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Paul Rivera Fender Concert-II compared to Dumble? YES? NO?
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Toppscore



Joined: 29 Aug 2012
Posts: 286
Location: California

PostPosted: Thu Jan 03, 2013 6:48 am    Post subject: Paul Rivera Fender Concert-II compared to Dumble? YES? NO? Reply with quote

PHOTOS BELOW

Hi! I've never played through a Dumble or Trainwreck amp. Last year I purchased a heavily modified 1983 Paul Rivera designed Fender Concert 1x12 60w combo amp with Fender’s spring reverb. Unbeknownst to me, the custom Concert-II amp I purchased was compared to Dumble. I've read several comments about the Concert-II and the Twin Reverb-II being compared to Dumbles and Trainwrecks as being close regarding tones/sounds and the ability to be modified.

This particular custom 1983 Concert-II offers:
1) Most all Lee Jackson modifications
2) Custom “NFB” Negative Feed Back modification with NFB control knob on faceplate panel
3) Channel #1 for Vintage Fender Bassman Tube tones. Think “Strangelhold” by Ted Nugent for clean channel tones when cranked w/feedback. “Compares to a 1960 Fender Twin Amp”.
4) Channel #2 for “Marshall Plexi Over-Drive Crunch" tones”. Think “Pretending” by Eric Clapton with the lead channel cranked w/feedback. Awesome versatility offered by this custom Concert II
5) The NFB Negative Feedback control generates both Fender Twin Amp sounds/tones and Marshall Plexi sounds/tones from this Concert II
6) Celestion G12 Vintage 30 Speaker cone is stamped 444 from the UK, pre-Chinese
7) The Presence Control has been replaced by the “NFB” Negative Feedback control
to manage the amp’s output tube distortion point and to provide touch sensitive feedback
8~ A Fixed Bias Pot was added to adjust the amount of negative voltage when changing power tubes and the voltage test port
9) Output power: 57-watts in fixed bias mode; 30-watts in cathode bias mode
10) An “Impedance Switch” replaces the ground switch giving this Concert-II an added Bias Switch. Able to switch between a fixed-57-watts of output power down 50% to a cathode bias-30-watts of power ~ helps achieve a spongier response
11) Only NOS Allen Bradley or NOS wirewound resistors are installed; new quality electrolytic capacitors with higher power rating specs


*** I purchased this amp for the enormous amount of deliverable tone/sound possibilities.
Following below is an email I received, basically stating this 1983 Concert II is
“so close to a Dumble, it’s scary” “it is worth $2500” and that "Fuchs, Paul Rivera
& many boutique amp mfgs agree with the Concert II comparisons towards Dumble amps".

QUESTION: Since this fantastic forum has major interest towards Dumble Amps and
and Trainwreck Amps, . . . WHAT DO YOU THINK or BELIEVE about Dumble Amps being
compared to Fender production Concert II amps or 1980s Paul Rivera era Fender-II amps???


I own Fender Tweed Brownface Blackface & Silverface amps. Am just now beginning to study
the Fender/Paul Rivera era amps. Thank you for your ideas, thoughts and opinions.


Emailed to me after my purchase discussing my 1983 Concert II amp:
“YOU BOUGHT THAT AMP? NEVER SELL IT! I was SO close to buying it, that it hurts. GodDonYa! That has most all the Lee Jackson mods installed (maybe a couple a bit different). That’s a BEAUTIFUL piece of equipment. Seriously, that’s a $2500 amp. It’s as close to a "boutique Dumble" as you can get. Sell everything else, but keep that Concert II. The Concert II's are the best buy around. I talked to Fuch Amps, some other boutique builders and also emailed Paul Rivera himself (who was kind enough to get back to me). Concert II amps offer the best platform for modifications to DUMBLE-ize ~ much more than any other amp available. The Concert II amp market pricing (IN THEIR OPINIONS) HAS NOT caught up to the boutique market yet (thank god) but it will. Your other 1984 Twin Reverb-II amp head is built so close to a Dumble its scary. Both of your amps are very Dumble like. You’ve some NICE stuff. Good choices.”

_________________
Fan of Fender Trainwreck Dumble


Last edited by Toppscore on Thu Jan 03, 2013 10:57 am; edited 7 times in total
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sepulchre



Joined: 28 Dec 2009
Posts: 861
Location: Way out here (In, USA)

PostPosted: Thu Jan 03, 2013 8:41 am    Post subject: Reply with quote

Congratulations! I'm sure it's a Superb amp, no doubt. But there's something you should know. "NFB" doesn't stand for No Feedback, it refers to the Negative Feedback loop that is part of what gives your amp it's sound quality. Being able to control it is a definite plus, adding to your tonal options.

