Best Regards,
Gary
(modrock)
Servicing Fender Concert 60 watt amplifier head
Moderator: jingle_jangle
Re: Servicing Fender Concert 60 watt amplifier head
Thanks very much Greg and all the others who have contributed to this discussion. I found a good honest local amp technician and he and I are going to decide what to do with the Concert head. Yes Greg, I think the concert head does sound better through a Marshall Celestion cabinet, but there will be an AC-30 in my future !
Best Regards,
Gary
(modrock)
Best Regards,
Gary
(modrock)
-
soundmasterg
- RRF Consultant
- Posts: 1921
- Joined: Tue Oct 01, 2002 1:06 pm
Re: Servicing Fender Concert 60 watt amplifier head
Glad to help!
The JJ's are decent tubes and Bob at Eurotubes is top notch, though many of the JJ selection has had quality issues recently. Tubes are built in batches, so it could be that they have had some bad batches perhaps. I listed the tube choices in no order of preference so don't let where they are in the listing influence you.
Greg
The JJ's are decent tubes and Bob at Eurotubes is top notch, though many of the JJ selection has had quality issues recently. Tubes are built in batches, so it could be that they have had some bad batches perhaps. I listed the tube choices in no order of preference so don't let where they are in the listing influence you.
Greg
-
BlueAngel
Re: Servicing Fender Concert 60 watt amplifier head
Not much to add to the info above, but since I was working on a Twin Reverb II today (the Concert's bigger brother) I would say...
The stock speakers are a definite weak link tonally and sometimes reliability-wise. I totally agree that these amps sound much better, especially on the overdrive channel, through just about any other speaker and definitely a Celestion. I've had great results with either a G12-65 (lower sensitivity, warm sound quite like a G12M-25 Greenback) or a G12-80/Classic Lead (higher sensitivity, bold sound quite like a G12H-30). The V30 is good too but will detract a bit from the clean tone.
If the amp has its original tubes - preamp or power - do NOT change them just because the amp 'needs servicing'. ONLY change them if they are definitely faulty, and don't think that they must be just because they're old. The quality of the GE preamp and Philips/Sylvania power tubes Fender used in the early 80s has never been even close to equalled by any modern tube, and they can last decades, preamps especially. Not only do they sound better and last far longer, you will get more measurable power with these power tubes than any modern type, even when they're quite old - the Concert really is a 60W amp with the original tubes, although you will be lucky to get close to that with anything else.
There is one known reliability problem that occurs fairly often - on the tag strip next to the power transformer there is a 47-ohm, 1/2W carbon resistor that supplies the power tube bias and low-voltage switching circuits. If this resistor burns out - which they do because they are run a bit too close to 1/2 a watt inside a hot amp for safety - you will lose the power tube bias completely and fry them. You will usually find this resistor has been replaced already, or if the amp hasn't been used much, original but discolored with heat. Replace this resistor with a 1W metal-oxide or wirewound 47 ohm, even if it has already been replaced with another 1/2W type and/or shows no sign of damage - it doesn't affect anything other than the reliability and is a sensible precaution.
The stock speakers are a definite weak link tonally and sometimes reliability-wise. I totally agree that these amps sound much better, especially on the overdrive channel, through just about any other speaker and definitely a Celestion. I've had great results with either a G12-65 (lower sensitivity, warm sound quite like a G12M-25 Greenback) or a G12-80/Classic Lead (higher sensitivity, bold sound quite like a G12H-30). The V30 is good too but will detract a bit from the clean tone.
If the amp has its original tubes - preamp or power - do NOT change them just because the amp 'needs servicing'. ONLY change them if they are definitely faulty, and don't think that they must be just because they're old. The quality of the GE preamp and Philips/Sylvania power tubes Fender used in the early 80s has never been even close to equalled by any modern tube, and they can last decades, preamps especially. Not only do they sound better and last far longer, you will get more measurable power with these power tubes than any modern type, even when they're quite old - the Concert really is a 60W amp with the original tubes, although you will be lucky to get close to that with anything else.
There is one known reliability problem that occurs fairly often - on the tag strip next to the power transformer there is a 47-ohm, 1/2W carbon resistor that supplies the power tube bias and low-voltage switching circuits. If this resistor burns out - which they do because they are run a bit too close to 1/2 a watt inside a hot amp for safety - you will lose the power tube bias completely and fry them. You will usually find this resistor has been replaced already, or if the amp hasn't been used much, original but discolored with heat. Replace this resistor with a 1W metal-oxide or wirewound 47 ohm, even if it has already been replaced with another 1/2W type and/or shows no sign of damage - it doesn't affect anything other than the reliability and is a sensible precaution.