything?

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Favorite ouput tube (SE only)	rvrazvan	Tubes / Valves	61	25th July 2011 02:03 PM
About a I/V tube ouput for a Nos TDA1541A dac	gaetan8888	Digital Line Level	1	10th July 2009 07:21 AM
Curious how to put a volume pedal between tube guitar amp head and speakers of same.	nova62400	Instruments and Amps	11	30th May 2006 09:03 PM
is there a good or bad way to put sub on wooden floor	busterno1	Subwoofers	2	6th June 2004 04:45 PM
Not connecting grids/anode can hurt tube?	Redemption	Tubes / Valves	6	14th January 2004 11:20 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

27th April 2011, 07:08 PM	#4
carbondated diyAudio Member Join Date: Jan 2011	Here's something I've always wanted to know - how do you know when a choke is faulty? I hear of chokes becoming 'oversaturated', what happens then?

27th April 2011, 07:18 PM	#5
boywonder diyAudio Member Join Date: Jan 2008 Location: So.Cal.	If none of the tube elements were shorted and it just tested weak, that shouldn't cause any harm.

27th April 2011, 08:38 PM	#8
carbondated diyAudio Member Join Date: Jan 2011	@M Gregg Thanks, that helps!

27th April 2011, 08:44 PM	#9
simon7000 diyAudio Member Join Date: Nov 2008 Location: Oakmont PA	If a saturated choke sits around for a long time the magnetic field will diminish. It also drops a bit just about every time you power it up. So if you don't notice any hum, you got an almost free lesson. Now you can place the same tube back on eBay and honestly say you tried it and did not like it!

27th April 2011, 08:45 PM	#10
sbelyo diyAudio Member Join Date: May 2004 Location: East Coast	the amp was dead silent before and still dead silent after, so I don't think I shorted any turns