Hi all,
I'm new here to the forums so I hope this is going in the right place. If not, well oops. Anyways, I recently bought an old HK Citation 12 off of the bay that is, believe it or not, in very good condition considering it's age and the fact that it was assembled from a kit, and not at the factory (yes I checked all the connections and they are sound). However, it has one problem. When it's getting power, the amp clicks, pops, and occasionally thumps. What I mean by that is that the clicks and pops remind me of what you would get off of an LP and the occasional thumps are much akin to that of a turn on thump, but this is all while the amp is playing also while it doesn't have power. Because the thing doesn't have a power switch, I have to unplug it until I can jerry rig something, but the amp still pops and clicks, even without power! Because of this, the only assumption I can come to is that the power supply caps have gone bad, but I'm not sure. Any help is greatly appreciated! Thank you very much and sorry about the lengthy post!
Paco
I'm new here to the forums so I hope this is going in the right place. If not, well oops. Anyways, I recently bought an old HK Citation 12 off of the bay that is, believe it or not, in very good condition considering it's age and the fact that it was assembled from a kit, and not at the factory (yes I checked all the connections and they are sound). However, it has one problem. When it's getting power, the amp clicks, pops, and occasionally thumps. What I mean by that is that the clicks and pops remind me of what you would get off of an LP and the occasional thumps are much akin to that of a turn on thump, but this is all while the amp is playing also while it doesn't have power. Because the thing doesn't have a power switch, I have to unplug it until I can jerry rig something, but the amp still pops and clicks, even without power! Because of this, the only assumption I can come to is that the power supply caps have gone bad, but I'm not sure. Any help is greatly appreciated! Thank you very much and sorry about the lengthy post!
Paco
Hi Paco. You might want to ask over in the Pass section. The Citation 12 is one Nelson Pass's older constructions. Do a search in the Pass section too, there are some threads about the Citation 12.
http://www.diyaudio.com/forums/showthread.php?threadid=28402&highlight=
http://www.diyaudio.com/forums/showthread.php?threadid=28402&highlight=
Actually, I was doing some research and came across a page talking about modding a Citation 12 with "ultra linear transistors", but that's besides the point. What it mentioned are some of the problems with the Citation 12s, more specifically this, "a problem in which the proprietary six-lead dual input transistors would develop loud, random, spike pulse noises, which would drive the amplifier to full output, or to blown outputs, often taking out the attached speakers' tweeters." Unfortunately, I don't yet know enough about amps to know if this is what's going on. Here's the page. http://slbender.exactpages.com/citation.html It details a number of problems, but I couldn't begin to tell which I'm dealing with. Honestly, any kind of clue as to what the problem may be is greatly appreciated. Thanks!
well ......
this is one amplifier that extensivly has been talked all over in the forum ..... you will find many threads including infos about specs performance trouble and variations .....
expecting any fast food solution it will never come from any forum member about the specific problem
in general ......
unit like that aged that much will need a total recaping and this is not a sugestion it is simply a fact ....
then also due to that age they might be many things that could create complications like soldering bad contacts cleaning and so on
if you like to play with it and you have enough skills you may wana look at the above link that explains a lot but requires an ammount of skills to proceed in repairs or upgrades
http://www.diyaudio.com/forums/showthread.php?s=&threadid=136261&highlight=
finally i would never spend time and money in the amplifier circuits included in this box .....unless you are the type of person that like to keep things as made
if not my recomendation will be to remove all the guts of this amp keep the rest and install inside more modern boards ..... that will outperform the original circuits for breakfast
best regrads sakis
this is one amplifier that extensivly has been talked all over in the forum ..... you will find many threads including infos about specs performance trouble and variations .....
expecting any fast food solution it will never come from any forum member about the specific problem
in general ......
unit like that aged that much will need a total recaping and this is not a sugestion it is simply a fact ....
then also due to that age they might be many things that could create complications like soldering bad contacts cleaning and so on
if you like to play with it and you have enough skills you may wana look at the above link that explains a lot but requires an ammount of skills to proceed in repairs or upgrades
http://www.diyaudio.com/forums/showthread.php?s=&threadid=136261&highlight=
finally i would never spend time and money in the amplifier circuits included in this box .....unless you are the type of person that like to keep things as made
if not my recomendation will be to remove all the guts of this amp keep the rest and install inside more modern boards ..... that will outperform the original circuits for breakfast
best regrads sakis
Yeah, I was thinking of just replacing everything that I can and keeping the original PCBs for convenience's sake, especially since I have no idea how I would track down replacements. Replacing that caps and anything else (resistors too? Maybe?) sounds like a fun project, something I was looking into doing anyways. My only worry would be about finding replacement transistors if need be...thanks!
Hi Paco,
I completely agree with Nelson. Adding that current source will help with more than just reducing the "pop" (bang?). The use of a relay delay for the speakers would eliminate this problem. I would do both.
I'd like to add that the "proprietary six-lead dual input transistors" are simply a dual transistor and may be replaced by a pair of matched singles. Many amplifiers did use a dual transistor, so it's not all that strange a part. Most Japanese amplifiers used a 5 lead device. Same thing with a common lead for the two emitters.
Anyway, some of the early ones did have a habit of going noisy.
-Chris
I completely agree with Nelson. Adding that current source will help with more than just reducing the "pop" (bang?). The use of a relay delay for the speakers would eliminate this problem. I would do both.
I'd like to add that the "proprietary six-lead dual input transistors" are simply a dual transistor and may be replaced by a pair of matched singles. Many amplifiers did use a dual transistor, so it's not all that strange a part. Most Japanese amplifiers used a 5 lead device. Same thing with a common lead for the two emitters.
Anyway, some of the early ones did have a habit of going noisy.
-Chris
Hi Nelson,
But, I was responding to Paco's original post.
I've been re-reading your papers lately Nelson. Good stuff, well written and amusing. Your approach to explaining things comes from a direction I haven't seen before. probably would have been easier for me to learn this way but they were not published in the early 70's. I'm reading your home brew op amp paper right now.
It's worth while to go back and revisit things you already know to fill in the gaps. Besides, inspiration for new ideas can be found in older material.
Thank you for making that material available to us on your web site.
-Chris
...and probably lower noise, by approx. 0.7071 as you now have but one device.
But, I was responding to Paco's original post.
I've been re-reading your papers lately Nelson. Good stuff, well written and amusing. Your approach to explaining things comes from a direction I haven't seen before. probably would have been easier for me to learn this way but they were not published in the early 70's. I'm reading your home brew op amp paper right now.
It's worth while to go back and revisit things you already know to fill in the gaps. Besides, inspiration for new ideas can be found in older material.
Thank you for making that material available to us on your web site.
-Chris
Thanks for the responses everyone!
I did a little more checking on the amp and found that the pops and what not are only coming from the right channel. And when I mentioned a thump, I didn't mean the normal turn-on thump, but that it does that well after having turned on...
I must also admit, that much of the terminology associated with amplifiers is, for the time being, well over my head, so I apologize for not understanding all of this the first time
I can check all the connections and see if that does anything; that's easy enough to do, but as far as adding a current source and what not, I must be honest, I have no idea what you're talking about :$
I did a little more checking on the amp and found that the pops and what not are only coming from the right channel. And when I mentioned a thump, I didn't mean the normal turn-on thump, but that it does that well after having turned on...
I must also admit, that much of the terminology associated with amplifiers is, for the time being, well over my head, so I apologize for not understanding all of this the first time
I can check all the connections and see if that does anything; that's easy enough to do, but as far as adding a current source and what not, I must be honest, I have no idea what you're talking about :$
Hi Paco,
If you don't really understand these terms, or how the amp works, you had better put off trying to fix it. Either that or get it to a professional. Well meaning friends aren't much better BTW.
You might have more success building a kit. That's easier than repairing something you don't understand.
-Chris
If you don't really understand these terms, or how the amp works, you had better put off trying to fix it. Either that or get it to a professional. Well meaning friends aren't much better BTW.
You might have more success building a kit. That's easier than repairing something you don't understand.
-Chris
That's reasonable, but honestly, if I blow it up and make the magic smoke come out, it won't be too big of a deal, it's just an amp. That is unless someone out there speaks up and tells me it's extremely valuable, in which case, fine, I'll have someone else fix it, but until then, no dice. I hope you understand, I'm not trying to be rude of pick a fight, honest, I'm just trying to make myself a little more clear about this, which is difficult to do through text only...
But the way I see it is that rather than give in and spend way more than I paid for it for someone else to fix it, I would prefer to see what I can do myself and just hope people don't get too mad at me for asking so many questions
But the way I see it is that rather than give in and spend way more than I paid for it for someone else to fix it, I would prefer to see what I can do myself and just hope people don't get too mad at me for asking so many questions
Hi Paco,
Okay, but my point is that right now your chances are slim. You need to know more to have a reasonable chance.
Now, if you can practice soldering with some kits or old junk stereos, that will help. If you can build a simple amplifier, some of those concepts will sink in easier.
You see, the sad thing is this. If you manage to fix it, you probably will not learn much. If you fail to repair it and possibly cause much damage, you still will not have learned anything about what went wrong. It's a lose-lose right now, probably ending badly.
Citation amplifiers tend to have a market value. They will sell for more than your average amp. It makes sense to properly restore this classic amplifier. I don't particularly love these, but there is no reason to take more chances than is reasonable with it. Then, if you get it done, you can hear what one sounds like and have some bragging rights.
That is my point. Trying to do something before you are capable is a waste. I would prefer that you get some knowledge on cheaper amps before attempting this one.
Have you even checked the value of this amp on the web? I just saw an ad for one. Working $499 USD. That seems to be worth fixing right, no matter who does the job.
-Chris
Okay, but my point is that right now your chances are slim. You need to know more to have a reasonable chance.
Now, if you can practice soldering with some kits or old junk stereos, that will help. If you can build a simple amplifier, some of those concepts will sink in easier.
You see, the sad thing is this. If you manage to fix it, you probably will not learn much. If you fail to repair it and possibly cause much damage, you still will not have learned anything about what went wrong. It's a lose-lose right now, probably ending badly.
