Ceriatone OTS build problems

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wjdunham
Posts: 343
Joined: Thu Jan 22, 2009 6:57 pm

Re: Ceriatone OTS build problems

Post by wjdunham »

Bruciep07 wrote:
Deric wrote:
Check all your voltages cathodes included and post them...
Get the cathode voltages.... V2 and V3 plates are very high. Double check the cathode grounds for both V2 and V3.
The ground side of both cathode resistors/caps are tied together, then tied to the speaker out negative which is tied to the OT negative and effects loop jack negatives, all of which are isolated from ground because of the cliff style jacks. Stupid mistake, I didn't ground any of that :oops:... I'll fix that in the AM, swap out the cathode caps to be safe and report back... Think I could have harmed the OT by lifting the ground? Thanks...
I can't quite see from your layout, but shouldn't these points all be grounded separately (Speaker/OT, FX jacks, Preamp cathodes) to ground lugs mounted so as to keep the amount of wire as short as possible? In most layouts the only one that's wired is that cathode ground, since the jacks usually take care of the other points. I'd mount lugs near the speaker jacks and FX loop jacks, and ground the jacks to those. Seems like a recipe for noise otherwise?
Bill
Bruciep07
Posts: 255
Joined: Sat Feb 07, 2009 6:56 am
Location: Central NJ

Re: Ceriatone OTS build problems

Post by Bruciep07 »

Ok, current voltages are...
V1 Plate, Pin6=173
V1 Cathode,pin8=1.73
V1 Plate,pin1=169
V1 Cathode,pin3=1.80

V2 Plate,pin6=183
V2 Cathode,pin8=1.67
V2 Plate,pin1=175
V2 Cathode,pin3=1.81

V3 Plate,pin6=271
V3 Plate,pin1=271
Cathodes, pins 3,8=56
V3 Grid,pin7=36
V3 Grid,pin2=35

V4 417 Plate, 31mV Cathode
V5 417 Plate, 30mV Cathode
V6 417 Plate, 30mV Cathode
V7 417 Plate, 40mV Cathode
bias -46V

grounded the cathodes as per nik's layout, amp works now! I've got some really bad hum to figure out, and there is a tiny bit of "crackle" on the preamp gain pot, gonna check for leaky caps, move some wires around, and possibly move the cathode ground and separate the loop/speaker Jack grounds, see how that does. Also, FWIW, I plugged my boss GS-10 directly into the loop return and it is noise/hum free...
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Structo
Posts: 15446
Joined: Wed Oct 17, 2007 1:01 am
Location: Oregon

Re: Ceriatone OTS build problems

Post by Structo »

If you ground it just like the #124 layout shows you should be able to get the noise and hum way down. :wink:
Tom

Don't let that smoke out!
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