bluesboy Posted February 12, 2007 Share Posted February 12, 2007 I recently sold a Phase Linear 400 Power Amp in near mint condition on EBAY. It was such a pretty piece of equipment, I was really hesitant to sell it, but I just didin't have any use for it anymore. The following is an e-mail I got from the buyer today. "Dear Seller, I sent you an e-mail a while back that I was having problems getting this near mint condition amp. Well, I have spent a lot of my time tracking down fuses for the amp. What it was doing from day one is both needles were red lining to the right. I checked the fuses and the one in the center was blown. The two 5 amp fuses to the left were short and the right 8 amp was long, so I went looking all over trying to find short fuses and could not. I got the thought to look at one that I have and check the fuses which I never did before, and they were all long fuses. The fuse cartridges are all long. It just happened that yours had two short ones. I went out and purchased numerous fuses to try it out. This amp is a FUSE BLOWER and this was supposed to replace the one I have that does not work that I purchased last year on EBAY at considerably less priced than yours. I am not happy with this, not sure if something happened in shipping. I e-mailed other sellers for clues. What do you think?" Does anybody out there have any ideas as to what the problem might be? Quote Link to comment Share on other sites More sharing options...
Deang Posted February 12, 2007 Share Posted February 12, 2007 We used to call them Flame Linears. Sounds like you need a service manual so you can figure out the proper fuse values for the different positions. Quote Link to comment Share on other sites More sharing options...
bluesboy Posted February 12, 2007 Author Share Posted February 12, 2007 Thanks Dean I'll see if I can find a manual. What a pain in the you know what. I should of just kept the thing. We used to call them Flame Linears. Sounds like you need a service manual so you can figure out the proper fuse values for the different positions. Quote Link to comment Share on other sites More sharing options...
joessportster Posted February 12, 2007 Share Posted February 12, 2007 how long has the buyer had the amp, he says doesnt know if it was damaged in shipping, how did the box look? any damage? i had a deck dropped and the box looked fine but after opening the tape deck it was found a card was cracked and it could have only happened from a solid drop (guess the box landed, flat on a side and the jolt cracked a board) ups paid for the damage !!!!, i started with phase linear 400 amps, and they have a tendency for what i will call caps to go bad age thing, (not sure they are capss but they are located on the back of the amp between the cooling fins (may be under thin metal covers some have the covers some dont) look between the wider slots of the fins there are several of them back there) if the box was damaged i hope the buyer kept all the packing materials !!!!!!!!! Joe Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted February 12, 2007 Share Posted February 12, 2007 We used to call them Flame Linears. Sounds like you need a service manual so you can figure out the proper fuse values for the different positions. I always thought that the fuses were intended to be wrapped in tin foil by the user. No?[] tc Quote Link to comment Share on other sites More sharing options...
Guest " " Posted February 12, 2007 Share Posted February 12, 2007 The manual will be helpful.... One issue is impedance....he may be using speaker (s) with a combined impedance of less than the min recommended for the amp. Another issue could simply be frayed speaker wire on either end. And lastly....equipment over 10 uears old, which has not been in frequent use during recent times need to be brought up on a variac type device slowly for a period of time at progressive AC voltages until the caps have charged...then left on for a few hours...the longer the better....this helps reform the capacitors. Quote Link to comment Share on other sites More sharing options...
thebes Posted February 12, 2007 Share Posted February 12, 2007 It could be something really simple. He could be using fast blow fuses instead of slow-blow. Quote Link to comment Share on other sites More sharing options...
djk Posted February 12, 2007 Share Posted February 12, 2007 The only fuse that should be used in the Phase Linear 400 is the AGX 5A, a very fast acting type that is short. Quote Link to comment Share on other sites More sharing options...
bluesboy Posted February 13, 2007 Author Share Posted February 13, 2007 The only fuse that should be used in the Phase Linear 400 is the AGX 5A, a very fast acting type that is short.Thanks for the info . I'll pass it along. I wonder if the AGX 5A can be found at radio shack or if it's something that needs to be ordered from parts express or someplace like that. Quote Link to comment Share on other sites More sharing options...
djk Posted February 13, 2007 Share Posted February 13, 2007 DigiKey or Mouser have them, RS does not (in my experience). http://hometown.aol.com/phasetek2/pl14.jpg Quote Link to comment Share on other sites More sharing options...
