Firing up 100w clone...need some help...

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massygt6
Posts: 168
Joined: Thu Feb 16, 2006 12:49 pm

Firing up 100w clone...need some help...

Post by massygt6 »

Hi guys,
I've got a problem with my ceriatone overtone when turning on the standby...I'm blowing fuses in industrial quantity :lol:
The amp is wired and provided with all the "optionals" to run at 100w, so 2 more tube sockets, resistors, wiring....etc etc...
Custom BEEFY power tranny, 350-60-0-350 secondary, 400mA...going into rectifiy section...as ceriatone layout, 6x1N4007 diodes...the FIRST strange thing is that after the rectifiy stage, before the standy switch, I've only 320volts...Don't I should get something around 460volts?
I'm using the wrong rectify layout??
The second strange thing is that after a deep inspection of the amp, I can't find any short, but I'm still blowing HV fuse (500mA FAST)...could be the filter capacitors and the bleed resistors that are not suitable to receive the rectified tension?
I'm using 2x200 uF with 220K bleed resistors...
Any thought, help, advice is greatly appreciated...
thanks...
Max
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Luthierwnc
Posts: 998
Joined: Sat Feb 18, 2006 10:59 am
Location: Asheville, NC

Re: Firing up 100w clone...need some help...

Post by Luthierwnc »

Don't know about your kit but Marshalls usually have a slo-blo fuse in the B+ string. You might need that extra time to let the caps charge.

Skip
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ic-racer
Posts: 1318
Joined: Tue Dec 18, 2007 2:24 pm

Re: Firing up 100w clone...need some help...

Post by ic-racer »

I think the Overtone has two fuses. The standard Slo Blow on the mains and a smaller 0.5A on the secondaries. Its the one on the secondaries that you are blowing, right?

Was it a kit? Who built it you or Niki?
Are your primaries hooked up for the correct line voltage?

Was it built with the standby AFTER or BEFORE those big 220uf capacitors? If the standby is BEFORE the 220s then when you flick the standby switch, these caps fill rapidly and may be blowing the fuse. Niki probably had the fuse set up for the 50W, which has the smaller caps.

The original Dumble had the standby AFTER the first set of capacitors. I'm not shure why Niki changed it on the Overtone.
mlp-mx6
Posts: 1111
Joined: Sat Feb 04, 2006 4:24 pm
Location: NW Atlanta

Re: Firing up 100w clone...need some help...

Post by mlp-mx6 »

Pictures?
Wife: How many amps do you need?
Me: Just one more...
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Structo
Posts: 15446
Joined: Wed Oct 17, 2007 1:01 am
Location: Oregon

Re: Firing up 100w clone...need some help...

Post by Structo »

Also did you happen to use a variac or light bulb current limiter to help form the caps and to check for excessive current draw?
Tom

Don't let that smoke out!
massygt6
Posts: 168
Joined: Thu Feb 16, 2006 12:49 pm

Re: Firing up 100w clone...need some help...

Post by massygt6 »

Everything's OK!!!
needed a SLOW BLOW fuse...
thanks guys!!!
the first note from the guitar was an orgasm :lol:
tele_player
Posts: 311
Joined: Sat Sep 29, 2007 3:27 am

Re: Firing up 100w clone...need some help...

Post by tele_player »

I'm still curious about the rectified voltage. Should be over 450 on the power tube plates.
massygt6
Posts: 168
Joined: Thu Feb 16, 2006 12:49 pm

Re: Firing up 100w clone...need some help...

Post by massygt6 »

oh yeah, sorry, I forgot about that!
I've got 463 volts on the power tubes...tung sol 6l6GC STR, biased ad 35mA...I'm still in the process to track down the preamp voltages, I'll make a post to make a sort of comparison with other amps if its possible...
thanks for the attention...
Max
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