220v version Paramount

Demsy · 2233

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Offline Demsy

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on: September 01, 2012, 07:14:17 PM
I have just bought the 240v version of the Paramount. Our line voltage here in Indonesia is 220v, I use a 5kva automatic stabilizer for the audio system. I can say that the voltage is pretty stable at 220v all the time.
My question, as the Paramount is supplied with a 240v transformator, what do I need to anticipate this, other values of resistor for instance? The kit has just started it's long journey to Jakarta yesterday, so I have like two to three weeks to gather the parts needed to anticipate this matter. But as I have nothing at the moment, yet, no diagram etc, maybe people that has built it could help me? Here in Indonesia we sometimes have to order certain parts from abroad, so it takes time before the parts needed are at hand.
Thanks in advance,
Demsy



Offline John Roman

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Reply #1 on: September 02, 2012, 03:49:30 AM
I would suggest a step up transformer to bring line voltage closer to 240VAC.
John

Regards,
John
Extended Foreplay 3 / 300B Paramount's / BassZilla open baffle/ Music Streamer 2 / Lenovo Y560-Win7-JRMC & JPlay


Offline Paul Joppa

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Reply #2 on: September 02, 2012, 06:35:44 AM
You are probably OK without any changes. The only thing I'd check on is the filament voltage.

When I tested the prototype (I just looked up my notes) I found 5.29 volts DC at 120v/240v. So, proportionally, I'd expect 4.85 volts which is only 3% low - well with even the 5% recommendation, and certainly within the 10% maximum tolerance. A low filament voltage does not becom important until the tube is well worn, so there is plenty of time to make changes if there are any problems. I don't remember what wire is used, but using a larger wire diameter (e.g. 16 gauge) will give the maximum voltage to the actual tube terminals.

If the actual voltage in use is too low for comfort, there are Schottky diodes with a smaller voltage drop than the ones in the kit; a simple change will raise the voltage. But as I said, you have plenty of time - a couple years at least - before you would need to do anything.

Paul Joppa


Offline Demsy

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Reply #3 on: September 03, 2012, 02:24:03 AM
Thanks for your reply, Paul. I guess I'll have to wait until the amplifiers are finished. I do recall while buiding the Hagermann's Cornet phono pre, playing with the filament voltage did change the sound. So I might try to get the plate voltage right from the beginning and for that I might ask your suggestion once I've finished building it.

@John, thanks for your suggestion, but I'll stick with Paul's suggestion first.