russ69 Posted February 14, 2007 Share Posted February 14, 2007 I'm not sure if I understand what the buyers problem is. Back in the day, I remember my Phase 400 would redline the meters on power off but I don't remember if that happened all the time or only when it's not connected to the loudspeakers. At any rate it was normal thing. Thanx, Russ Quote Link to comment Share on other sites More sharing options...
khorn51 Posted February 14, 2007 Share Posted February 14, 2007 All my old Phase linear amps have 10 amp long fuses in them both 700's and the 400's . Back in the day I am told by the old PA techs this was a common mod but you had to run fans. The stock fuses would just blow to easy when the amps are really pushed . I also use two box fans mounted under the heat sinks to keep them cool. One last thing I use them in my vintage 70's PA for the real vintage rock pa sound. I would with any old Phse linear have it gone over just to be safe as they are old animals now but still cool looking. Quote Link to comment Share on other sites More sharing options...
djk Posted February 14, 2007 Share Posted February 14, 2007 "All my old Phase linear amps have 10 amp long fuses in them both 700's and the 400's ." You just should have used tin foil. "The stock fuses would just blow to easy when the amps are really pushed " Isn't it amazing how fast you can run out of power, even with a big amp? The amp with the short (correct fuses) is a fuse blower because they are the correct fuses and the amp is being overloaded. The new owner is welcome to use long fuses, as long as he remembers he now has no protection. When he runs into a real problem it will just blow up. If he has the right power line fuse in it it won't catch on fire (hopefuly). Quote Link to comment Share on other sites More sharing options...
bluesboy Posted February 14, 2007 Author Share Posted February 14, 2007 I'm not sure if I understand what the buyers problem is. Back in the day, I remember my Phase 400 would redline the meters on power off but I don't remember if that happened all the time or only when it's not connected to the loudspeakers. At any rate it was normal thing. Thanx, Russ Russ, The way I understand it the meters red line when the power is turned on. That's when the fuse blows. I turned it on to take pictures of it for the ebay add to show the VU meters lit up. Every thing looked fine. Quote Link to comment Share on other sites More sharing options...
bluesboy Posted February 14, 2007 Author Share Posted February 14, 2007 DigiKey or Mouser have them, RS does not (in my experience). http://hometown.aol.com/phasetek2/pl14.jpg Thanks for the schematic. I'll pass that along too. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted February 14, 2007 Share Posted February 14, 2007 "I turned it on to take pictures of it for the ebay add to show the VU meters lit up. Every thing looked fine." well since this turned into a fuse thread, and there is still a question of root cause.....you might want to have the new owner try to power up with out speakers, nothing connected to the inputs and standard fuses. If he is using speakers with to low of an impedance we don't want him putting in 100amp fuses.......do we? for all we know, he's using a surge protector to turn everything on with the flick of one switch.....a very popular way of destroying your equipment. also....before putting in the 100amp fuses.......maybe we should determine if the new owner has the skill sets or knows someone who can help him rig up some type of variac to bring up the unit slowly til the caps set. If now one he knows has a variac...he can use a 220 - 110 step down transformer which will provide 55 volts on normal 110 ac. if the root cause is not determined....and you put in 100amp fuses......your done gambling.....fireworks....no more amp. Quote Link to comment Share on other sites More sharing options...
bluesboy Posted February 14, 2007 Author Share Posted February 14, 2007 Speakerfritz, I used the only a couple of times in the last two years to test speakers in the shop. There was probably 7-8 months at least between uses. I always just plugged into the preamp, hooked up speakers and fired it up no problem. It never occurred to me that a SS amp would have to be brought up slowly. I thought that was something you had to do with a tube amp that hadn't been powered up for some time. But still you would think that if the problem was that the amp needed to be brought up to power slowly a fuse would have blown when I turned it on just before I shipped it. Anyway, thanks for the help. I appreciate your input. Don Quote Link to comment Share on other sites More sharing options...
Guest " " Posted February 14, 2007 Share Posted February 14, 2007 ' I thought that was something you had to do with a tube amp that hadn't been powered up for some time. " Amoung the experts....which excludes me...the rule is any electronic's over 10 years old, not used in 30 days. I slowly bring up all old gear not used in a while and never have any problems. Just wanted to bring up the root cause issue. Quote Link to comment Share on other sites More sharing options...
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