|
Post by merton on Dec 31, 2006 18:06:14 GMT
it does this even when i don't have my pc on. the only antenna i have is my wireless card.
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Dec 31, 2006 18:08:09 GMT
just for the hell of it have you tried using the amp in another room entirely connected to a portable player or other audio source ?
|
|
|
Post by merton on Dec 31, 2006 20:46:40 GMT
no... and i don't have another audio source.
and if it's not supposed to make that thock, and thoomp sounds in my phones when i turn it on and off, resectively, why does it do that?
here are pics.
.. they'll be posted if photobucket ever uploads them. :/
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Dec 31, 2006 20:58:44 GMT
first off it is damn near impossible to diagnose a problem online without at least some elimination of possibilites.How else to know what the "fix" is if I/We have nbo idea if the problem is amp related,power supply related or environment related ?
Any repair person down to the lowliest "I do this as a hooby" type knows you do the basic process of elimination to narrow down the causes or you may as well piss in the wind hoping you are upwind by pure dumb luck so you don't get wet in the process.
You need to narrow down the possible suspects at your end which at the minimum includes moving the amp to another location to see if the cause is environment,try another source,ANY source (portable CD player,MP3,player,radio,ANYTHING),swap out the interconnects for new ones to see if THAT is the problem (even the cheap ass cables that come with DVD players/CD players work for this or if none available $5 radio shack cables) and finally the powering device needs to be expcluded or identified as the problem.
this is a bit harder to do if you don't have the ability to make a battery power pack plug in but at the minimum again you need to move the wall wart to another outlet in another room to see if it is the shared outlet at fault (computer,amp/whatever else is on the sdame room circuit including flourescent lighting)
Once all the above EXTERNAL sources are either eliminated or identified then and only then can we know the problem is internal to the amp and at that time proceed with tracking down the "why" with again a process of elimination beginning all over again that goes from the amp input to the amp output as the possible cause.
This shit is mostly easy but only if we can eliminate "step 1"and move on to "step 2",etc...........
|
|
|
Post by merton on Dec 31, 2006 21:03:09 GMT
|
|
|
Post by merton on Dec 31, 2006 21:07:01 GMT
also... it makes the buzz even when i have the source attached and i'm in the bathroom with the doors closed.
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Dec 31, 2006 21:08:26 GMT
the only "possibles" I see internally are what looks from the pics to be sloppy soldering in some areas and may take a simple "reflow" to get the amp working.
Cold solder joints make a high resistance connection that can act more like a rectifier thus a classic "AM Radio Detector" than an amp and could be (if all else eliminated) the problem,one easily corrected if you have the skills with a soldering iron.
My best guess anyway.....................
|
|
|
Post by merton on Dec 31, 2006 21:18:11 GMT
that would just end up screwing crap up.... i've only soldered once... and it was a failure.
were you being serious about the thack and the thoomp being abnormal?
do you think this amp delivers enough current for my present phones? it has 4 1000uF caps.
i've been thinking... maybe i could trade you this amp for one made just for these phones (that warm sounding version of the ra1 with the meier cross feed)... but i would like it if you took the alps blue velvet pot off my amp and slapped it on the new one.
what do you think?
(and notice that it had the buzz even in another room with no source connected.)
|
|
|
Post by PinkFloyd on Dec 31, 2006 21:22:16 GMT
With the amp open and it switched on (CD player with disc playing set it to PAUSE) get yourself a piece of wire with both ends stripped. Hold one piece of the wire onto one of the screws on the back of your potentiometer (the volume control, the blue thing) and touch the other end of the wire onto the amp enclosure.... where the screws go in to fix the end panels would be a good place as these will be free of paint.
Try that first and let me know if the buzzing gets worse or disappears.
I'm not too sure about those two phono sockets attached directly to the metal enclosure without an insulating washer either.... maybe nothing but an area I've found can contribute to slight buzzing in certain amps. With that wire you can also touch one end on the screw at the back of the volco and the other end to one of the ground tags on the phono sockets (preferably to both of them) try that. The tags on the phono sockets with the green wire attached to them.....
|
|
|
Post by merton on Dec 31, 2006 21:29:44 GMT
wassa volco?
|
|
|
Post by merton on Dec 31, 2006 21:37:33 GMT
touching the wire to the case and the pot screw did nothing.
touching the wire from the post screw to the green wire tab on the rca did nothing.... made a little crackling sound when scraping the rca though.
i'm using a twist tie for this.... that should do the job... right?
both of those were tried with no source connected....
trying with source now.