Just thought you'd want to know.
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Toppscore



Joined: 29 Aug 2012
Posts: 286
Location: California

PostPosted: Thu Jan 03, 2013 10:34 am    Post subject: Reply with quote

sepulchre wrote:
Congratulations! I'm sure it's a Superb amp, no doubt. But there's something you should know. "NFB" doesn't stand for No Feedback, it refers to the Negative Feedback loop that is part of what gives your amp it's sound quality. Being able to control it is a definite plus, adding to your tonal options. Just thought you'd want to know.


I do want to know. Thanks. I will change my notes.

Looking back at my notes from the custom amp builder:

"Negative Feedback: I changed the presence control: Took off the tone capacitor and added a resistor network to adjust the amount of NFB from about 1% to 24%. Negative feedback is from a signal off the speaker tap, injected into the preamp to stabilize the amp, especially in Hi-Fi. Without it you get FEEDBACK, but that's a good thing for guitar. Fender guitar amps use between 8% (Concert) and 12% (Bassman) as do most others. Orange Amps and Trainwreck Amps only use about 4%! This knob now allows you to adjust the amount NFB. By cutting the NFB down to 1% you increase the gain substantially by lowering the point at where the output tubes breakup, and you can get some feedback that enhances the effect. But, with all controls at maximum, one needs to be away from the amp. This helps especially with lower volumes where you still want some cranked tone. Adding more NFB allows a cleaner sound ~ up to a point because all tubes will breakup/distort when enough signal is applied. This helps with lower volumes where you’d still want some cranked tone. The presence control is simply a tone control that adds more mid highs. The Presence is not necessary and the change to the NFB is REALLY nice!

***The difference between early Fender Bassmans & the first Marshalls = speaker polarity: Fenders used speakers that were in phase with their amps. The Bassman’s output is/was reversed polarity and so were the Jensen speakers. Marshall used the SAME schematic but instead, had Celestion speakers, that are forward polarity. That made a bit more distortion and harmonics. It’s the reason there’s a difference in sound between two exact amps. I’ve wired this Concert II's Celestion speaker in reverse to match the first channel and be out of phase with the lead channel. This makes a noticeable difference. It’s very clean on channel #1 & extra crunchy within the lead channel #2. If you’re using an extension cab or extra cab make sure to check the polarity of your speakers to make ensure they all move the same direction as the combo amp's speaker ~ to guarantee a matched sound (use 9v battery, touch the speaker plug pos to pos and see which way the speaker moves. They don’t all move in the same direction."

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selloutrr



Joined: 14 Oct 2007
Posts: 3705
Location: Southern California

PostPosted: Thu Jan 03, 2013 5:46 pm    Post subject: Reply with quote

Great amp, however a dumble it is not.
Rivera concert started life closer to a fender showman which is arguably fenders best design. It's been copied for bass and guitar over and over again. I forget which tube manufacture they licensed it from.
The lee Jackson mods are more Ampeg and Marshall which were both spin offs of hot rod bassman amps.

You have a kicking Texas blues rock amp.

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Reeltarded



Joined: 14 Feb 2009
Posts: 7067
Location: GA USA

PostPosted: Thu Jan 03, 2013 5:57 pm    Post subject: Reply with quote

How come these days when I look at gut shots I just see components to strip out for other amps?

Let me know if you ever want to get rid of the 2-3w CCs! Love those!! lol
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vibratoking



Joined: 10 Nov 2009
Posts: 2215
Location: Colorado Springs, CO

PostPosted: Thu Jan 03, 2013 6:00 pm    Post subject: Reply with quote

I owned the same amp for many years and recently sold it. It did the same thing that many of my other amps already did.

Mine did not sound anything like my Dclone. Yours sounds so heavily modded that it would be very difficult say what it sounds like. How would we compare your one of a kind to anything else?

There is at least one major thread here regarding modding the Concert II into a Dstyle amp. Use the search.

The gutshot is a ratsnest, like all the Rivera Fenders I have seen.

Mine was a good Texas blues amp as mentioned. It was also very hard to set it up so it sounded good clean and OD. It was not a two channel amp IMO because of that problem.

