Bottlehead Forum

Bottlehead Kits => S.E.X. Kit => Topic started by: Zimmer64 on January 01, 2014, 01:01:31 AM

Title: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: Zimmer64 on January 01, 2014, 01:01:31 AM

Hi there,

I am assembling my kit and am missing the 0.1 ohm 5w resistor that is used in den DC heater supply. What does this resistor do? Can I use a jumper wire until I have bought a replacement? All shops are closed in Switzerland until the 3rd.....

Thanks for your advice and happy New Year!

Michael

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: mcandmar on January 02, 2014, 05:18:37 AM

I assume you know if you contact [email protected] or phone Eileen they will send you a replacement.  If you want one quickly and cant source them locally then PM your address and i'll send you one as i have a few Dale .1ohm resistors here. Post from Ireland -> Switzerland should only take a day or two.

I'm not really sure as to its purpose but i think its more to limit startup current rather then smoothing the supply so i don't think it would be a good idea to bypass it with a jumper.

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: Zimmer64 on January 02, 2014, 05:43:22 AM

Thank you for the kind offer. I will try to get this resistor locally tomorrow. Finished the build this morning. Installed impedance switch and C4S. Resistance checks all ok. Just can't fire it up just yet  :'(

Cheers

Michael

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: howardnair on January 02, 2014, 12:22:15 PM

what zimmer was asking was of course can he use a jumper--why a jumper-- well!!!  a jumper could have .1ohm resistance--zimmer measure a jumper and see

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: Paul Joppa on January 02, 2014, 01:52:52 PM

The added resistance adjusts the DC voltage to the heaters. (It has other benefits, not easy to summarize in a line or two.) The adjustment is small less than a half volt, so it won't damage the tubes to use a jumper for a few hundred hours. But don't leave it out for too long.

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: Zimmer64 on January 02, 2014, 08:14:56 PM

Thank you all. I can source this resistor locally.

Michael

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: Zimmer64 on January 04, 2014, 02:45:01 AM

Got one today, put it in and fired it up. No smoke, no hum, no hiss, just great music!

Michael

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: Grainger49 on January 04, 2014, 05:27:12 AM

Michael,

I love to hear those stories.  Too often we only see problems on the board.  I believe the vast majority fire up first time and work as intended.

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: Zimmer64 on January 04, 2014, 05:36:10 AM

Yeah. I just took it slowly. Read a step in manual, attached the parts as instructed, checked against the photos in the manual and only then soldered if so instructed. After each section I took high resolution photos and checked the solder joints on my iPad (magnified). That process really minimizes the chance of errors, plus gives you a nice documentation of your work.

Michael

Title: Re: Help required: Missing 0.1 ohm resistor. Can I use jumper cable?
Post by: Grainger49 on January 04, 2014, 08:58:48 AM

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi244.photobucket.com%2Falbums%2Fgg7%2FGrainger49%2FSmiles%2Fthumbsup_zps4d4312f2.gif&hash=fcc4a0e009432b061e176ccb2802f87dcbbe185c)

Slow and meticulous beats fast and sloppy any day.  I wouldn't expect you to be sloppy either.

But so many first kit builders are in a hurry and have no idea how to make a good, solid solder joint.