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Fender 212r Upgrades for Tone

Started by NewGuy101, January 02, 2011, 08:40:38 PM

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bry melvin

I for one can't afford the "American made" versions of some guitars I want to use (one's I used on my album would have cost 9000+. I learned to repair guitars and set up a shop so I could do so. I've made my steel and two of the guitars I record with so far.

That aside Carvin is mostly US made. Also Fender Mexican products are a good idea. Every Mexican that can get decent work is one less dying crossing the desert where I live. Had some knock on the door late last night apparently in trouble and asking for food water and for us to call the "migras" It got cold here in the desert this week.

The Fender amps or at least their chassis broken show up often on auction sites. I bought several for my grandkids often nothing to fix except jacks or blown output transistors.  (I've got an FM65 on the way now and have bought 25r amps for 9Dollars.)

joecool85

Quote from: bry melvin on January 04, 2011, 11:52:18 AM
I for one can't afford the "American made" versions of some guitars I want to use (one's I used on my album would have cost 9000+. I learned to repair guitars and set up a shop so I could do so. I've made my steel and two of the guitars I record with so far.

That aside Carvin is mostly US made. Also Fender Mexican products are a good idea. Every Mexican that can get decent work is one less dying crossing the desert where I live. Had some knock on the door late last night apparently in trouble and asking for food water and for us to call the "migras" It got cold here in the desert this week.

The Fender amps or at least their chassis broken show up often on auction sites. I bought several for my grandkids often nothing to fix except jacks or blown output transistors.  (I've got an FM65 on the way now and have bought 25r amps for 9Dollars.)

What auction sites are you using?  eBay?  The Richmond guitar I'm interested in is the Empire, it sells for about $500 USD.  Pretty good deal if you ask me, and it is made in Canada in a small town about 4 1/2 hours from my home in Maine.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

bry melvin

I use ebay and one local here in AZ sponsored by a TV station. I also get broken stuff from Guitar Center Tucson and Superpawn which although is in Tucson also puts stuff on ebay.

For people here that want low power home amps for starter project riceagemusic often sells lots of 4 or more guitars and Fender Epiphone etc paractice amps on ebay. Good source for starting projects. The also sell guitars that can be repaired...lot of broken headstocks bad neck sets etc. Titebond and homeade jigs and a steam jet can salvage a lot of guitars.

Enzo

Sorry.  yes, the amps are certainly repairable to an individual.  I mention this only to point out that there are not going to be ANY premium parts in the amp.  Fender considers them disposable.  I don;t know what they do with them, all I know is the call tag for the dud sends it to Canada.  I am in Michigan which is very close to Ontario, so someone in Texas could conceivably send them elsewhere.    I seem to recall someone buying dead amp electronics by the pallet, possibly from fender, but I don;t know.  I have no interest in obtaining bulk blown stuff to fix and resell.  it might pay off for someone motivated.

The economics is simple, it costs Fender less to replace the amp than to pay me to fix it.

J M Fahey

In the late 90's, Import Music, the official Argentine importer of Marshall, Peavey, and many others, stopped paying Marshall (don't ask), and the service backup, specially parts, dissapeared.
They asked me to "improvise, do whatever you can" to repair their stuff.
I wasn't much interested because I prefer designing and building, but told them I might take it if they set up batches for me.
They called me when they had about 50 Valvestate 8080 in a warehouse.
After 3 or 4, problems started repeating themselves, I "almost" didn't need to measure, just replace parts, sort of.
I repaired all 50, in a single day, it was a good deal both for me and Import Music.
*Maybe* that guy in Canada is doing something similar, then selling them as refurbished or through EBay.
It pays if you spend very little time on each one; parts are not the problem.
What were the problems?: mostly cracked PCBs close to pots, switches and jacks; a few burnt outputs where I replaced the "unavailable" BDV something or *T "Marshall" with TIP14x, a couple unavailable (way back then) M5401, where I "stole" the one used to switch Reverb to replace a channel switching one, replaced it with 1/2 TL072, "dead bug" mounted, and added a FET to accomplish the actual switching.
Oh well.

joecool85

Quote from: J M Fahey on January 05, 2011, 08:49:25 AM
In the late 90's, Import Music, the official Argentine importer of Marshall, Peavey, and many others, stopped paying Marshall (don't ask), and the service backup, specially parts, dissapeared.
They asked me to "improvise, do whatever you can" to repair their stuff.
I wasn't much interested because I prefer designing and building, but told them I might take it if they set up batches for me.
They called me when they had about 50 Valvestate 8080 in a warehouse.
After 3 or 4, problems started repeating themselves, I "almost" didn't need to measure, just replace parts, sort of.
I repaired all 50, in a single day, it was a good deal both for me and Import Music.
*Maybe* that guy in Canada is doing something similar, then selling them as refurbished or through EBay.
It pays if you spend very little time on each one; parts are not the problem.
What were the problems?: mostly cracked PCBs close to pots, switches and jacks; a few burnt outputs where I replaced the "unavailable" BDV something or *T "Marshall" with TIP14x, a couple unavailable (way back then) M5401, where I "stole" the one used to switch Reverb to replace a channel switching one, replaced it with 1/2 TL072, "dead bug" mounted, and added a FET to accomplish the actual switching.
Oh well.

Sometimes your experience overwhelms me, Juan.  You make it sound like it's no big deal doing all those repairs.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

mojah

I've had to play through one of these before... The clean channel isn't that bad but
the speakers are really upper midrange spikey. I've had to keep the treble at 2. I'm not a fan of those fender or PV Eminence speakers myself. You could for really cheap money put a low pass filter before the speakers to tame some of that harsh high end. I've done it before to SS amps, it will work. Figure a cutoff frequency of 3k or so. This article is from a recording mag and it's for an 8ohm load, you'll have to calculate for a 4ohm load:

THE FILTER FACTOR
Guitar amp purists have their speaker faves for good reason: They can drastically affect the amp tone. Some are bright while others are warm and mellow. This next pair of mods will tame any harsh-sounding guitar amp simply by applying readily available crossover components. Do you see where I'm going with this? Not much fidelity is needed from a "full-range" 10-inch woofer, so I installed a passive 6dB/octave filter — half of a two-way crossover network. I made note of the values needed to cover a frequency range between 1.8 and 4 kHz, and then found the nearest standard inductor at www.mcminone.com (part number 50-3019), a "choke" in the form of a 0.5-milliHenry (mH) air-core bobbin inductor.
There's a handy online crossover calculator at www.the12volt.com/caraudio/crosscalc.asp#cc, a car audio Website. After some ciphering, I determined the roll-off would begin around 2.5 kHz, so that 5 kHz would be down 6 dB. You'd think this was too low, but it was very effective and made the mic choice much less critical.

The schematic is available on the Fender website. You could mod the preamp, change the slope and response of the tone stack, roll some different opamps in. I like BurrBrown opa2607 in my PV SS amps. It's all up to what you want to do and how much time you want to put into it.  Fender is cheap they don't want to pay to fix them, doesn't mean they can't be fixed.

J M Fahey

Hi, joe cool, thanks, you'll make me blush.
The key here is that they were all "the same" amplifier, same version, everything, and problems repeat a lot.
The problem was diagnosing the first few.
The overwhelming quantity were cracked tracks *just* where they reach the pot/switch/jack pad.
They had set the PCB drawing program to very thin traces, good in PC motherboards or VCRs but not on Guitar amplifiers.
JCM900 also had the same problem, although their boards were somewhat better mounted.
Fenders from that era too (M80, etc.).
Typically the round solder pad receives molten solder; when it cools it contracts and tries to make the pad smaller, creating pull against the colder, thin track, which to boot reaches the pad at a right angle, forming two "arrowheads" pointing to each other. It's very easy for a hairline crack to appear from one to the other.
Worst part is that when you press it with the multimeter probe, it may show continuity because you are slightly bending the board and closing the gap.
Peaveys always used much thicker tracks, also kept hand-drawn PCBs much longer than others.
Curiously, Plexis from that same era did not have that problem, I think they kept using "legacy" board designs, simpler and more reliable.
I always use thick tracks, usually 50 mils; maybe 30 mils minimum for less than 1/2 inch  to reach a base on "the other side" of a transistor, 100 mil component pads; 125 or 150 mil ones for external wire connections, etc.
.
Hi mojah. Curiously, Goodmans in their early 70's catalogs suggested using lowpass filters between SS amplifiers and their MI speakers.
If I remember well, they were around 4 or 5 KHz.

joecool85

Quote from: mojah on January 05, 2011, 02:11:17 PM
I've had to play through one of these before... The clean channel isn't that bad but
the speakers are really upper midrange spikey. I've had to keep the treble at 2. I'm not a fan of those fender or PV Eminence speakers myself. You could for really cheap money put a low pass filter before the speakers to tame some of that harsh high end. I've done it before to SS amps, it will work. Figure a cutoff frequency of 3k or so.


Great first post!  Welcome to SSG (although I noticed you actually signed up 2 years ago).
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

NewGuy101

Wow! A lot of responses. I have one question as people talk about the fender preamp. Where is this located because there is a metal cover in the cabinet area that has 2 input spots with a red cable and a white one like you use for a tv. Also, does anyone exactly know what the fender speakers are based off of in this model? I have looked at weber Chicago 12 ceramic speakers that look nice. What is more important, speakers or preamp? What would the preamp plug into? Thanks for answering all the questions1

bry melvin

#25
if you're talking about red and white RCA jacks going to a box in the speaker cabinet area....that is the reverb


If you look at the schematic...the preamp is everyting from the input to where the preamp out and power in jacks are... I don;t have one here currently but if you follow that schematic you can figure out which are preamp parts.

Enzo

I don't know that the speakers in the amp are "based" upon anything.  Well, other than generic "guitar speaker."  I suspect they have relatively high efficiancy to make the little amp sound louder without having to make the circuit beefier.

mojah

Newguy, The preamp will be on the circuit board mounted inside the chassis. Some other posters have commented on the build quality of the board being fragile. I guess we assume you have some electronics experience. If you haven't like replaced caps on a computer motherboard or modded some stopboxes before practicing on your working amp may not be the best idea.
Why don't you  try and borrow a cabinet from somebody and make up a cord to plug it in to try some different speakers out 1st if that is what your gravitating to. A couple of insulated spade crimp connectors to plug into the wiring that goes to your speakers now. You could use on old speaker cord for the 1/4" plug and wire. Tape up the unused pair Different speakers will make the amp sound "different", better is kinda subjective.
If your confident with your soldering/desoldering skills get the schematic from the fender website and go at it. Sockets help a lot. A TL072 opamp starts the preamp out and is pretty much the entire clean channel. Duncan's amp tools will help with the tonestack. There's a ss amp book on this site that's a good read too.

I know I've been a member for a while... I try not to post on old threads (although I've seen a quite few I like)  and be a good lurker... Thanks Guys :)

sustain

I had gotten a fm212r a while back.  I needed a new amp that would be giggable, but I also did not have a budget.  I don't care what anyone says, it's a decent amp, especially for the price.  I actually ended up getting a second one off craigslist for 100 bucks.  Recently, a roommate of mine gave me a cabinet that had Avatar Celestion 30s.  I had kept the cabinet around just in case I found a head I wanted, but I really just don't have the extra money laying around to do that (perhaps I would have a head if I stopped getting effects pedals).  I put Celestions in one of the amps and was able to do a side by side test.  The difference was incredible.

I've never used the onboard distortion, I purchased an Electo Harmonix, English Muff'n tube distortion pedal.

My effects set up is: EHX English Muff'n > Boss GE-7 EQ > BBE Sonic Stomp > Ernie Ball Volume Pedal >Boss Ch-1 Chorus > EHX Stereo Memory Man with Hazarai


J M Fahey

Yes, those amps *are* good, and basically the same as other Fenders.
The distortion is somewhat iffy but you solved that.
The difference between a Celestion or "good" Eminence and a cheap generic speaker is astounding, usually the best "mod" you can do for any amplifier.