Blinking power light switch on T7 preamp

ricmon · « **on:** 22 Jul 2009, 08:11 pm »

Frank the power switch on my T7 preamp is flickering. The funny part is it flickering to the music not randomly. Also it exhibits the same behavior when the volume is up or down (no sound from the speakers).

thanks
Ric

Wayner · « **Reply #1 on:** 22 Jul 2009, 09:06 pm »

There is a 120 volt neon lamp in the switch. Your particular one seems to be a bit sensitive to vibration. One thing to do is to try isolate your T7 as it is obviously seeing lots of vibration and that may not be the best for the tubes either. The flickering lamp will not effect the sound at all.

Wayner

charmerci · « **Reply #2 on:** 23 Jul 2009, 12:22 am »

Maybe I can send you my power strip with its flickering power switch light so you can have a matching pair.....

(Still flickering after all these months, Wayner.)

srb · « **Reply #3 on:** 23 Jul 2009, 12:44 am »

Never ever had a neon lamp, whether in a piece of eqipment or a power strip or a night light, that didn't go wonky. Neon = Bad. LED = Good.

Steve

Wayner · « **Reply #4 on:** 23 Jul 2009, 01:11 am »

Unfortunately, any power switch that handles 120 volt, will not offer an LED light source. That would have to be offered by a less then 9 volt power supply. The purpose of the AVA power switch is to let the user know that there is power from 120 vac to the unit.

Wayner

srb · « **Reply #5 on:** 23 Jul 2009, 01:47 am »

That is true. However, I prefer to switch AC with a relay.

Steve

ArthurDent · « **Reply #6 on:** 23 Jul 2009, 02:00 am »

Been there on my old Hafler, and the Omega upgrade. Frank was kind enough to replace the switch when it went in for the Insight upgrade.

Wayner, side question if I may - you note < 9 volt for LEDs, which brings two questions to mind. How do they make the LED Christmas lites, there's no transformer on them ? Also, as some cars & most trucks are going to them for signal & brake lights, does the 12 vdc make a difference ? Just curious

srb · « **Reply #7 on:** 23 Jul 2009, 02:51 am »

The LED Christmas bulbs actually have a miniature AC/DC rectifier built into the bulb.

LEDs have different voltage requirements depending on the design, but a majority of them operate in the 9V-15VDC range. Others can operate on lower voltages of 1.5V-3VDC, like the ones in one and two cell LED flashlights.

Because we are seeing more LEDs with rectification and voltage adjustment circuitry built-in, I think we'll start seeing AC switches with LED indicators appearing in the near future.

Steve

tekwiz · « **Reply #8 on:** 23 Jul 2009, 04:13 am »

Wayner · « **Reply #9 on:** 23 Jul 2009, 11:27 am »

Christmas tree LEDs are also in series. Yes,, you can use higher voltages to run LEDs, but the resistor starts getting pretty large and defeats the whole purpose of "energy saving" as you get further away from the usual 2.2 volt DC requirements of the normal LED.

The switch Frank uses is of very high quality and the lamp is rated for something like 100,000 hours, which would be about 12 years of continuous "on" use.

Or give Frank a call and I'm sure he could make arrangements for the switch to be replaced.

Wayner

gjs_cds · « **Reply #10 on:** 23 Jul 2009, 01:34 pm »

I'm not a big fan of the LED lights anyway--they're just too damn bright for my tastes. My home theater's power supply has a few of them, we always throw a pillow in front of it because it's just too distracting & annoying. I also made the mistake of installing some LED switches in my car, which are about to be covered by electrical tape.

avahifi · « **Reply #11 on:** 23 Jul 2009, 01:39 pm »

The flicker is likely caused by the internal neon lamp slowly running low on neon, which eventually leaks out through the glass. Or, it could be caused by low AC line voltage. Either will cause the voltage applied to not ionize the gas fully and cause the flicker. Most lamps last for years and years, but sometime one gives out in a few years. No way to know that in advance.

The cure is to replace the switch. We have spares in stock for most units. For the past several years we have connected them with solderless "push-on" connectors so do it yourself replacements are pretty easy. If the equipment is three years old or less, we will send you one free. Or you can send it back for the fix if you are not a great do it yourselfer.

Call us for details and help. 651-330-9871

Regards,

Frank Van Alstine

ricmon · « **Reply #12 on:** 23 Jul 2009, 07:50 pm »

Quote from: Wayner on 22 Jul 2009, 09:06 pm

There is a 120 volt neon lamp in the switch. Your particular one seems to be a bit sensitive to vibration. One thing to do is to try isolate your T7 as it is obviously seeing lots of vibration and that may not be the best for the tubes either. The flickering lamp will not effect the sound at all.

Wayner

Wayner the T7 is pretty well isolated. As I stated the light flickers with the volume all the way down (no sound from speakers to stimulate chassis).

Frank I'll be in touch about a replacement switch.

Thanks Ric

ArthurDent · « **Reply #13 on:** 23 Jul 2009, 10:48 pm »

Quote from: srb on 23 Jul 2009, 02:51 am

The LED Christmas bulbs actually have a miniature AC/DC rectifier built into the bulb.

LEDs have different voltage requirements depending on the design, but a majority of them operate in the 9V-15VDC range. Others can operate on lower voltages of 1.5V-3VDC, like the ones in one and two cell LED flashlights.

Thanks Steve

Quote from: Wayner on 23 Jul 2009, 11:27 am

The switch Frank uses is of very high quality and the lamp is rated for something like 100,000 hours, which would be about 12 years of continuous "on" use.

Thanks Wayner, if I had to guess I'd say I got 15 years of solid light, and another 15 of flickering, before it finally went dead. On that basis the one Frank put in will outlast me, of course the amp will anyway.

JD

tekwiz · « **Reply #14 on:** 25 Jul 2009, 05:19 am »

avahifi · « **Reply #15 on:** 25 Jul 2009, 02:36 pm »

Of course since the neon lamp is built into the power switch, it is not cost effective to replace it independently. You would need extra wiring from the low voltage DC power supply and the appropriate dropping resistor and the ability to take apart and put back together the switch.

Or just very neatly drill extra holes in the internal and external front panels and install the LED independently. A whole lot of extra cost and bother it seems to me.

Regards,

Frank Van Alstine

rcag_ils · « **Reply #16 on:** 25 Jul 2009, 02:48 pm »

The neon lamp in my 1959 KLH model 8 table radio doesn't flicker after all these years.......

Why bother with all the extra work for LED unless it's designed for it, just replace the darn switch.

Wayner · « **Reply #17 on:** 25 Jul 2009, 06:48 pm »

We have Bingo! No offense, but fixing a power switch reminds me of my dad spending 3 dollars to fix a .99 cent entension cord.

Wayner

TomW16 · « **Reply #18 on:** 25 Jul 2009, 07:36 pm »

Quote from: Wayner on 25 Jul 2009, 06:48 pm

We have Bingo! No offense, but fixing a power switch reminds me of my dad spending 3 dollars to fix a .99 cent entension cord.

Wayner

Yep, I puchased an extension cord, cut off the end and wired it up to my table saw since it was cheaper than buying the parts separately. Crazy!

tekwiz · « **Reply #19 on:** 25 Jul 2009, 11:10 pm »