WiredState Audio Community

by KD » Thu Dec 11, 2003 9:58 am

vintage_dog wrote:we plan to swap your unit with a new one altogether...pls text me at 0917 621 5056 for details.

Acknowledging receipt of replacement unit this morning from toobs. Thank you.

by **Gabriel** » Thu Dec 11, 2003 6:58 pm

I got the replacement tubes today. Brushes with the volume knob or taps on the chassis are no longer audible through earphones. Both channels also exhibit low hum levels at zero volume. I can only guess that this would not be audible using loudspeakers since I recently sold my only pair and the ordered replacements have not arrived.

One tube in the new pair causes a slightly louder hum at zero volume but well below that of the damaged tube. I tried pairing the good tube from the previous pair with the quiter one from the new pair and both sound more similar in above aspect. I can do this right? Since all four are supposed to be of the same type?

by **vintage_dog** » Thu Dec 11, 2003 7:15 pm

Gabriel wrote:I got the replacement tubes today. Brushes with the volume knob or taps on the chassis are no longer audible through earphones. Both channels also exhibit low hum levels at zero volume. I can only guess that this would not be audible using loudspeakers since I recently sold my only pair and the ordered replacements have not arrived.

One tube in the new pair causes a slightly louder hum at zero volume but well below that of the damaged tube. I tried pairing the good tube from the previous pair with the quiter one from the new pair and both sound more similar in above aspect. I can do this right? Since all four are supposed to be of the same type?

yes of course...i wouldnt be too concerend about slight hum so long as you dont hear it from your normal listening position....low level hum IS normal for most tube gear...the important thing is that is it distracting you away from the music?

also, check your connections as well...hum is caused by poor interconnects and also poor grounding of your gear. also, those tubes were tested as okay, so it may also be the synergy with your other components.

if you continue to be bothered by the hum, suggest you send over the preamp and tubes and we will refund you in full the amount including cost of shipment...

by **Gabriel** » Thu Dec 11, 2003 7:36 pm

No sir. The hum levels now do not bother me. The damaged tube's hum was distracting only with headphones or with loudspeakers playing tracks like Jacintha's Moon River where the dead quiet background gave it away.

Thanks again for a great product.

by KD » Fri Dec 12, 2003 11:52 am

KD wrote:Acknowledging receipt of replacement unit this morning from toobs. Thank you.

Confirming: replacement unit functions normally without defects detected in original unit. Thank you.

by **arnel90** » Mon Dec 22, 2003 10:23 pm

i moved my audio set up to another room and when i powered it up there was a distorted hum coming out of the speakers, like it was grounded or something?....i didn't use the preamp for about an hour then connected it again and the humming was gone....pls. explain what just happened, thanks.

by **vintage_dog** » Mon Dec 22, 2003 10:32 pm

arnel90 wrote:i moved my audio set up to another room and when i powered it up there was a distorted hum coming out of the speakers, like it was grounded or something?....i didn't use the preamp for about an hour then connected it again and the humming was gone....pls. explain what just happened, thanks.

could be loose interconnects...when interconnects are not properly set (or grounded), sometimes you get hum...

another source of hum is loose connection of tubes in the sockets...

by **arnel90** » Tue Dec 23, 2003 7:52 am

thanks sir V_D

by **toobs** » Tue Dec 23, 2003 11:53 am

Hi Arnel90,

Yes, as what vintage dog mentioned, the hum you encountered could be loose connection of the tube in its socket. If you are comfortable removing the 12AU7 tube, you can do the following;

a. After removing the 12AU7, use an old toothbrush and carefully brush the tube pins with soap (Axion or Joy) and water.

b. Wash thoroughly in running water.

c. Dry it with paper towel

d. Plug back in the tubes taking note the orientation of the pins.

If the hum still persist, there could be other sources of the problem. I suggest then that you call/text me at 0917-897-0798 so we can fix the problem or provide you a replacement unit.

toobs

by **HotonE** » Tue Dec 23, 2003 12:50 pm

Excuse the ignorance, but did you say wash with running water? I know (read a long time ago that washing CDs is safe other than using any type of cleaner), but this is also okay for tubes? All types?

by **arnel90** » Tue Dec 23, 2003 1:30 pm

thanks toobs, great tips!....so far its doin great now, i just made sure my connections were secure again.

by **toobs** » Tue Dec 23, 2003 6:12 pm

Hi HotonE,

Washing the 9 pin peanut tubes in running water is safe. Just be sure that it is dry before plugging it back in your preamp. It is just not normally done by some users since they want to preserve the labels on the tubes.

As for other tubes like 4 pins, octals which uses a base, washing is also safe but we usually wash it upside down with the pins pointing upwards. This is to avoid water seeping inside the base which takes longer to dry.

toobs

by **Gabriel** » Fri Jan 16, 2004 3:45 pm

I have noticed a couple of things with the preamp in my setup that I would like to clarify;

1.) Speakers emit a popping sound whenever I turn on my amp. The same popping sound is given off whenever I turn on my electric fan.

2.) Speaker drivers move a lot even with no sound coming from them when voltage fluctuations occur. I posed this question at pinoydvd and a reply made mention of subsonic frequencies.

These only occur if I connect the preamp to the main-in of my NAD integrated.

Are these to be expected or are they causes for alarm?

by **vintage_dog** » Fri Jan 16, 2004 5:18 pm

Gabriel wrote:These only occur if I connect the preamp to the main-in of my NAD integrated.

? net, remove the preamp from the NAD mains!

by **Gabriel** » Fri Jan 16, 2004 6:30 pm

vintage_dog wrote:
Gabriel wrote:These only occur if I connect the preamp to the main-in of my NAD integrated.

? net, remove the preamp from the NAD mains!

Sir you may have misunderstood. My amp does not have an AC outlet. What I did was use the preamp and the power section of the NAD amp. The power section sockets are labelled Main-in. Both are plugged into a powerstrip and then a Yaden AVR.

by **vintage_dog** » Fri Jan 16, 2004 6:45 pm

okay, try to turn on the amp only after the preamp is turned on; also, in turning off, start with the amp first.

also, try connect the preamp directly to the AC mains and not on the AVR...

if symptoms persist, change the NAD...hehehe

by **Gabriel** » Fri Jan 16, 2004 7:41 pm

vintage_dog wrote:okay, try to turn on the amp only after the preamp is turned on; also, in turning off, start with the amp first.

also, try connect the preamp directly to the AC mains and not on the AVR...

if symptoms persist, change the NAD...hehehe

This is the sequence I follow when I power on my system and when I turn it off.

About plugging in the preamp directly into the mains, would this be advisable if these fluctuations continue over an extended period?

by **vintage_dog** » Fri Jan 16, 2004 10:51 pm

you should be okay so long as AC voltages don't go way beyond 235v...that's pretty "normal"...

by the way, i just remembered, my old NAD integrated amp makes that thumping noise eveytime it's switched off or on...

by **arnel90** » Sat Jan 17, 2004 2:00 am

just noticed it now, even when the volume control of the preamp is fully closed i can still hear music coming from the left speaker, the right speaker has the normal low hum. i tried interchanging the tubes but the left speaker still emits music.

by **Gabriel** » Sat Jan 17, 2004 7:07 am

vintage_dog wrote:you should be okay so long as AC voltages don't go way beyond 235v...that's pretty "normal"...

by the way, i just remembered, my old NAD integrated amp makes that thumping noise eveytime it's switched off or on...

Sir I think those thumping noises are due to the preamp since they are not present if I use my integrated amp alone.

WiredState Audio Community

SUPPORT: Tono Audio products

Who is online