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 Post subject: Fender Blues DeVille 212 re-issue has Static
PostPosted: Mon Mar 25, 2013 2:48 pm 
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I just purchased a Fender Blues DeVille 212 re-issue built in 1993. The speaker reproduces light to moderate static following a 20 minute warm-up with the volume control turned all the way down. Looking at the schematic dated 2004, I note the .1/630 V caps following two 1.5 K resistors going to the grids of V5 and V6. Could one of those components be the source of static. I also read somewhere on the Forum about a similar problem with a Hot Rod, and it was suggested that the two high voltage electrolytics should be replaced. Does this procedure apply to this problem. I did replace the weak Fender 5881 tubes with two RCA 5881. My experience is with antique radios and vintage sound equipment. This is my first endeavor with a guitar amp so I appreciate all input. Thanks!


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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Mon Mar 25, 2013 3:04 pm 
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First of all, you are looking at the wrong schematic. This is the correct one. You have an original USA made Blues Deville. The schematic you have is for the Mexican made Reissue. There are a number of differences between the two,

http://support.fender.com/schematics/gu ... ematic.pdf

The caps you are referring to are coupling caps designed to prevent DC from one amp stage from reaching the next amp stage. Although they could cause a problem, I would first look at the solder joints around all of the tube sockets. The early Blues amps and Hot Rods share similar PCBs and there were problems with poor solder joints causing static over time. You can easily reflow all of the tube socket joints as they are on top of the PCB.

Not sure which high voltage electrolytics you are referring to. In the power supply? Please provide component numbers.

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Mon Mar 25, 2013 3:50 pm 
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I am not sure which ones were being referred to either. I remember the member responding said the two large caps in the power supply which would need to be bled down prior to working on the amp. The two that I see which the member may have meant are c35 and c36. Both are rated 500 volts. I will try reflowing the solder on respective sockets of V5 and V6. Thanks!


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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Mon Mar 25, 2013 4:05 pm 
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The response regarding the possibility of the high voltage electrolytics causing static was with regard to a 2002 Hot Rod and the reason to replace was because the electrolytics at that time were very cheap and prone to cause static. However, that remedy may not apply to my amp as it is an older model. Thoughts? and Thanks!


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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Mon Mar 25, 2013 8:47 pm 
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tubes4me wrote:
I am not sure which ones were being referred to either. I remember the member responding said the two large caps in the power supply which would need to be bled down prior to working on the amp. The two that I see which the member may have meant are c35 and c36. Both are rated 500 volts. I will try reflowing the solder on respective sockets of V5 and V6. Thanks!


ALL of the caps in the high voltage power supply need to be drained before working on an amp or you may get an unpleasant surprise.

You should reflow the solder on all of the tube sockets, not just the power tubes (V4 and V5).

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Mon Mar 25, 2013 8:51 pm 
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tubes4me wrote:
The response regarding the possibility of the high voltage electrolytics causing static was with regard to a 2002 Hot Rod and the reason to replace was because the electrolytics at that time were very cheap and prone to cause static. However, that remedy may not apply to my amp as it is an older model. Thoughts? and Thanks!


Caps are all probably the same between the years.

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Tue Mar 26, 2013 8:08 pm 
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Likely a preamp tube(s), is the source of this "static" sound. You can use a known-good 12AX7 and substitute in each position, V1, V2, V3' one at a time, and see if the noise disappears. :idea:

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Thu Mar 28, 2013 8:56 am 
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shimmilou wrote:
Likely a preamp tube(s), is the source of this "static" sound. You can use a known-good 12AX7 and substitute in each position, V1, V2, V3' one at a time, and see if the noise disappears. :idea:


+1

Another possibility and easier to check first.

Given the age of the amp, I would still check the solder joints.

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Thu Mar 28, 2013 1:09 pm 
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Yes, checking the solder joints is always a good idea. At least they used real solder back then. :lol:

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Thu Mar 28, 2013 1:24 pm 
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shimmilou wrote:
At least they used real solder back then. :lol:


I still do! :lol:

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Fri Mar 29, 2013 8:34 am 
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I have done the following including reflowed the solder around each tube, subbed the 12AX7s with known good tubes, subbed the new RCA 5881s with known good tubes, reflowed solder around joints of DC blocking caps and resistors from V3 plates to grids of V4 and V5 and still the static persists. The static is not objectionable but is still noticeable with volume turned completely down. Occasionally the static is present when the amp is first fired up. Other times the amp doesn't begin to emit static for approximately 20 minutes and then continues at approximately the same low level when amp is run for 3-hour intervals. I am thinking "electrolytics" but want to avoid replacing them at the last resort. Is it possible or advisable to disconnect or isolate the stages before the V3, V4 and V5 stages so as to be certain that the static is in the output stage? Experience with vintage electronics has taught me that static with the volume turned completely down is in the output stage. However, this is my first endeavor with a guitar amp. Sound output is crisp and clear with awesome volume.

I also need some info regarding where to locate a schematic for another "garage sale find". It is a CMI G70 fully solid-state amp with a production date of 10.27.71. I realize this may be the wrong place to post. However, after registering with Gibson Community, for some reason it will not allow me to post a new topic, and I find nothing on the internet regarding diagrams for the G70.

Thanks for all of the suggestions,
Bill


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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Fri Mar 29, 2013 9:01 am 
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Plug your guitar into the "Power Amp In" which bypasses the preamp section and reverb. Maybe the static is from the Plate resistors for the PI (V3), and I doubt that it's the electrolytics, but a possibility still. :idea:

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Fri Mar 29, 2013 11:31 am 
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What shimmilou said.

But ... can you post a sound clip? Is the noise crackly staticy or is it a low frequency oscillation. Slight motorboating caused by a bad PS cap?

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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Fri Mar 29, 2013 2:03 pm 
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It's staticy crackily.

No oscillation, motorboating or hum.


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 Post subject: Re: Fender Blues DeVille 212 re-issue has Static
PostPosted: Fri Mar 29, 2013 2:06 pm 
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tubes4me wrote:
It's staticy crackily.

No oscillation, motorboating or hum.


Good to know. Follow previous advice.

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