Smash, no sound from the right

[antoineestephan]

Hi, just finished building my smash preamp.
The resistance check went good, I got 470k on terminals 3 and 10, where I should get 475k, no problem I assume.
Then proceeded with voltage check, it went mostly well
On terminals 4,9 and B5 I got 145 instead of 150
On terminals 15,16 I got 54V, and on 21,22 I got 49V, on A2, C2 I got 46V, and on A3,C3 I got 49V, all instead of 55V but still in acceptable values.
On terminals A4, C4 I got 1.62V, and on A8,C8 I got 1.60V instead of 1.57V, am I ok here ?
On terminals 17, 29, B7 I got 171.8V instead of 200~220V, and on terminal 35 I got 178.8V instead of 215~235V, which are low.
I live in Lebanon where electricity is 220V nominally, but in practice we get in the 200~210V region sometimes even less.
I connected the preamp to my power amp, and turned everything on, after some humming and noises, I got music only from the left side, checked my connections and switched cables, nothing from right, so, need help, any suggestions, ideas would be welcome.
Good day to all

 

[antoineestephan]

Hi
After posting my question, I tried to play around a little bit with my smash, it seems that working it was beneficial, after about half an hour of listening, I started to hear low sound from the right, which kept on increasing, now that I have about 5 hours into it, I'm having sound on both channels on 2 inputs, the innermost is still left only, even though the right is still weaker I think.
But God that hum.
I have a vintage Sony power amp that has an attenuator, so I tried decreasing the level on the Sony while increasing it on the smash, that made the situation better but didn't rid me of the hum.
So now my biggest problem is the hum and the state of the voltage differences in my initial post, if those are a problem I'm not sure.
And one more question my input selector points to the wrong direction, I mean when it's pointing to the right my left input is selected and vice versa.
Now I'm letting it cool down a bit, later I will try switching the tubes to see if that has any influence. And report.
Good day

 

[Paul Birkeland]

What's your wall voltage?

-PB

 

[antoineestephan]

220V nominal, but usually it's 200~210V sometimes even less.

 

[Paul Birkeland]

but in practice we get in the 200~210V region sometimes even less.

I didn't notice this before.  If your voltage is this low, the preamp simply will not work properly.

You can get a small isolation transformer with a bit of a step-up.  Usually you see something like 220V:240V, and that is going to be mandatory to get satisfactory results out of the Smash.

(I would not, however, that with 175V of B+, the Smash-up might actually take care of the noise problem, but I'd start with obtaining proper line voltage)

-PB

 

[antoineestephan]

Thanks for the quick response, I actually noticed that this evening when the voltage drops the most, the problem worsened, at one point the OD3 was barely glowing. It was then that I got a sort of whaling sound and turned off my system.
I actually got the smash up with the smash, but I was thinking of running it stock for about a month before upgrading.
I actually haven't heard of step up transformers from 220 to 240V, but wouldn't that add noise to the system?
We have voltage stabilizers that could provide constant 220V, would that be good enough?
And what kind of watts are we talking about? How potent should it be?

 

[Paul Birkeland]

I actually haven't heard of step up transformers from 220 to 240V, but wouldn't that add noise to the system?
We have voltage stabilizers that could provide constant 220V, would that be good enough?

The transformer shouldn't add noise, but a stabilizer that provides constant 220V would be perfect.

And what kind of watts are we talking about? How potent should it be?

This depends a little bit on what else you might want to run with it.  50VA would be fine for the Smash, while a bit more capacity might handle future electronics.

-PB

 

[antoineestephan]

Hi
Thanks PB I had an old stabilizer layin around all I had to do was look for it. And that's it now all my voltages are within specs, even the noise is a lot less than it was.
I'm  listening to my smash preamp now and it's a satisfying experience.
Now I'll be starting the smash up upgrade very soon.
Thanks for your help and patience.
Regards
Antoine Estephan

 

[Paul Birkeland]

I'm glad you were able to sort this out without too much time and money invested. 

Our overseas transformers really like to be run between 230V and 240V, though our newest transformer for the Stereomour and Seductor amplifiers, which can give proper operation clear down to 210V or so.

-PB

 

[antoineestephan]

Thanks PB for the assistance, now I have another topic and another problem with my smash up, please oblige
Regards