It is currently Tue Mar 17, 2020 3:12 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 13 posts ] 
Author Message
Post subject: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Mon Jan 30, 2012 4:33 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Jan 30, 2012 4:10 pm
Posts: 3
My hot rod deville 4x10 is having a weird issue with the clean setting. During band practice, I powered on the amp and the clean just sounded muddy and distorted. I put brand new tubes in it, and still the same problem. The lighter/heavy distortion sounds fine, its just the clean that sounds terrible....distorted and muddy. Just seeing if there was something I could do before I take it in and spend lots of money at a repair shop, any ideas?


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Tue Jan 31, 2012 7:01 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Hi jamesjr2790,

Hard to tell what the problem is, simply from your description. It could be tubes, bias, grid resistors, solder joints, or even a relay problem. Are you saying that the channels switch OK? (lights and sound change when switching). Did you change all of the tubes, or which ones were changed? Did you bias the new output tubes?

First, I would make sure that the bias is set correctly with new output tubes if you changed output tubes. I would then check the solder joints and screen grid resistors on the tube socket boards, and solder joints on the main board, and next guess would be that one of the relays in the amp is sticking and might need replaced. Just educated guesses, would need to check the amp with a meter for further evaluation.

The inside of the amp has lethal voltages, even after the power is shut off and amp unplugged. Don't go poking around inside unless you are familiar with the safety precautions when opening an amp. :!:

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Thu Feb 02, 2012 3:19 am
Offline
Hobbyist
Hobbyist

Joined: Mon Jan 30, 2012 4:10 pm
Posts: 3
Thank you for the feed back, now to answer you questions.

I replaced all the tubes, switching between channels works fine also sounds fine, I did not bias the new output tubes because this is my first tube amp and had no idea that thats what I had to do. I know a little bit about electrical work, and have all the tools needed to complete the job.

The amp works fine its just the clean that sounds distorted, Ill take a look at the solders inside and see if i find any discrepancies. How would you go about Biasing the new tubes?

Thanks again for the feedback, I really appreciate it


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Thu Feb 02, 2012 7:19 am
Offline
Hobbyist
Hobbyist

Joined: Sun Oct 30, 2011 8:12 am
Posts: 28
BIASING:
You will notice from these three pages that opinions vary widely on what the correct setting should be. I would advise getting suggestions from others on this board.

http://www.justinholton.com/hotrod/bias.html

http://www.youtube.com/watch?v=19IUadZJf-c

http://www.eurotubes.com/euro-Fender-HRDV.htm


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Thu Feb 02, 2012 11:18 am
Offline
Hobbyist
Hobbyist

Joined: Thu Feb 02, 2012 11:07 am
Posts: 7
Sounds like a bias resistor issue.

The last amp I had in my shop with that issue , it had an open bias resistor

Amps not THAT old is it?...Otherwise I might suggest coupling capacitors.

I have a Hotrod deluxe in the shop right now that someone modded ( like CRAP)
So, I took out the mods and now I find that the Q2 on the "more drive" ckt was fried due to the mod.

_________________
Scott

Audio-Fixation

Vermont


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Thu Feb 02, 2012 12:42 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
JOC, are we talking about a bias resistor in the gain stage, EFX, or phase inverter? Or a dropping resistor to calculate the output tube's idle current? I'm wondering because it sounds like the OP is having trouble with the CLEAN setting, only.


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Fri Feb 03, 2012 8:03 am
Offline
Professional Musician
Professional Musician

Joined: Sun Sep 28, 2008 3:29 pm
Posts: 1162
Location: Lee, MA
If its not the tubes; dollars to donuts its the resistor on the phase inverter, or the screen resistors. They go on all the other Hot Rod series; why should this be any different. I got one where the scumbag who gave it to me put aone screen resistor in, and a jumper for the other. That along with a couple other quick "fixes" allowed the amp to work for aout an hour and a half until it fried. The other 2 HRs I got both had one of those 2 issues happen; one had a leak in the resistor for the phase inverter, the other had burned screen resistors. I replaced the screen resistors with higher valued ones; the amp sounds good & didn't have an issue. The other has a new resistors at the inverter. Apparently there were some QC issues from a vendor on those resistors. Whatever, it works.


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Fri Feb 03, 2012 10:35 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Sat Dec 13, 2008 11:49 am
Posts: 1153
Location: South Bay, CA
Take it to a good Fender amp shop. You can't just replace tubes in your amp -- they need to be biased to sound their best and there is something else going on that an amp tech can diagnose.

If everyone on the site added their location to their profile (hint, hint) you would get more recommendations on qualified Fender techs in your area that we've had luck with.

_________________
Image
'59? Bogen Challenger CHA-33, '65 Bandmaster, '65 Tremolux, 65 Showman;
'74 SF Princeton; '77 SF Princeton Reverb; Dr. Z Mini Z

Our band: http://www.facebook.com/thetoysband


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Fri Feb 03, 2012 10:53 am
Offline
Hobbyist
Hobbyist

Joined: Thu Feb 02, 2012 11:07 am
Posts: 7
I do repairs on ALL guitar amps. I've been in professional electronics my entire adult life and own my own repair shop.
I handle gear from VT, MASS, Conn NH and NY at the moment.
Almost all of the music stores here in the Conn River Valley area are my clients

_________________
Scott

Audio-Fixation

Vermont


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Fri Feb 03, 2012 4:14 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Jan 30, 2012 4:10 pm
Posts: 3
I biased the tubes, and im still having the same problem. I read that it could be a resistor that usually goes out. I think im going to have to just take it in to a repair shop

Thanks everyone for the feedback, I dont really know much about this sort of thing let alone replacing a resistor.


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Fri Feb 03, 2012 4:57 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
One thing you may want to try before carting the thing to a tech: try changing the input/gain stage/EFX/phase inverter tubes. They appear to be all 12AX7's in your amp. You can sub in one new 12AX7 into each position. Or just swap the current 12AX7's around (if you don't have a new one)--- then check for changes to your tone.

Could be you only need a new tube(s).



http://www.blueguitar.org/new/schem/fen ... eville.pdf


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Fri Feb 03, 2012 5:20 pm
Offline
Professional Musician
Professional Musician

Joined: Sun Sep 28, 2008 3:29 pm
Posts: 1162
Location: Lee, MA
Its the resistor for the phase inverter, they're the ones that go & the bad sounding distortion is the result. Its probably not fully gone yet, sometimes they actually break & you can visually see it. Its R57 or 58 on the Deluxe HR, I don't know what it is on the deville; but it will be one of the resistors on the boarrd either right in front or behind the tube socket for the phase inverter. If you know how to keep from getting electricuted; put a multi reader to it; check for continuity & then the volatge. It sucks forking over $85/hour for a resistor... but if you don't know your way around its better than getting shocked (sometimes even when you do, but get lazy).


Top
Profile
Post subject: Re: HELP asap hot rod deville 410 clean is messing up!!!!!
Posted: Fri Feb 03, 2012 5:33 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
There are several resistors around the PI. Perhaps, it's the grid-to-ground resistors? R53 and R54?

I usually just lift one leg of the resistor off the board and measure the resistance. With unit off, unplugged, and PS caps drained. Anything past 10% tolerance (for this resistor) gets replaced. BTW... this grid-to-ground resistor is critical. Even, running hand matched resistors can make a difference. As much as matched-section tubes. IME, of course.

YMMV.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 13 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: