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Post subject: Ramparte Amp imperfect by design or laziness?
Posted: Wed Jun 03, 2015 6:21 am
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I was looking for a clean but soulful "livingroom" amp and found a store that had a handfull of Rampartes in stock at a good price so I bought one.

I knew tonally what I was getting and I am happy with the clean tone, but that 60hz hum is really annoying me.

Upon inspection and searching the web to confirm my findings, the Power and OP transformers really are too close together and I *think* the power filtering might be a little under done.

If this was branded with a far east off brand I wouldn't bat an eye at the design flaw(s), but this is supposed to be a Fender product manufactured in the far east. Keeping 6" between transformers doesn't cost more and using a properly sized filter cap might be pennies more more per unit if at all.

So I am left with the dilemma of "do I fix it and kill the warranty or do I live with the hum?" and the question, "Was this design laziness/incompetence, or an intentional act of design? (making sure a low cost amp doesn't rival amps like the Blues jr)"


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Wed Jun 03, 2015 6:42 am
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All I know about the Ramparte is that the other guitar player in our old band had one for short period of time and it was one the the most annoyingly noisy SOB's I've ever heard!


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Wed Jun 03, 2015 9:18 am
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Blind Gilbo wrote:
All I know about the Ramparte is that the other guitar player in our old band had one for short period of time and it was one the the most annoyingly noisy SOB's I've ever heard!


+1!

Take it back to the store and get yourself a real amp.

Arjay

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"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


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Wed Jun 03, 2015 2:23 pm
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I wanted mine to work out but the hum was a deal breaker. Took mine back and went with a Tweed Blues Junior. Very happy now.

Jay


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Wed Jun 03, 2015 7:49 pm
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Class A amps do tend to hum more than class AB. The OT of an AB stage cancels hum.
But this model has more going on than that
This problem was discussed on this forum last year.
viewtopic.php?f=2&t=94037
In those posts, he refers to an Ebay ad that discusses the cure.
The post is still up, but the part that is interesting is here:
Another 'Issue' with the Stock Amp is the HIDEOUS Level of Background Noise (Severe Buzz and Hum). There are three main problems (1) The Output Transformer (OPT) is too close to the Mains Transformer and Causes a Pronounced 'HUM' when the Amp is first switched on, even before it warms up - Simple Fix, Move the OPT away from the Mains Transformer - Done. (2) Not enough Smoothing in the Power Supply which causes the Amp to 'BUZZ' - I have Corrected that. (3) A Design Error on the Main PCB has caused an 'Earth Loop' in the Circuit, which is responsible for most of the Buzz and Hum in the Amp. Unbelievable in a Fender Amp and totally unacceptable. Fender know there is a problem because they have made a 'Half-Ass' effort to correct it by cutting PCB Tracks here and there and adding lengths of wire to the Board, with no success. It took awhile to Find the Error, but I found it and corrected it. The Result - The Amp is now 'SILENT' - NO Background Noise, it's so Quiet that it is difficult to tell if the Amp is On or Off.

The unfortunate part is that there is no description of the exact fix.


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Thu Jun 04, 2015 1:35 am
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TimsAudio wrote:
Class A amps do tend to hum more than class AB. The OT of an AB stage cancels hum.
.


It is push-pull output cancell hum .

If shematic is right ? * ;
Ramparte in single end output and no heater center tap ; both make hum .
No input shorting jacks make noise too

* Schematic ;
http://www.tdpri.com/forum/amp-tech-cen ... matic.html


Last edited by stratele52 on Thu Jun 04, 2015 2:04 am, edited 1 time in total.

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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Thu Jun 04, 2015 2:01 am
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Stratele, something interesting about that schematic. The amp doesn't seem to have input jacks that ground the leads, when nothing is plugged into it. Wonder if this was overlooked by the guy who drew the schemo?


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Thu Jun 04, 2015 2:06 am
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BMW2002Ti wrote:
Stratele, something interesting about that schematic. The amp doesn't seem to have input jacks that ground the leads, when nothing is plugged into it. Wonder if this was overlooked by the guy who drew the schemo?



+1

Tthat is why I wrote , " if schematic is right ? "

Did he forget heater center tap too ?


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Fri Jun 05, 2015 8:09 pm
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The schematic looks in error to me,
Why is R33 connected to the cathode of the output tube 6L6?
and R34 goes to B+1.

Whatever, it doesn't matter. Its not a Fender schematic.
Maybe try some different preamp tubes to reduce overall noise.


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Sat Jun 06, 2015 1:22 am
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jackhammer wrote:
The schematic looks in error to me,
Why is R33 connected to the cathode of the output tube 6L6?
and R34 goes to B+1.

Whatever, it doesn't matter. Its not a Fender schematic.
Maybe try some different preamp tubes to reduce overall noise.


+1
Yes lot of error on this schematic , we must forget it .

Anybody have the right one ?


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Sat Jun 06, 2015 1:50 am
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stratele52 wrote:
jackhammer wrote:
The schematic looks in error to me,
Why is R33 connected to the cathode of the output tube 6L6?
and R34 goes to B+1.

Whatever, it doesn't matter. Its not a Fender schematic.
Maybe try some different preamp tubes to reduce overall noise.


+1
Yes lot of error on this schematic , we must forget it .

Anybody have the right one ?


I think it's significant that no "official" servicing schematic seems to be available, nor has any amp designer had the stones to step up and admit that they were responsible for creating such an unmitigated piece of crap. I guess the days of legendary engineers like Leo Fender himself, Ed Jahns, Paul Rivera, Bruce Zinky, et al who were proud of their work is over. I suspect we'll see more of these disastrous orphans released for sale in the future......

:roll:

Arjay

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"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


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Sat Jun 06, 2015 7:44 am
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I don't know how noisy it really is. It can't be that bad.

If I owned one, I'd probably keep it. I wouldn't give up on it. It’s a Fender. It seems like an amp that may have a short production run, if they are still in production? I mean it's stylish in a way. I like the looks better than the Excelsior. Funny thing is I was considering buying a Vaporizer, ha ha, but I didn't. I missed out. Perhaps Ebay will have some good deals.


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Sat Jun 06, 2015 4:02 pm
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I'm sure there's an accountant at Fender who's proud of the Ramparte.
But as Hammer says, "It's a Fender". Ya can't just send it to the pound or put it out of it's misery with a 12 Guage. It's just gonna sit in the closet and occasionally remind you of it's missed potential.
Yea, it just needs a little lovin to set it straight. And over time, techs will figure out how to make them sound OK. It's not like this is Fender's first problem child.


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Sat Jun 06, 2015 4:16 pm
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TimsAudio wrote:
It's not like this is Fender's first problem child.


It seems as though that's all they build these days.

There isn't one -- NOT ONE -- contemporary FMIC amp that I'd consider for professional use. I don't trust them and I won't buy them.

Arjay

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"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


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Post subject: Re: Ramparte Amp imperfect by design or laziness?
Posted: Sun Jun 07, 2015 8:55 am
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Ya, they sure don't build em like they used to. Remember when you could throw your phone down on the ground and it wouldn't even rip out the cord?
With your arsenal of amps, why buy anything else. But for the kids...
I'd rather see them buy a humming tube amp than a transistor anything. At least that can be fixed.


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