Citation amplifiers tend to have a market value. They will sell for more than your average amp. It makes sense to properly restore this classic amplifier. I don't particularly love these, but there is no reason to take more chances than is reasonable with it. Then, if you get it done, you can hear what one sounds like and have some bragging rights.
That is my point. Trying to do something before you are capable is a waste. I would prefer that you get some knowledge on cheaper amps before attempting this one.
Have you even checked the value of this amp on the web? I just saw an ad for one. Working $499 USD. That seems to be worth fixing right, no matter who does the job.
-Chris
I really do appreciate your input and understand what you are saying. A far as replacing parts/soldering etc. etc., that is not at all a problem. I can do that very well, but what I'm looking for here is help on how to locate faulty parts, and that's basically it... or so I think.
I don't know, maybe I'm missing something here, but really and truly, I never had any intentions of having to do anything with that blasted amp but plug it in and enjoy it. However, it turns out I do, and so it shall be that way.
I don't know, maybe I'm missing something here, but really and truly, I never had any intentions of having to do anything with that blasted amp but plug it in and enjoy it. However, it turns out I do, and so it shall be that way.
Hi Paco,
No offense, but I don't think anyone has the time to train you to be a technician.
I don't mind helping people out, in fact I enjoy it. But the truth is simple. I get paid to service product, and troubleshooting via posts or email takes far longer than just doing it myself, on my bench. The same goes for other members here. I can't guide you for the simple reason that you can't be pointed in the right direction and know what to do from then on. You don't even have the ability to test parts properly, or the equipment required to test.
I don't want you to get hurt. I don't want you to ruin a nice amplifier that someone else with more skill could rebuild. My personal belief is that you would be further ahead selling that one and buying another that does work. To hold onto this and attempt to work on it without the skill to do so is fairly selfish as far as I can see. I have no problem with the concept of you attempting to service a lower powered amplifier that isn't worth as much. The chances of success would be a little higher, and the cost of failure is a lot less.
Anyway, I certainly don't want to annoy you. What you want to do is not realistic.
Think of this another way. If being a technician was so easy, why would it take years of education and more years of practice in the field? Think about this. You want to do right now what it takes most people years to learn about.
-Chris
No offense, but I don't think anyone has the time to train you to be a technician.
I don't mind helping people out, in fact I enjoy it. But the truth is simple. I get paid to service product, and troubleshooting via posts or email takes far longer than just doing it myself, on my bench. The same goes for other members here. I can't guide you for the simple reason that you can't be pointed in the right direction and know what to do from then on. You don't even have the ability to test parts properly, or the equipment required to test.
I don't want you to get hurt. I don't want you to ruin a nice amplifier that someone else with more skill could rebuild. My personal belief is that you would be further ahead selling that one and buying another that does work. To hold onto this and attempt to work on it without the skill to do so is fairly selfish as far as I can see. I have no problem with the concept of you attempting to service a lower powered amplifier that isn't worth as much. The chances of success would be a little higher, and the cost of failure is a lot less.
Anyway, I certainly don't want to annoy you. What you want to do is not realistic.
Think of this another way. If being a technician was so easy, why would it take years of education and more years of practice in the field? Think about this. You want to do right now what it takes most people years to learn about.
-Chris
Its not rocket science anatech, I would say dive in Paco, Whats more, with the citation being of some intrinsic value, Your more prone to watch exactly what you do!!! My suggestion is to research as much as you can on the web, Or here, Find out everything about your amp... Be prepared for setbacks and faliures.. its old, with tired components, expect wasting many, many hours, heartache..Pain..., But its fun.....Sometimes spending eight hours soldering seemingly endless amounts of resistors when a clean sweep is the order of the day, waking up with visions of melting solder on a pcb board gets too much....
I concur that offering advice is usually a shot in the dark..Because realistically anything is everything, Nothing could be something,
Funny thing is.the problematic scource is usually the last thing to be eliminated, Things get hot, hysteresis occurs!
Treat it like a jig saw puzzle, but be systematic in your approach!
Knock yerself out!
I concur that offering advice is usually a shot in the dark..Because realistically anything is everything, Nothing could be something,
Funny thing is.the problematic scource is usually the last thing to be eliminated, Things get hot, hysteresis occurs!
Treat it like a jig saw puzzle, but be systematic in your approach!
Knock yerself out!
I'm sorry, but I really dont agree. Messing around inside a power amp when you have little or no experience is not the way to begin in this hobby. You will end up with expensive damage, and possibly serious personal injury.
I still remember building my first mains power supply when I was 12. The schematic showed only a single secondary and full wave, I had a centre tapped transformer with two red wires and a centre black. I tied the two reds together - it worked, but the transformer got very hot, and eventually went off with a loud bang. Needless to say, I now triple check all such things.
I still remember building my first mains power supply when I was 12. The schematic showed only a single secondary and full wave, I had a centre tapped transformer with two red wires and a centre black. I tied the two reds together - it worked, but the transformer got very hot, and eventually went off with a loud bang. Needless to say, I now triple check all such things.
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