It is currently Mon Mar 16, 2020 4:11 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 249 posts ]  Go to page Previous  1 ... 7, 8, 9, 10, 11, 12, 13 ... 17  Next
Go to page Previous  1 ... 7, 8, 9, 10, 11, 12, 13 ... 17  Next
Author Message
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Tue Jan 31, 2012 8:16 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
T2Stratman wrote:
bluesky636 wrote:
Butterscotch wrote:

If all else fails, check the user manual! :lol:


User manual?!?!?!?!? I don't need no steenking user manual. I'm an engineer! :lol: :lol: :lol:





Actually, I do read every user manual. Even the one that come's in a new car. :lol:


Careful there Bill, they might take your Man Card if you keep admitting to reading those instruction manuals! :lol: :lol: :lol:

And we are waiting patiently to hear that thing on 12 :!: :!: :!:

T2


Its Ok. I never ask for directions or where to find somthing in the store. It all evens out. :lol:

I promise to record something this weekend. I don't want the police banging on my door at 10:00 at night. :(

_________________
Bill

Image


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Tue Jan 31, 2012 8:33 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Mar 01, 2011 3:10 pm
Posts: 5646
Location: Gateway to the West
Bill...It is clear you TOTALLY understand the Man Card! All that is missing is lighting up the tires once in a while! :wink:

T2

_________________
-----------------------------------------------------------
What time is it? It's Fender Time.


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Wed Feb 01, 2012 1:22 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
T2Stratman wrote:
Bill...It is clear you TOTALLY understand the Man Card! All that is missing is lighting up the tires once in a while! :wink:

T2


I do my best to keep up. :lol:

_________________
Bill

Image


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Wed Feb 01, 2012 4:55 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Mar 01, 2011 3:10 pm
Posts: 5646
Location: Gateway to the West
bluesky636 wrote:
T2Stratman wrote:
Bill...It is clear you TOTALLY understand the Man Card! All that is missing is lighting up the tires once in a while! :wink:

T2


I do my best to keep up. :lol:


Not to get too far off topic, but we have an annual Man Cruise in our Vette Club...no women! We go to car museums, hot rod shops, etc, around the St Louis area and then end the day with a dinner and the Man Card Ceremony!

You figuring out that recorder yet? Hope so, can't wait to hear that puppy!

T2

_________________
-----------------------------------------------------------
What time is it? It's Fender Time.


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Wed Feb 01, 2012 5:33 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
T2Stratman wrote:
You figuring out that recorder yet? Hope so, can't wait to hear that puppy!

T2


Well, I've figured out how to turn it on. :oops:

This weekend. I promise. :lol:

_________________
Bill

Image


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Wed Feb 01, 2012 5:41 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
On a more serious note, I discovered today I had installed the wrong fuse after replacing the power supply caps. :shock:

I looked at the fuse that blew and bought a 3A 250 VDC fuse. The other day I turned the amp on and the new fuse blew. I checked everything over and found nothing wrong, so I put in another fuse and the amp powered up OK. I did notice a couple of times though, that the pilot light flickered slightly when I powered up. :?:

Today I was looking at the schematic and saw that the fuse called for was a 3A 250 VDC SLO-BLO fuse. I had installed a fast blow fuse and the current in-rush caused it to blow and the pilot light to flicker. :oops:

A quick trip to Radio Shack secured the proper fuses. No more pilot light flicker. Guess it pays to read the schematic even after all work is completed. :lol:

_________________
Bill

Image


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Wed Feb 01, 2012 8:52 pm
Offline
Roadie
Roadie
User avatar

Joined: Tue Jun 28, 2011 11:54 am
Posts: 271
Location: Baytown, TX
bluesky636 wrote:
T2Stratman wrote:
You figuring out that recorder yet? Hope so, can't wait to hear that puppy!

T2


Well, I've figured out how to turn it on. :oops:

This weekend. I promise. :lol:


That's using those engineering skills! :lol: :lol:

Glad to hear your working the bugs out of it! :)

_________________
2000 American Deluxe Stratocaster
2011 Gibson Les Paul Trad Pro 50's
2007 Epi Les Paul Custom
90's ESP Eclipse
JH-1B Jimi Hendrix Crybaby
Analogman KOT
Korg Pitchblack
Boss NS-2 PH-2
Blues Deluxe Reissue
1999 & 2007 Marshall TSL 100 w/1960BV cab


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Wed Feb 01, 2012 9:36 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
I do have one bug that is bothering me.

I am getting a scratchy sound while the amp is sitting idle with everything plugged in but not being played. It is sort of a crackling/scratchy sound that is distinct from the normal background hiss. It also appears to get slightly worse as time goes on. You can't hear the noise while actually playing, though.

I do know that the Presence circuit design allows a DC path to ground through the pot which causes a scratchy noise when the Presence pot is turned. The idle noise sounds just like that. I have the parts on order to convert the old Presence pot circuit to that of the 59 Reissue Presence circuit which blocks the DC path to ground. You can see the difference in the two schematics.

https://taweber.powweb.com/store/5f6a_schem.jpg

http://ampwares.com/schematics/59_bassman_manual.pdf

I am thinking that this noise is also a DC noise and if changing the Presence circuit doesn't cure it, I'll check the coupling and bypass caps for any DC where it shouldn't be. Oh, and before anyone asks, I did swap each preamp tube with no difference.

_________________
Bill

Image


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Thu Feb 02, 2012 5:17 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
Anyone have any other thoughts as to the cause of the scratchy/crackling noise mentioned in my last post could be? It definitely gets worse as the amp heats up, but has yet to cause the camp to become unplayable.

_________________
Bill

Image


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Thu Feb 02, 2012 5:52 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Blue, you eaten Chinese or Japanese lately? :?:

Sounds like a bad resistor. And it gets worse as it heats up. You need one WOODEN chopstick. Pull amp. Plug in the speaker. No input. Crank the volume slightly, until you can hear the scratchy, crackling noise.

Now, carefully tap each component. Resistors, solder points, caps, jacks, etc. You want to see if you can change the noise. Either make it worse or louder or something that would indicate your culprit.

Good luck. BTW... keep your free hand OFF the chassis when doing this test. Lest you become the path of least resistance to ground. :cry:


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Thu Feb 02, 2012 5:57 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sat Mar 20, 2010 2:30 pm
Posts: 792
Location: A Land Downunder
Hi Bill,
I was going to suggest preamp tubes but you tried that already, as I had a similar sounding issue with an NOS Philips 12AX7, it sounded like frying bacon, even when I swapped them around, but I found which one by using the chopstick method Beemer describes, gently tapping each tube. Instead of just swapping the preamp tubes have you tried replacing them with other ones just to see?


Snowy


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Thu Feb 02, 2012 7:28 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
BMW2002Ti wrote:
Blue, you eaten Chinese or Japanese lately? :?:

Sounds like a bad resistor. And it gets worse as it heats up. You need one WOODEN chopstick. Pull amp. Plug in the speaker. No input. Crank the volume slightly, until you can hear the scratchy, crackling noise.

Now, carefully tap each component. Resistors, solder points, caps, jacks, etc. You want to see if you can change the noise. Either make it worse or louder or something that would indicate your culprit.

Good luck. BTW... keep your free hand OFF the chassis when doing this test. Lest you become the path of least resistance to ground. :cry:


I bought a set of chopsticks from Weber when I ordered the amp. :lol:

I'll give that a try. I won't be working on the amp again until the parts for the Presence control mod come in, probably in another week, so I will try your suggestion then. I'll also be checking the bias at that time now that the tubes have gotten a few hours on them.

_________________
Bill

Image


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Thu Feb 02, 2012 7:32 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
No457 Snowy wrote:
Hi Bill,
I was going to suggest preamp tubes but you tried that already, as I had a similar sounding issue with an NOS Philips 12AX7, it sounded like frying bacon, even when I swapped them around, but I found which one by using the chopstick method Beemer describes, gently tapping each tube. Instead of just swapping the preamp tubes have you tried replacing them with other ones just to see?


Snowy


It is not the preamp tubes. I actually did replace the tubes in the amp with another set of known good tubes (except the power tubes as I don't have any spare 6L6GCs). I tried three different 12AY7s as well as a 5751 in V1 along with different 12AX7s in V2 and V3. It made no difference.

_________________
Bill

Image


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Fri Feb 03, 2012 1:17 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Good luck with the fix-it. It's amazing how many amps I've fixed using chopsticks and De-Oxit D-5 contact cleaner. Only the highest tech stuff for me!

:D


Top
Profile
Post subject: Re: My Weber 5F6A Bassman Build-Up Thread
Posted: Fri Feb 03, 2012 6:29 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
OK. I tapped every single component, solder joint, tube, wire, etc. that I could get to without taking the amp apart. Here is what I found:

The only point in the amp that reacted to my tapping were the input jacks. Particularly, it seems, the Bright input.

Image

Image

Side note: I just noticed that the schematic and the wiring diagram differ as far as which set of input jacks the 1M resistor is wired to. I wired mine per the schematic which appears to be correct as far as which jack is high level and which is the low level input.

Anyway, I found that tapping lightly on the tip terminal of both normal inputs did not result in any significant noise. However, tapping lightly on the tip terminal of the Bright input jacks, and in particular, the High level input, would result in a loud, crackling noise. Pushing on the tip terminal to cause it to break contact with the switch contact caused the same noise. Also, tapping on the 1M resistor on the high level Bright input would cause the same noise. It was interesting to note that once the noise started, tapping on the tip terminal of the high level Normal input would cause the noise to occur with that input. Tapping the Bright jack tip terminal or 1 M resistor would cause the noise to stop.

So, it would appear that I MIGHT have a bad 1M resistor on the Bright input, or the tip and switch terminals are not making good contact. I can squeeze the terminals together more tightly (easy to do) or change the 1M resistor. So before I do either (after dinner) which seems to be the most likely cause of the noise? I should note that the amp has been on for almost 2 hours and is making a very slight crackling noise which gets worse if I tap on the Bright input tip terminal.

I'll be back after dinner.

_________________
Bill

Image


Last edited by bluesky636 on Sat Nov 03, 2012 11:26 am, edited 1 time in total.

Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 249 posts ]  Go to page Previous  1 ... 7, 8, 9, 10, 11, 12, 13 ... 17  Next
Go to page Previous  1 ... 7, 8, 9, 10, 11, 12, 13 ... 17  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: