It is currently Mon Mar 16, 2020 10:03 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 12 posts ] 
Author Message
Post subject: Sick Prosonic
Posted: Mon Jan 06, 2014 4:45 am
Offline
Hobbyist
Hobbyist

Joined: Mon Jan 06, 2014 4:16 am
Posts: 2
I have a 1997 Red Prosonic which I have owned for 6 years. I have gigged with it extensively and really like the amp but decided to make some changes. I read somewhere that Bruce Zinky had originally wanted these amps to have a single 12" and decided to swap out the baffle board and go with a Weber Ferromax. I've always liked Weber speakers and had good luck with them. Now the fun comes in. The tech I've used since dirt has always been the go to guy or Guru that all the serious players in my area go to and after a B.S. session, he talked me into getting rid of the effects loop and the power switch in the back, telling me it would simplify the circuit. He also suggested swapping out the PT and choke with Mercury Magnetics. OK, he's the tech and knows his stuff so why not.
Well he does all this and charges me almost nothing over parts cost because of our friendship and all is well with the world for about three to four months when I take it to a private party gig and the thing starts sounding like it's gagging on something even at clean settings. So I take it back to him and tell him no rush as I have other amps to use and I want it done right. Roughly one year later and he can't find a thing wrong with it. Speaker is fine, Tubes were swapped to make sure they were ok, supposedly all voltages and tolerances are good so He hands it back with a "sorry, I don't know what it could be" and fortunately no bill. Does anyone have any ideas as to what to check on this or know anyone who is trustworthy and not a financial rapist in either the Pocono area or Lehigh Valley area that I could trust to take it to. Heck, I'll even go into Northern Jersey if the Dude knows his stuff. I do have it up for sale on Craigslist and will most likely be putting it back on Ebay if I don't get some help soon. By the way, I emailed Zinky and he blew me off. Real nice. Any help would be appreciated.
Thanks.


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Sick Prosonic
Posted: Mon Jan 06, 2014 9:42 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
If your "tech " can't find why , sorry but he is not qualified.
And hoow yourself can you fix the amp ?

Hard to fix an amp by the web witout listening the amp and seeing inside .

Could be many thing , first check what are the mod he do and how he do the work .

Pictures please and sound on Youtube .......

Or find a qualified tech .


Top
Profile
Post subject: Re: Sick Prosonic
Posted: Mon Jan 06, 2014 10:22 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
Do the amp's symptoms manifest regardless of which rectifier mode is used?

If so, the issue may lie there.

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: Sick Prosonic
Posted: Mon Jan 06, 2014 12:58 pm
Offline
Amateur
Amateur
User avatar

Joined: Sun Oct 25, 2009 12:56 pm
Posts: 103
The first problem you have is trying to change anything about the prosonic! Its a perfect amp the way it is!

_________________
Image


Top
Profile
Post subject: Re: Sick Prosonic
Posted: Mon Jan 06, 2014 1:24 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Jan 06, 2014 4:16 am
Posts: 2
I would agree that he is not a qualified tech if it weren't that I've known this man for well over ten years and all the pros within a 50 mile radius use and trust him.
I do agree that fixing an amp over the internet is like calling your doctor and saying "Doc, I'm sick; what's wrong with me.
As it happens I couldn't sleep last night and sat here researching everything I could think of that might be the problem.
What I found that sounded closest to the symptoms I have was the phase inverter; either the quality of the tube itself or something in the phase inverter circuit.
I did talkto my guy this morning and he happened to get another Prosonic in last week for a different type of repair job but sounding the same. When the tech brought it to his attention, he said it was like that from the time he bought it. I just thought maybe someone else had experienced something similar. I will make a recording asap and put a link to it.
Thanks for your responses and to the person from France; no big deal about your English.
At least you took the time to answer.


Top
Profile
Post subject: Re: Sick Prosonic
Posted: Mon Jan 06, 2014 1:48 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
Maxxsoup3 wrote:

Thanks for your responses and to the person from France; no big deal about your English.
At least you took the time to answer.



