New build. Afraid to flick the Standby switch!..Help!

[HDeno]

Hi Guys!!

My Express is finally ready to be fired up... I have been using Ron's bulb limiter with a 60w bulb, and just went thru the inital startup with only the power switch on and no tubes, no speaker... Maybe everything is fine, but before I go off standby I want to be sure.... Here are my concerns:

- First, the trannies have some mechanical hum to them. Not very loud but noticeable, also very faint 'ticking' noise... Is it normal?

- Secondly, my voltages, with and without the bulb limiter:

- Mains (Mesured at the amp power socket)
With limiter: 113 VAC Without limiter: 124 VAC
- Secondaries (Measured where the connect to the diodes on PS board)
With limiter: 565 VAC Without limiter: 619 VAC
-Heaters (Measured on tube sockets)
With limiter: 6.5 VAC Without limiter: 7.0 VAC
- B1 (Measured after the input diodes, or on C15 cap)
With limiter: 395 VDC Without limiter: 422 VDC
- Max negative Bias (Measured on pin 5 on either power tube)
With limiter: -30.5 VDC Without limiter: -35 VDC

So, as you can see, wthout the limiter, those voltages seem quite high to me, apart from the bias, which is OK i think.

Also, with only the power switch on, the bulb is glowing orange.. I do not know if it should be like that or not.. I included a picture without a flash to show the bulb... Again, is it how it should be?...

Thanks a lot guys, I will wait for your feedback before going further in the startup...

Hugues

[soma_hero]

when you put tubes in, those voltages should come down a lot. Unloaded voltages can be very deceiving.

And the bulb should be dimly lit like yours is, at most. If it's fully bright then you know you have a short. I think you're ready to put some tubes in and see um light up!

[gahult]

Hugues,

I would expect that your voltages will be lower when you put tubes in.
No smoke, no sparks, no blown fuse.........all good.
I would be suspect of the ticking noise, could be an ark somewhere.
I would turn it on as you did and if you hear the ticking turn off the lights and see if you can see an ark.
I you don't see any ark I would plug in the tubes and speaker and see what happens.
I have posted a compilation of voltages for 10 other Express builds in the files section you may find helpful.

Gary

[Bruciep07]

what transformers are you using?

[Structo]

I don't think the bulb should be lit at all.

It usually flashes then goes way down as the caps charge.

Double check your PT wiring.

[HDeno]

I don't think the bulb should be lit at all.

It usually flashes then goes way down as the caps charge.

Double check your PT wiring.

I am using Toneslut's trannies....

Hmmm... Now I am a bit confused as some people says that it is normal for the bulb to be lit and you say it shouldnt... I am sure that everything is OK for the PT wiring as it is pretty straght forward and my voltages are close to where they should be...

[Buschman]

Dude , this is the best part. Grab a cold one ,flip the switch, and grin.

[fishy]

I have not used the bulb limiter personally but....
If you are following the Express build guide it states you should see the bulb come on initially while the caps charge and then it should go off.
Unless you have a continuous load on the supply, you will not be using any power.
The high voltages are also due to no load on the supply.

Maybe a few pics of the build will help close the discussion and get you past this.
More than a few of us have been here also.

[HDeno]

Ok guys, I bit the bullet, and went through the rest of the startup!!!!.. IT WORKS!!!... hehe... verry happy right now, but too bad it is late and I can't crank her up!!!

Thanks for the help, I am gonna post build pictures tomorrow!!!

Hugues

[M Fowler]

Hugues,

I'm glad it fired up okay, always nice to hear. Another Express is born. Tomorrow or whenever you can let it cook in for a while and check it over some more.

Mark

[Ron Worley]

Just to clear it up, the bulb will light up rather strongly at first as the PS caps charge when you throw the power switch- but it should degrade to a dull but visible glow from there. When you throw the Standby switch, you may see a little increase in brightness, but not much, then the same dull glow.

Be aware that all B+ readings will be lower than usual due to the limiter.....

[rawnster]

Just to clear it up, the bulb will light up rather strongly at first as the PS caps charge when you throw the power switch- but it should degrade to a dull but visible glow from there. When you throw the Standby switch, you may see a little increase in brightness, but not much, then the same dull glow.

+1

Ron's explanation is how I experienced the bulb limiter with my express build. It would light up initially but would slowly dim down quite a bit, but never completely go out. With 6v6s, the bulb would dim quite a bit quicker than with el34s. When I first tried it with el34s, I thought there was something wrong, for that blasted light stayed bright for a bit before dimming down.

Anyway...........

[Blind Lemon]

+2 = RW