As I am a tube man, I bought the 212r Fender amp only to have enough headroom if there is no PA on stage. Finally I love the clean sound of this 212R by using my pedals. With no effect pedals it is already pretty nice for a solid state and sounds typically "Fender", just a bit colder and punchier than my tube amp. As soon as I use the pedals, the difference in sound to my tube amp is minor in my ears, but the 212R stays a lot longer clean when cranked up. My tube amp goes into distortion when I play it loud, which is an unwanted effect to me. I prefer to use the solid state to stay as clean as possible. That´s what I need it for. No distortion at all is what I call my own style. The 212R is not very reliable. Therefore I will replace some resistors and diodes by better ones as soon as the amp restarts to have issues. By the way: I love my tube amp. I ever preferred tube amps, but the maximum clean headroom that I want comes out of a solid state amp.
You're right R144 and R145 in Fender Frontman 212R are way bellow the amp's specs!! For those who still have this amp and have this reisitor overheating issue, i suggest replacing those two 330R 5W resistors with two 470R 25W ones (minimum, to a maximum of 820R 25W) and it should stop overheating like it does!! Hope this helps you, people!! ;)
Hi metal alex. I have the same overheating issue. I replaced blown capacitor C39 on the pre out section + R144 +R145 resistors and checked for desoldered joints(I found a few,2 on those resistors.On reassembly amp worked well for 30 mins,then started to crackle as the resistors warmed up and it started to smell with the heat! Power off. Any pics of how you mounted the bigger resistors (2 x 470R 25w) ?I have plenty of small (PC type ) heatsinks,which will probably do the job. Thanks for the info,so far
@@theweatherman1874 I drilled holes at the back of the amp's chassi, put some thermal paste on the base of the resistors (TimTronics grey ice) and fixed them to the chassi with two M2.5 screws and nuts for each resistor!! The aluminium chassi of the amp will get that heat dissipated more efficiently than the heatsinks, as you have that whole suface to serve as a heatsink for them!! :) Besides being and excelent electronic shielding conductor, aluminiun is also an excelent heat dissipation material!! Just get the resistors' template (you can draw it in a piece of paper, like i did) and make 4 holes with some 2,4 to 2,8mm diameter to fit the screws there, at the amp's back, inside the amp!! Then, all you need to do after you're done drilling those holes, place the screws with the head outside and tighten the nuts on the inside!! Don't forget to put thermal paste on the base of the resistors before!! ;) When you make the drill holes, i suggest that you start with 1,5 or 1,8mm drill bit and progressively get larger ones as you go!! Time consuming, but it gets a lot easier as you go!! i started with 1mm, 1,2mm, 1,5mm, 1,8mm, 2mm, 2,25mm, 2,4mm, 2,5mm and 2,6mm until the screws fit right through the holes!! :) The only thing you need to be careful with is your drilling machine's rotation so the drill doesn't go off the mark!!
You are a star ,my friend! Thanks for the detailed info you have provided,this amp has had limited use - 10 rehearsals and 3 gigs max.Instead of staring at a heap of junk, I can see this working again. I tried replacing the 5w 330 ohm resistors and it worked for a short time. Thanks for all the info.
About the R144 and R145 dimensioning, it is worth noting that this section of the power supply provides the Icc, the supply current, to the 8 opamps of the board and to a bunch of other parts, while providing the polarization current to the 16V zener diode. As an approximation, the R144 and R145 (whose nominal value on the schematic is 200 ohm thus providing 130 mA) should not be higher than 270 ohm for the supplied circuits to correctly operate. The 330 ohm value is a limit not to be exceeded, IMHO. So, the dissipated power cannot be traded for current because the overall 100 mA requirement (please consider that the RC4560 could drain up to 6 mA each). The only approach to an easier SOA for R144 and R145 is going for a 10 W rating, provided that the dissipation is 2.5W over 270 ohm or 3.4W over 200 ohm. Thus, 10W is an easy margin! About the zener diode dissipation, the worst case value is 1.25 W (with 330 ohm resistors) which is 1/4 of the "nominal" dissipation spec of the 1N5353B, despite it strongly depends on how the diode is mounted on the pcb, as a function of the cathode lead lenght and temperature.