If you talk about me, Province de Quebec is not in France , we are neighborhoud I guess. I live in Canada. There are a lot French speaking people in many country :lol:


Top
Profile
Post subject: Re: Sick Prosonic
Posted: Mon Jan 06, 2014 4:42 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
gregbluesjr. wrote:
The first problem you have is trying to change anything about the prosonic! Its a perfect amp the way it is!


+1

I always thought so too.

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: Sick Prosonic
Posted: Thu Feb 06, 2014 2:09 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Jul 16, 2007 4:18 pm
Posts: 46
I realize this may not be the advice you're hoping for, but in situations like this where the real answer is unknown, I personally would locate an authorized Fender amp technician, via the Fender web site or a call to FMIC, and get it over with by having said authorized tech correct the problems. Not just a qualified tech, but an *authorized* tech.

If you did find a possible answer on the web, who would you take it to? Back to your long time friend? You'd just be asking for trouble again, no offense.

I own a Prosonic combo and had it serviced once by an authorized tech. It was a long time ago, but he made some reference to the fact that this particular amp is very much unlike any other Fender amp in terms of design. For that reason alone I wouldn't trust mine with anyone other than an authorized tech. You might have to pay full dollar, but in my opinion it's a worthy amp.


Top
Profile
Post subject: Re: Sick Prosonic
Posted: Thu Feb 06, 2014 2:20 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
divebomb wrote:
I own a Prosonic combo and had it serviced once by an authorized tech. It was a long time ago, but he made some reference to the fact that this particular amp is very much unlike any other Fender amp in terms of design. For that reason alone I wouldn't trust mine with anyone other than an authorized tech. You might have to pay full dollar, but in my opinion it's a worthy amp.


Abso-tively posi-lutely +1000!

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: Sick Prosonic
Posted: Fri Feb 07, 2014 6:44 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Hi Maxxsoup3,

Just something to consider, but the tube selection for V3 could be important, because half of that tube is used as a Cathode follower. Some tubes do not do well as a Cathode follower, even though the tube itself could be a perfectly functioning tube. Depending on exactly how the effects loop was "removed", this could be an even more critical position.

I really don't see how removing the effects loop could "simplify" the circuit that much. I can see however, how mucking with the loop could exacerbate the already finicky position. I don't have any personal knowledge of which tube types do not work well in Cathode follower positions, other than reports that some tubes such as Sovteks do not work well there. You might want to try several different, high-quality tubes in the V3 position.

Do you have any info as to how the loop was "removed"? Was V3 removed altogether, components removed, how the circuit was rewired, etc? If V3 was removed/bypassed, this could also be a problem with the impedance matching going into the PI.

_________________
---> "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: Sick Prosonic
Posted: Wed Apr 30, 2014 6:55 am
Offline
Hobbyist
Hobbyist

Joined: Wed Apr 30, 2014 6:46 am
Posts: 1
I talked to someone who did a similar mod with a similar problem. The default impedance is 16ohms. However, it is listed in the manual that by plugging directly into the ext. jack, it puts it into 8ohms. This is an odd thing, as most fenders that pro techs see are 8ohm, with a 100% mismatch tolerance. This is NOT one of those amps. Doing this FIXED the issue, as his Weber was 8ohm.


Top
Profile
Post subject: Re: Sick Prosonic
Posted: Wed Apr 30, 2014 7:10 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
gnuyu2 wrote:
I talked to someone who did a similar mod with a similar problem. The default impedance is 16ohms. However, it is listed in the manual that by plugging directly into the ext. jack, it puts it into 8ohms. This is an odd thing, as most fenders that pro techs see are 8ohm, with a 100% mismatch tolerance. This is NOT one of those amps. Doing this FIXED the issue, as his Weber was 8ohm.


Does the mod include changing rewiring of the secondary of the output tranny? I kinda doubt that if there were a serious impedance mis-match, that the amp would sound fine for awhile (post mod). Then, in 3-4 months sound very bad.

Interesting...


http://bmamps.com/Schematics/fender/prosonic.pdf


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 posts ] 

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: