FDP Home Page / FDP Forum / FAQ's

The FDP is made possible by the following companies and individual members like you.
Please use the links below to show them we value their sponsorship.

Apex Tube Matching

Amplified Parts

Yellowjackets Tube Converters

Guitar Center

Jensen Loudspeakers

WD Music

Amazon

Antique Electronics Supply

Sweetwater

Musician's Friend

MOD KITS DIY


* God bless America and our men and women in uniform *

* Illegitimi non carborundum! *

If you benefit and learn from the FDP and enjoy our site, please help support us and become a Contributing Member or make a Donation today! The FDP counts on YOU to help keep the site going with an annual contribution. It's quick and easy with PayPal. Please do it TODAY!

Chris Greene, Host & Founder

LOST YOUR PASSWORD?

......................................................................

   
FDP Jam
Calendar
Find musicians
in your area!
  Search the Forums  

FDP Forum / Amp Mods, Repairs, and Projects / DRRI noisy static

Stratmanx
Contributing Member
**********
*******

Memphis, TN

Jul 4th, 2017 06:18 AM   Edit   Profile   Print Topic   Search Topic

Amp has gotten a staticy light crackling type noise that's been going on for awhile now.

Note: I don't use the reverb channel so V2 is not used.

Quick troubleshooting:

Replaced V1 and V6 (Phase inverter) - no difference.

Changed power tubes - no difference

Removed V1 and powered it up. Still noisy.

Removed V6 and dead quiet

Did not replace tube rectifier yet.

I've ordered all new filter caps, but wondering if screen resistors might be accounting for this

R60 and R61 ?

R62 and R63 ?


Thanks !


(This message was last edited by Stratmanx at 08:39 AM, Jul 4th, 2017)

pdf64

UK

Jul 4th, 2017 07:14 AM   Edit   Profile   Print Topic   Search Topic

How about if the amp is operated without a tube in the V4 socket?
V2, V3, V4 and V5 being specific to the reverb/trem channel.

Stratmanx
Contributing Member
**********
*******

Memphis, TN

Jul 4th, 2017 08:37 AM   Edit   Profile   Print Topic   Search Topic

Give that man a cigar for V4 !

Stock Fender Groove Tubes junk.

I can see by the schematic where that could bleed into the circuit all the time whether you used the Reverb channel or pulled V2.

Not sure how much tone shaping this will give so just putt a JJ in there.

I've got good RCA grayplates but don't think I would need to sacrifice them in this position ?




pdf64

UK

Jul 4th, 2017 09:31 AM   Edit   Profile   Print Topic   Search Topic

The noise MAY be due to a bad plate resistor, so whatever tubes are used could result in the noise.

Really, I suggest not to use anything more than an 'adequate' tube in V4 if you're not using that channel, anything should be fine.
However, V2 and V4 both still need to have reasonably low noise and microphony.

Check if the amp sounds as good with V2,3 and 4 sockets empty; if so, consider leaving it like that, as speaker vibration and operational hours will gradually kill them.

ejm

usa

Jul 5th, 2017 08:26 AM   Edit   Profile   Print Topic   Search Topic

I guess I'm not clear on something.
Did V4 fix the problem?


Stratmanx
Contributing Member
**********
*******

Memphis, TN

Jul 5th, 2017 08:31 AM   Edit   Profile   Print Topic   Search Topic

Yes it did.

It was a wonky Fender Groove Tubes 12ax7.

I decided to yank it after replacing it with a known good tube. No sense in wear and tear on a tube if its not needed.

the plus is a wee bit more gain in the normal channel.

I also pulled V3 and found that also added a tad bit more gain, but found it was just a hair too much, so I put a NOS RCA in there and it seemed to just give the overall tone a bit more clarity.

Probably imagination with the V3 in or out of the circuit, but yeah, the faulty V4 was the one giving me the fits !



FDP Forum / Amp Mods, Repairs, and Projects / DRRI noisy static




Reply to this Topic
Display my email address             Lost your password?
Your Message:
Link Address (URL):
Link Title:




Moderators: Chris Greene  Iron Man  reverendrob  

FDP, LLC Privacy Policy: Your real name, username, and email
are held in confidence and not disclosed to any third parties, sold, or
used for anything other than FDP Forum registration unless you specifically authorize disclosure.

Furtkamp.com 
Internet Application Development

Copyright © 1999-2017 Fender Discussion Page, LLC   All Rights Reserved