@RonnyGuittar I'd suggest to use the resistor spec value of 200 ohm but with 10 W power rating (instead of 5W) for both R144 and R145. If you cannot find 200 ohm 10W resistors, you can parallel 2 x 400 ohm 5W resistors which also increases the reliability as if one of the parallel resistors fails, the other can keep the amp running (with some limitations though)
Hello, sorry to bother. I just got same one - working fine. but i notice only one speaker is engaged. do you know if the second one kicks in under curtain conditions, or my amp is malfunctioning? appreciated.
kryuga both speakers should be working. If you’re already getting sound out of one speaker, then it’s highly likely the amp is okay. I’d be testing the speaker that isn’t functioning, or check the wiring to that speaker.
I haven't watched it yet and I'm guessing it's the usual suspects, the 330 ohm 5W ceramic resistors. It's a common problem in all the amps that use this board
@@whatsstefon ya gotta love the pots too. Plastic craptastic. I picked up a Princeton 65 a couple weeks ago that had overheated one of the resistors and had a bad solder connection. The resistor was still in tolerance but I replaced them both and left the leads long. They're about a half inch off the board. The idea is to keep them from burning up the board and maybe get more air, and the long leads may help as a heat sink, probably not but wth. The holes they put under them on the board for convection cooling don't seem to help much.
Jacob Gardner it could be a number of things. It could be the switch itself is faulty, it could be as simple as giving the footswitch socket a clean as it might be dirty or dusty. It could be a fault in a solder joint or crack in the PCB. It could be a faulty relay.
It's difficult to say, but definitely try testing the AC ripple from the filter caps. Also, you could signal trace from the input to the output stage and help isolate where the hum is entering the signal path.
As I am a tube man, I bought the 212r Fender amp only to have enough headroom if there is no PA on stage. Finally I love the clean sound of this 212R by using my pedals. With no effect pedals it is already pretty nice for a solid state and sounds typically "Fender", just a bit colder and punchier than my tube amp. As soon as I use the pedals, the difference in sound to my tube amp is minor in my ears, but the 212R stays a lot longer clean when cranked up. My tube amp goes into distortion when I play it loud, which is an unwanted effect to me. I prefer to use the solid state to stay as clean as possible. That´s what I need it for. No distortion at all is what I call my own style. The 212R is not very reliable. Therefore I will replace some resistors and diodes by better ones as soon as the amp restarts to have issues. By the way: I love my tube amp. I ever preferred tube amps, but the maximum clean headroom that I want comes out of a solid state amp.
You're right R144 and R145 in Fender Frontman 212R are way bellow the amp's specs!! For those who still have this amp and have this reisitor overheating issue, i suggest replacing those two 330R 5W resistors with two 470R 25W ones (minimum, to a maximum of 820R 25W) and it should stop overheating like it does!! Hope this helps you, people!! ;)
Indeed. Very underrated wattage on these.
Hi metal alex. I have the same overheating issue. I replaced blown capacitor C39 on the pre out section + R144 +R145 resistors and checked for desoldered joints(I found a few,2 on those resistors.On reassembly amp worked well for 30 mins,then started to crackle as the resistors warmed up and it started to smell with the heat! Power off. Any pics of how you mounted the bigger resistors (2 x 470R 25w) ?I have plenty of small (PC type ) heatsinks,which will probably do the job. Thanks for the info,so far
@@theweatherman1874 I drilled holes at the back of the amp's chassi, put some thermal paste on the base of the resistors (TimTronics grey ice) and fixed them to the chassi with two M2.5 screws and nuts for each resistor!! The aluminium chassi of the amp will get that heat dissipated more efficiently than the heatsinks, as you have that whole suface to serve as a heatsink for them!! :) Besides being and excelent electronic shielding conductor, aluminiun is also an excelent heat dissipation material!! Just get the resistors' template (you can draw it in a piece of paper, like i did) and make 4 holes with some 2,4 to 2,8mm diameter to fit the screws there, at the amp's back, inside the amp!! Then, all you need to do after you're done drilling those holes, place the screws with the head outside and tighten the nuts on the inside!! Don't forget to put thermal paste on the base of the resistors before!! ;) When you make the drill holes, i suggest that you start with 1,5 or 1,8mm drill bit and progressively get larger ones as you go!! Time consuming, but it gets a lot easier as you go!! i started with 1mm, 1,2mm, 1,5mm, 1,8mm, 2mm, 2,25mm, 2,4mm, 2,5mm and 2,6mm until the screws fit right through the holes!! :) The only thing you need to be careful with is your drilling machine's rotation so the drill doesn't go off the mark!!