The trick to that amp is to jumper the effects loop and use the extra gain stage. I did not enjoy the OD without the jumper.

Enjoy!
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TUBEDUDE



Joined: 04 Jan 2007
Posts: 241
Location: GA.

PostPosted: Thu Jan 03, 2013 6:22 pm    Post subject: Reply with quote

Are you saying that reversing the leads to your speaker makes the signal "crunchier", or changes it in some fashion? I recall in audiophile circles there is a belief in speaker and signal wires having a preferred direction, or polarity if you will. I find it hard to reconcile this with the fact that the amp signal is A.C. and the signal travels in both directions thru the wire. The only "phase" issues i was aware of were in multiple speaker setups, between several amplifiers, and between channels in most fender 2 channel amps.
I experimented with three of my amplifiers, and found no discernable change after reversing the speaker wires. Is there some consesus on this "effect", or is this audio voodoo.
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Reeltarded



Joined: 14 Feb 2009
Posts: 7067
Location: GA USA

PostPosted: Thu Jan 03, 2013 7:12 pm    Post subject: Reply with quote

I hear at the speed of light. I noticed a blue shift in tone on the push side of one amp. Turns out the couplers had unequal leads. One was 1.616199 × 10-35 meters longer than the other.

Walk the planck.
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xtian



Joined: 19 Apr 2010
Posts: 3220
Location: NorCal

PostPosted: Thu Jan 03, 2013 7:49 pm    Post subject: Reply with quote

Reeltarded wrote:
I hear at the speed of light. I noticed a blue shift in tone on the push side of one amp. Turns out the couplers had unequal leads. One was 1.616199 × 10-35 meters longer than the other.

Walk the planck.


You, sir, are spooky action at a distance.

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jaysg



Joined: 07 Feb 2006
Posts: 1123
Location: Sandy Eggo

PostPosted: Thu Jan 03, 2013 9:44 pm    Post subject: Reply with quote

That chassis has been through the wars...wow. No labels on the front? I put my Soul-Control in the polarity switch hole. Dual bias...good.

It's hard to tell, but it looks like he didn't use the spare half of V5.
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rdjones



Joined: 31 Aug 2010
Posts: 819
Location: Music City, TN

PostPosted: Thu Jan 03, 2013 9:56 pm    Post subject: Reply with quote

Reeltarded wrote:
How come these days when I look at gut shots I just see components to strip out for other amps?

Let me know if you ever want to get rid of the 2-3w CCs! Love those!! lol


Laughing Twisted Evil

rd
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Structo



Joined: 17 Oct 2007
Posts: 14242
Location: Oregon

PostPosted: Thu Jan 03, 2013 9:58 pm    Post subject: Reply with quote

Phasing of the speakers is a controversial topic.
It's been argued to death at places like The Gear Page.

Personally, I like the cone to move out on the positive wave.

Certain amps invert the output from the input, as do most Dumble style amps.

If you don't hear it then it's no sweat.


To the OP, are those wooden Moj0 knobs on the amp?

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rdjones



Joined: 31 Aug 2010
Posts: 819
Location: Music City, TN

PostPosted: Thu Jan 03, 2013 10:11 pm    Post subject: Reply with quote

vibratoking wrote:
I owned the same amp for many years and recently sold it. It did the same thing that many of my other amps already did.

Mine did not sound anything like my Dclone. Yours sounds so heavily modded that it would be very difficult say what it sounds like. How would we compare your one of a kind to anything else?

Yeah, let's hear some sound clips.

Quote:
The gutshot is a ratsnest, like all the Rivera Fenders I have seen.

Rivera had his work cut out for him when he was trying to get the "new sound" using the old wiring techniques.
This is why we make such a big deal about lead dress.

And what happened at the end of the "Rivera Era" ?
Fender started using PCBs.

rd
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iknowjohnny



Joined: 24 Apr 2008
Posts: 1034
Location: los angeles

PostPosted: Thu Jan 03, 2013 10:29 pm    Post subject: Reply with quote

I don't know about your modded one, but i had a rivera designed concert and the princeton one and neither had a distortion channel that could possibly sound remotely like a dumble. This coming from someone who's never played a dumble. So then why would i say that? Because, the concert's distortion was horrid ! If a dumble's OD is remotely as good as it's said to be, there can be no comparison. The clean sound is a different story, and where the concert sounded good. The distortion was one of the worse i've owned, and i've owned a lot of amps in 40 years of playing. the princeton's drive channel was better but still nothing to write home about. As heavily modded as yours appears to be, even if it does sound like a dumble that says nothing about the concert. You can heavily mod most any amp thats somewhat similar (or not even) to a dumble to sound like one. Just depends on how far you wanna go. But the concert was a good fender clean amp, nothing more. The drive channel is just an unfortunate addon.
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ToneMerc



