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| | |-+  OTS Build Help - Overdrive Squeals		 « previous next »
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Author Topic: OTS Build Help - Overdrive Squeals  (Read 17558 times)
T Wilcox
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« Reply #15 on: August 05, 2012, 05:14:49 AM »
Ok when I think of the dropping string I am thinking of the resistors on the Ps bd where in previous post it was pointed out that there wAs an incorrect resistor. That will screw everything up. I am colorblind so it is impossible for me to confirm. Please tell me this has been corrected.

Todd
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jeffhamula
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« Reply #16 on: August 05, 2012, 05:29:46 AM »
http://www.ceriatone.com/images/completeAmpsPic/CTOvertone/board/left1B.jpg
http://www.ceriatone.com/images/completeAmpsPic/CTOvertone/board/Leftend2B.jpg

I have been still going through the preamp.  My clean is awesome, od sucks bad...

Gratefully from the feedback here I see a problem.  In the pictures (links above) i see a 20k (black resistor) on v1 pin 2 and an unknown resistor where the 2k2 goes next to cap on the end. 

On the layout, it calls for 22k on v1 pin 2 NOT 20k!!!

I  didn't get a 2k2 2w from nik.  I got both 20k (black resistor) and a 22k (light blue).

I initially i put the 20k on v1pin 2 , and the 22k where the 2k2 should be ( since that was my last part). Could this be my od problem?  I now have the 22k on pin 2... My 20k is where the 2k2 is but is wrong I think.

At RadioShack they have only 1/2 watt resistors in stock, no 2 watt... Mouser?Huh?
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hywelg
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« Reply #17 on: August 05, 2012, 10:50:36 AM »
This is where you need to check your values. See resistors highlighted in pink. There is a B+5 which I've not labeled as for these purposes its not relevant, it is the FET supply.

Pins 1 and 6 are the anode (plate) which are connected to the B+ nodes so check the values of your resistors against the layout for your amp.

Pins 2 and 7 are the grids, ignore them for now, you need to get your plate volts right before you go any further.

* DroppingString.png (225.04 KB, 1719x1259 - viewed 678 times.)
« Last Edit: August 05, 2012, 10:53:01 AM by hywelg » Logged
jeffhamula
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« Reply #18 on: August 05, 2012, 04:38:24 PM »
Hywelg - thanks a lot!  I did not think to check niks resistors for whatever reason.  Anyway, i did not receive a 2k2 2watt resistor for B+4. I just ordered and will post results when I get them.
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1993 Fender Blues Deville 2 12
Ceriatone OTS (self built)
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Peavey tmax 210 15 amp
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« Reply #19 on: August 15, 2012, 04:14:38 AM »
Ok guys, I got the B+4 correct by ordering a part off the internet and have the following voltages

Tube   Type   Pin1      Pin3      Pin6     Pin8
                           
V1   NIK       191      1.7         200      1.6
   Jeff           177.     1.7          245.    1.1
V2   NIK        200      1.7         201      1.7
   Jeff           180.      1.9.      265     1.1

V3   NIK       298      56         289      56
       Jeff       288.     56          276   56

What can I do next?  Overdrive sorta starting to work but sounds like a bass synth pedal phaser...
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1992 American Fender Strat
Edwards jimmy page les Paul
1993 Fender Blues Deville 2 12
Ceriatone OTS (self built)
G12 65s in Marshall cab
1999 Fender Jazz Bass
Peavey tmax 210 15 amp
Pearl Export Drums
hywelg
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« Reply #20 on: August 15, 2012, 06:55:13 PM »
Something is still amiss with your voltages. V1b and V2b (both pin 6's) are both now 20%+ on the high side.

What is the voltage at the OT Centre tap?.

Next step is to download all the pics from the website and start redressing your leads to look identical, that is routing, and length. Very important this, you might need to unsolder some and shorten some others. Google 'Dumble Lead Dress ' and you'll find loads. It seems to me that what you have is oscillation in the od circuit. So give special attention to V2.
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« Reply #21 on: October 18, 2012, 12:25:49 AM »
Hey guys, I just wanted to follow up.  I took the amp to a local tube amp guru (Utah), and he went through the entire amp and checked my work.  It turns out my main problem was I left the ground off the bar and had a few cold solder joints.

The repair was very reasonably priced and my amp now rips!!!!  I am so excited.  I could not be happier.  I have not gigged the amp yet but had rehearsal last week and it really cut.

Thank you to the many people that helped me from this forum.  The tech said don't be afraid to use a really hot iron.  I personally turned my iron down because I overheated my deville pcb board when I recapped it. 

Thanks again !!!!!! U rock!
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1992 American Fender Strat
Edwards jimmy page les Paul
1993 Fender Blues Deville 2 12
Ceriatone OTS (self built)
G12 65s in Marshall cab
1999 Fender Jazz Bass
Peavey tmax 210 15 amp
Pearl Export Drums
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