You are a star ,my friend! Thanks for the detailed info you have provided,this amp has had limited use - 10 rehearsals and 3 gigs max.Instead of staring at a heap of junk, I can see this working again. I tried replacing the 5w 330 ohm resistors and it worked for a short time. Thanks for all the info.
@@Wohlfheimehr Brilliant,cheers Alex
About the R144 and R145 dimensioning, it is worth noting that this section of the power supply provides the Icc, the supply current, to the 8 opamps of the board and to a bunch of other parts, while providing the polarization current to the 16V zener diode. As an approximation, the R144 and R145 (whose nominal value on the schematic is 200 ohm thus providing 130 mA) should not be higher than 270 ohm for the supplied circuits to correctly operate. The 330 ohm value is a limit not to be exceeded, IMHO. So, the dissipated power cannot be traded for current because the overall 100 mA requirement (please consider that the RC4560 could drain up to 6 mA each). The only approach to an easier SOA for R144 and R145 is going for a 10 W rating, provided that the dissipation is 2.5W over 270 ohm or 3.4W over 200 ohm. Thus, 10W is an easy margin!
About the zener diode dissipation, the worst case value is 1.25 W (with 330 ohm resistors) which is 1/4 of the "nominal" dissipation spec of the 1N5353B, despite it strongly depends on how the diode is mounted on the pcb, as a function of the cathode lead lenght and temperature.
Absolutely agree. Thank you for the explanation and expertise.
So what should I finally put on to the board to make my 212R work constantly reliable ?
@RonnyGuittar I'd suggest to use the resistor spec value of 200 ohm but with 10 W power rating (instead of 5W) for both R144 and R145.
If you cannot find 200 ohm 10W resistors, you can parallel 2 x 400 ohm 5W resistors which also increases the reliability as if one of the parallel resistors fails, the other can keep the amp running (with some limitations though)
Hello, sorry to bother. I just got same one - working fine. but i notice only one speaker is engaged. do you know if the second one kicks in under curtain conditions, or my amp is malfunctioning? appreciated.
kryuga both speakers should be working.
If you’re already getting sound out of one speaker, then it’s highly likely the amp is okay.
I’d be testing the speaker that isn’t functioning, or check the wiring to that speaker.
@@whatsstefon thanks a lot..i did some cleanings. now one speaker is louder than the other )))) but both work...
kryuga that’s good news. Perhaps it was just a loose or dirty speaker terminal connection.
Damn, 3 years later and i ve got one stripped on my desktop. Thanks for all the tips here.
Btw what did u end up doing with the amp and cabinet?
I ended up fixing it up and selling it. The customer still uses it daily.
If I replace the 5w resistors with 10W
Do I have to change anything else to compensate.
No. All this does is give you more heat handling capabilities.
I haven't watched it yet and I'm guessing it's the usual suspects, the 330 ohm 5W ceramic resistors. It's a common problem in all the amps that use this board
Indeed. And that’s just to begin with.
Cheers for your comment. Always appreciated!!
@@whatsstefon ya gotta love the pots too. Plastic craptastic.
I picked up a Princeton 65 a couple weeks ago that had overheated one of the resistors and had a bad solder connection. The resistor was still in tolerance but I replaced them both and left the leads long. They're about a half inch off the board. The idea is to keep them from burning up the board and maybe get more air, and the long leads may help as a heat sink, probably not but wth. The holes they put under them on the board for convection cooling don't seem to help much.
@@deaddiver3768 yeah. Definitely worth placing them a small distance away from the board for additional cooling.
Yeah. Plastic pots. Yuck.
I have on of these amps and the channell selector switch isnt working
Jacob Gardner it could be a number of things. It could be the switch itself is faulty, it could be as simple as giving the footswitch socket a clean as it might be dirty or dusty. It could be a fault in a solder joint or crack in the PCB. It could be a faulty relay.
@@whatsstefon thanks man i may try to look at it myself but its prolly out of my league
Hello sir, I've got frontman 212r hum about -14 db at 199 hz and it's annoying :/ would you give a clue what should I replace/do to fix this, thanks.
It's difficult to say, but definitely try testing the AC ripple from the filter caps.
Also, you could signal trace from the input to the output stage and help isolate where the hum is entering the signal path.
@@whatsstefon I'll check it, thanks
make a cab
SearingCustomGuitars I ended up selling it. Going to buy some pine and make a naked finger joined cab.