It is currently Mon Mar 16, 2020 10:08 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 35 posts ]  Go to page 1, 2, 3  Next
Go to page 1, 2, 3  Next
Author Message
Post subject: Hot Rod Deluxe LOUD hum
Posted: Thu Mar 06, 2014 2:56 pm
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 06, 2014 2:48 pm
Posts: 12
I recently completed the Fromel mod on my HRD. When I turned it back on, there was an incredibly loud hum. I switched out the preamp tubes. The hum went away but V1 sounds slightly microphonic. I switched V1 out with a brand new tube and the hum came back. I put the microphonic tube back in and the hum goes away. Does anyone have any ideas?

Thanks in advance.


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Thu Mar 06, 2014 4:44 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
V1 is often microphonic , normal if not too microhonic . The first tube is very sensitive .


Last edited by stratele52 on Thu Mar 06, 2014 4:48 pm, edited 2 times in total.

Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Thu Mar 06, 2014 4:46 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
The amp modder's creed (same as that of a surgeon):

"FIRST......DO NO HARM."

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Fri Mar 07, 2014 2:52 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
Retroverbial wrote:
The amp modder's creed (same as that of a surgeon):

"FIRST......DO NO HARM."

Arjay



+1


mattmconnell,

HRD is a amp not easy to work on and to modify unless you are a expert .

Moving some wires could induce lots of noise or hum . I always take some photos before I work on these amps to keep wire like there where before.


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Fri Mar 07, 2014 1:55 pm
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 06, 2014 2:48 pm
Posts: 12
I was looking over everything I did. I had replaced the volume pot without re-using the bracket that is mounted to the PCB leaving R63 open. Could this possibly be what is causing all the racket? A grounding issue?


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Fri Mar 07, 2014 2:00 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
mattmcconnell wrote:
I was looking over everything I did. I had replaced the volume pot without re-using the bracket that is mounted to the PCB leaving R63 open. Could this possibly be what is causing all the racket? A grounding issue?



Leaving R63 open ! If you live this resistor there with one side not connected , it act like an antenna = hum , noise....


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Fri Mar 07, 2014 4:40 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
The volume pot was already an audio taper pot, why replace it? You can solder R63 to the back of the new pot, or simply put the original pot back in and put R63 back where it was.

I hope that you didn't change the 5 watt resistors to 330 ohms. :!: This is a big mistake on Fromel's part, he doesn't quite know what he's doing by recommending the resistor change.

_________________
---> "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: Hot Rod Deluxe LOUD hum
Posted: Fri Mar 07, 2014 5:11 pm
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 06, 2014 2:48 pm
Posts: 12
Don't know how I fixed it but I did. That scares me. The volume pot is a much more gradual increase in volume now, much smoother than before.

The 5watt resistors are 470 ohm.


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Fri Mar 07, 2014 10:58 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
mattmcconnell wrote:
I was looking over everything I did. I had replaced the volume pot without re-using the bracket that is mounted to the PCB leaving R63 open. Could this possibly be what is causing all the racket? A grounding issue?


That's interesting.

R63 is located next to the clean volume pot, which as shimmilou pointed out, is already an audio taper pot. However, the Fromel mod volume pot replacement is for the MASTER volume control:

"Lead Master Volume - Ever wonder why this amp gets extremely loud after you turn it up past 2. Fender uses a linear taper pot for the Master Volume when it should be an audio taper. This mod gives you usable control of the drive channel so you can get good tone without playing at stadium volume."

http://fromelelectronics.com/modificati ... Rod-Deluxe

Looks to me like you replaced the wrong pot, otherwise, I have no idea how you messed up R63.

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

_________________
Bill

Image


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Fri Mar 07, 2014 11:00 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
mattmcconnell wrote:
Don't know how I fixed it but I did. That scares me. The volume pot is a much more gradual increase in volume now, much smoother than before.


Yes, that is scary. Especially considering you may have replaced the wrong part.

_________________
Bill

Image


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Sat Mar 08, 2014 11:52 am
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 06, 2014 2:48 pm
Posts: 12
According to the documentation that comes from Fromel, you can replace the Master pot or the Volume pot. I don't use the drive channel so I decided to replace the Volume pot. The new pot doesn't have the snap in bracket that is soldered to the board, which is tied to R63. So as it stands, one side of R63 is tied to the chassis ground and the other side is not connected to anything (normally connected to the bracket ground).

The amp is working perfectly at the present moment. What is strange though is that only one specific tube works in V1. All others cause an incredibly loud hum. That is what is currently confusing me. Anyone have any thoughts on that?

I know these amps are finicky, but I wanted to try something new which is why I attempted the mod. I like to tinker and I really don't like to rely on others to do the work for me. I will figure it out eventually. I appreciate a community like this that will offer up help.

Thanks


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Sat Mar 08, 2014 2:04 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
mattmcconnell wrote:
According to the documentation that comes from Fromel, you can replace the Master pot or the Volume pot. I don't use the drive channel so I decided to replace the Volume pot. The new pot doesn't have the snap in bracket that is soldered to the board, which is tied to R63. So as it stands, one side of R63 is tied to the chassis ground and the other side is not connected to anything (normally connected to the bracket ground).

The amp is working perfectly at the present moment. What is strange though is that only one specific tube works in V1. All others cause an incredibly loud hum. That is what is currently confusing me. Anyone have any thoughts on that?

I know these amps are finicky, but I wanted to try something new which is why I attempted the mod. I like to tinker and I really don't like to rely on others to do the work for me. I will figure it out eventually. I appreciate a community like this that will offer up help.

Thanks


As has been stated earlier, the clean volume is already an audio taper pot so replacing it with the Fromel pot serves no real purpose. My suggestion would be to put everything dealing with the clean volume pot back to the way it was before and see if that solves your tube problem. I have no idea why only one specific tube works in V1.

_________________
Bill

Image


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Sat Mar 08, 2014 4:08 pm
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 06, 2014 2:48 pm
Posts: 12
Yeah I will put that back in and see what happens. I appreciate the help.


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Sat Mar 08, 2014 5:24 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
mattmcconnell wrote:
Yeah I will put that back in and see what happens. I appreciate the help.


Make sure R63 is connected properly.

_________________
Bill

Image


Top
Profile
Post subject: Re: Hot Rod Deluxe LOUD hum
Posted: Sat Mar 08, 2014 7:45 pm
Offline
Hobbyist
Hobbyist

Joined: Thu Mar 06, 2014 2:48 pm
Posts: 12
Will do :-)


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 35 posts ]  Go to page 1, 2, 3  Next
Go to page 1, 2, 3  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


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: