240V stereomour

[srhombeus]

Hi All,
I'm a new member from Turkey.My stereomour kit is shipped yesterday.And I have a few questions to ask you..  How will be voltage measurements for 240V transformator? I think it will be different from the manual results..   And also I am planning to build the kit as 4 ohm,I will use it with my visaton B200s. They are at 6 ohms.

I think ı would have more questions when ı'll receive the kit. 
Ä°t's great to be a member of bottlehead community.

[Grainger49]

The voltage measurements are not taken on the incoming line side of the transformer.  So the output voltages and the rectified voltages will all be the same as in the US.  There was one Bottlehead who had a 220V incoming rather 240 and the output voltages ran a little low.

As always, with an odd impedance, try each secondary tap and see which sounds the best to you.

[srhombeus]

Thanks for your answer sir.Our country has also 220V. It looks there will be some change in the measurements..

[fullheadofnothing]

The problems people are having with 220V is on the Paramount. The Stereomour uses a different power transformer and is a completely different design. There was one person on the forum who was concerned about having issues with their Stereomour before it even arrived (sound familiar...?). He never posted a followup about whether or not he had any issues with the built amplifier.

As for impedance selection, 6Ω is a nominal figure- all speakers have varying impedance over different frequencies. It's fine to have a higher impedance speaker on a low tap, but lower impedance being driven by high is something you always want to avoid. Looking at the graph, your speakers are below 8Ω from 70Hz to 4KHz. 4Ω is the much better choice in this instance; set it and forget it.

[srhombeus]

Thanks for your informations,I just wanted to get some information about measurements before i start to assembly.I don't think there will be any problem with the kit,because there are also a few guys who are using stereomour in my country with 220V..

 

The problems people are having with 220V is on the Paramount. The Stereomour uses a different power transformer and is a completely different design. There was one person on the forum who was concerned about having issues with their Stereomour before it even arrived (sound familiar...?). He never posted a followup about whether or not he had any issues with the built amplifier.

As for impedance selection, 6Ω is a nominal figure- all speakers have varying impedance over different frequencies. It's fine to have a higher impedance speaker on a low tap, but lower impedance being driven by high is something you always want to avoid. Looking at the graph, your speakers are below 8Ω from 70Hz to 4KHz. 4Ω is the much better choice in this instance; set it and forget it.

[srhombeus]

Hi again.I finally received the kit today.Thanks for great packing.I started to assembly very fast.But unfortunately,while soldering the pcb,i made a mistake with the 300k ohm 3 watt resistor.While desoldering I brake one lead of the resistor and It's impossible to solder it now..  Is it possible if i can substitute it with an other resistor in my country? I am waiting for your advices.Thank you very much.

[Grainger49]

Sounds like you are not near any store that might have a replacement part.

Would it be possible to solder a piece of wire to the resistor where the lead broke off?  Is there any part of the lead left there?

[srhombeus]

No unfortunately,there's no lead left on the resistor..
I will look at the stores but i don't think that i will find the same part with same specs.  I completed 2 boards today but unfortunately just this part is missing.

Sounds like you are not near any store that might have a replacement part.

Would it be possible to solder a piece of wire to the resistor where the lead broke off?  Is there any part of the lead left there?

[Paul Birkeland]

Luckily, the 300K/3W part isn't an incredibly sensitive value.

You can probably find a 270K resistor easily enough, and a 2W or 3W part will work well.  (We don't recommend a 1W resistor here, it will get hot enough to char your driver PC board)

You could also go a little over 300K, a 330K 2W resistor would also be OK.

Let us know if we can be of any additional assistance.

-PB

[srhombeus]

Thanks for your help.Tomorrow i will look at the stores for these specs.I would also like to ask you if the side of the resistor is important while assembling ? Does it have negative,positive side ?

[Paul Birkeland]

Nope, resistors can go in any way you like.

-PB

[srhombeus]

Hi,I just found 301k 2 watt metal film and 330k 2 watt carbon resistor from the stores. Which one do you suggest that i use ?  301k 2 watt is really smaller than the one you send with the kit..

[Grainger49]

Since both are 2W I would use the 301k since it is essentially the design value.

[srhombeus]

Thanks for your answer.I checked the ohms with the voltmeter.No problem with the ohm,but how can I check the wattage of the resistor ? I am not sure if the seller had mistake,because this resistor is nearly the half of the old one..I don't want the blow the pcb because of this cheap part.

[Grainger49]

Sometimes the power rating is written on the resistor sometimes it is not.  I don't know another way to verify its power rating.