still no effect
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Dec 31, 2006 21:46:08 GMT
if it is more than a mild thwump then the design is a piss poor one that is not only irritating but can if bad enough take out your headphones because it says to me there is DC on the output when turned on OR the caps are too big and need somethng to slow down the turn on capacitor charging. that is the "on" sound The off sound means there is no discharge path for the amp other than your headphone OR again there is a DC rider on the output. Both easily corrected with good technique but I will be damned if I re-engineer someone elses amp design to make it more user freindly without getting payed to do it since any corrections would be used and as usual without mentionng the source of the "fix" and those days are way over for me.If someone else wants to go for it cool,just not me anyone in your neighborhood a "fix it" type or electronics geek ? If so offer to buy them a six pack or toss them a tenty spot to reflow the solder joints for you.I am always suspicious of "gobbed" solder connections because they usually mean there was a problem with the flow and the person doing the assembly figured "hell,I'll fix it by adding more solder to it !" which does ZERO for the initial problem which in my experience is uaully a cold joint under the glob that now hidden impossible to "see" with the naked eye and damn near impossible to measure because the parts in the circuit itself will have an effect on the reading unless one end lifted out of circuit. Bad soldering technique is respnsible for 99% of electronic device problems with the other 1% usually a bad part or a part inserted wrong. plenty big enough,if anything too much if it is two banks of 1,00uF+1,000uF without any intervening resistor (CRC filter) and no device to slow down the turn on surge stay tuned on this one Merton.I am gathering a BOM (Bill Of Materials) to whip out a trio of "bloat free" op amp based headphone amps and they being small and light plus having a very low parts count will be dirt cheap to build so on the "all three shold be good but one the better of the three" theory will have to "strays" needing a good home with you at the top of the list.At that time you can either send me the volume pot or send me a new one and i will cram it in if you like you couls also disconnect that crossfeeed in your amp.send it to me and I will stik that puppy in too,maybe even if you are a good boy buffer the input for ya COOL ! A start man ! Now take a interconnect cable,insert one end into the amp inputs then take a wire and short the plugs (s) at the other end "hot" to "ground" so you properly load the intput for a valid test of buzzzies. ALL amps will be noisy with an output load but no input load
|
|
|
Post by PinkFloyd on Dec 31, 2006 21:50:41 GMT
The pictures are no too clear but from what I can see the soldering looks a bit iffy in places. As Rick says, tart this area up and it could solve the problem. Barring that, haven't got a clue there are so many things that could be causing a buzz and online diagnosis is impossible.
|
|
|
Post by merton on Dec 31, 2006 21:53:48 GMT
well.... since this is bad for my phones... did you mean plugging them in before i turn on the amp and taking them out before i turn off the amp would protect them?
and also... i was just going to send you the whole damn amp. i've no use for it if it's junk. i want the meier cross feed though... and to put the alps on the new amp. you can have all the other parts. i imagine they cost at least $100 new... the amp cost about $200 before all that shipping and repairing.
i'll try that thing out. it's just i don't want to damage my ety's and they're all i got.
|
|
|
Post by merton on Dec 31, 2006 22:00:25 GMT
i'm not quite sure what you meant on that last one...
i connected only the black rca... then i touched the wire from from the red tab on the red rca to the green tab on the red rca.... no effect.
|
|
|
Post by merton on Dec 31, 2006 22:07:58 GMT
and please make the one headed for me rather warm sounding.
what were you going to charge for one of them?
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Dec 31, 2006 22:23:04 GMT
may be OK for the 'phones,death for the amp depending on topology since many "DIY" type amps have totally unproteced outputs and some buffers also having no protection can go balls up from the dead short created by the headphone jack when plugging/unplugging the cans.One of those often overlooked areas where the "fix" either proper output protection resistive element,a headphone "mute" switch that works well even if simple (but only if you actually USE it) or a more complex instant "off" slow on output muting relay with the ulimate in complexity being a headphone "sense" relay activated by a switching jack. Would be asking a lot in a DIY product and would add to cost in a commercial product so why you see it rarely until you step up into a higher dollar amp class (pretty routine in el cheapo cell phone amps though,go figure ;D ) that would also work.I can then either modify/repair the original or gut it for parts to build you a new one,whichever makes for the cheapest solution that sounds good.would use my own lo-z cans for the testing stage don't blame you there man.I was just mentioning worst case "possibles" to always be considered when you have an amp with a high level THWUNP when cycled through the on/off stage ANOTHER "potetential" source of the problem eliminated and helps narrow down the "what". dirt cheap,as cheap as is possible and still have a usable amp.I don't do this for a living or even in any numbers except for freinds and family as gifts so more favor than any get righ quick scheme.Expect you will be surpised at the end cost
|
|
|
Post by PinkFloyd on Dec 31, 2006 23:03:31 GMT
If it's any help Rick I'll send you over some "pulls" along with the 'phones and CD's and definitely a couple of brand new top quality teflon insulated phono sockets for Merton's amp (I got a job lot of them) those el cheapo ones that are on the amp are just awful....... anything else you may need that you don't have to hand? Let me know.
|
|
|
Post by merton on Dec 31, 2006 23:03:50 GMT
so... where do i send this crap box i have?
and what is the difference between a high level thwump and a low level one?
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Dec 31, 2006 23:16:16 GMT
low level=there but not so loud it is more than a minor annoyance
high level=enough to startle and make a person wonder if they just did damage to either their headset or worse,their hearing
As to the other.send me an email and I will reply with the details.I don't do "personal information" online
|
|
|
Post by merton on Dec 31, 2006 23:26:34 GMT
yeah... i'd say the thump is in the 40-60 decibel range with these phones. it's not startling... it's not loud... it's not quiet either. it's probably a little bit quieter (10 decibels or so... hard to tell... maybe 20decibels quieter) than the music i play (at the normal volume i use)...
so safe or no? (sorry for the redundancy)
e-mail sent
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Dec 31, 2006 23:30:37 GMT
hard to tell by the description but my measure is if it is enough to be a point of concern the concern usually well founded even if purely on instinct and notr techncal reasons.We humans have an uncanny ability to KNOW when something is wrong even if we don't know the how and why of it
|
|
|
Post by merton on Dec 31, 2006 23:39:02 GMT
thanks to all of you.
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jan 1, 2007 0:28:13 GMT
have a happy New Year bud
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jan 8, 2007 2:47:38 GMT
Amp arrived safely though have not had a chance to look under her dress yet (Moms birthday yesterday,NFL playoffs today) but will as soon as I can and get back to you on the solution or if we should gut it and build a new amp in the same case BTW-will come back to you in a WAY smaller box dude
|
|