Joined: 26 Apr 2009
Posts: 2824
Location: East Coast

PostPosted: Thu Jan 03, 2013 10:57 pm    Post subject: Re: Paul Rivera Fender Concert-II compared to Dumble? YES? N Reply with quote

Toppscore wrote:


Hi! I've never played through a Dumble or Trainwreck amp. Last year I purchased a heavily modified 1983 Paul Rivera designed Fender Concert 1x12 60w combo amp with Fender’s spring reverb. Unbeknownst to me, the custom Concert-II amp I purchased was compared to Dumble. I've read several comments about the Concert-II and the Twin Reverb-II being compared to Dumbles and Trainwrecks as being close regarding tones/sounds and the ability to be modified.

This particular custom 1983 Concert-II offers:
1) Most all Lee Jackson modifications
2) Custom “NFB” Negative Feed Back modification with NFB control knob on faceplate panel
3) Channel #1 for Vintage Fender Bassman Tube tones. Think “Strangelhold” by Ted Nugent for clean channel tones when cranked w/feedback. “Compares to a 1960 Fender Twin Amp”.
4) Channel #2 for “Marshall Plexi Over-Drive Crunch" tones”. Think “Pretending” by Eric Clapton with the lead channel cranked w/feedback. Awesome versatility offered by this custom Concert II
5) The NFB Negative Feedback control generates both Fender Twin Amp sounds/tones and Marshall Plexi sounds/tones from this Concert II
6) Celestion G12 Vintage 30 Speaker cone is stamped 444 from the UK, pre-Chinese
7) The Presence Control has been replaced by the “NFB” Negative Feedback control
to manage the amp’s output tube distortion point and to provide touch sensitive feedback
8~ A Fixed Bias Pot was added to adjust the amount of negative voltage when changing power tubes and the voltage test port
9) Output power: 57-watts in fixed bias mode; 30-watts in cathode bias mode
10) An “Impedance Switch” replaces the ground switch giving this Concert-II an added Bias Switch. Able to switch between a fixed-57-watts of output power down 50% to a cathode bias-30-watts of power ~ helps achieve a spongier response
11) Only NOS Allen Bradley or NOS wirewound resistors are installed; new quality electrolytic capacitors with higher power rating specs


*** I purchased this amp for the enormous amount of deliverable tone/sound possibilities.
Following below is an email I received, basically stating this 1983 Concert II is
“so close to a Dumble, it’s scary” “it is worth $2500” and that "Fuchs, Paul Rivera
& many boutique amp mfgs agree with the Concert II comparisons towards Dumble amps".

.Thank you for your ideas, thoughts and opinions.


“YOU BOUGHT THAT AMP? NEVER SELL IT! I was SO close to buying it, that it hurts. GodDonYa! That has most all the Lee Jackson mods installed (maybe a couple a bit different). That’s a BEAUTIFUL piece of equipment. Seriously, that’s a $2500 amp. It’s as close to a "boutique Dumble" as you can get. Sell everything else, but keep that Concert II. The Concert II's are the best buy around. I talked to Fuch Amps, some other boutique builders and also emailed Paul Rivera himself (who was kind enough to get back to me). Concert II amps offer the best platform for modifications to DUMBLE-ize ~ much more than any other amp available. The Concert II amp market pricing (IN THEIR OPINIONS) HAS NOT caught up to the boutique market yet (thank god) but it will. Your other 1984 Twin Reverb-II amp head is built so close to a Dumble its scary. Both of your amps are very Dumble like. You’ve some NICE stuff. Good choices.”



1. Concert II or Twin II is not even remotely close to any Dumble voicing or a TW.

2. In reality on this forum which I call the derfinitive public discussion boards on Dumble amps, you will rarely find someone mentioning modding a C2 or even mentioning it's is a good canidate for modding.
FWIW, in the context of some like Mr Fuchs modding these, it's not much of a mod when you gut the chassis and use all your own boards and such, in reality just using the chassis, iron abd cabinet as a donor.

3. I hate to bash a "custom builder", but it looks like he's never seen the inside of a Dumble, who is this guy? Makes you want to put on rubber boots.

TM
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