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Lab Gruppen FP14000 clone amplifiers - Page 112

post #3331 of 4387
Quote:
Originally Posted by cubalis2 View Post

I also have a QSC amp that does back to front, so I was slightly confused with the fan direction.

Now that my cooling is sorted, my amp started power cycling this morning. It seems to do it randomly, with or without any load.

What points do I take the voltage measurement from to try and adjust the pots?

PM reply sent.

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post #3332 of 4387
Once I opened it up again it was obvious where the points were. Thanks!

Now the fun begins trying to get the very touchy pot to the right spot... I seem to have it stable at 195v, it was reading 198.4 and up before, does this seem good or should I shoot for lower?
post #3333 of 4387
If you can keep it at 195V then give it a shot. I was able to keep mine stable for a few weeks when it was around 190V or so before it started power cycling again. I had to lower it to around the mid 170s since there was no inbetween on my POT. It's been stable since. I'm guessing that since it's so touchy that the vibrations from mounting it back into the rack + all the vibrations caused by the subs knocked it back out of spec.
post #3334 of 4387
Quote:
Originally Posted by duc135 View Post

If you can keep it at 195V then give it a shot. I was able to keep mine stable for a few weeks when it was around 190V or so before it started power cycling again. I had to lower it to around the mid 170s since there was no inbetween on my POT. It's been stable since. I'm guessing that since it's so touchy that the vibrations from mounting it back into the rack + all the vibrations caused by the subs knocked it back out of spec.


Well it looks like my amp is in trouble. After fiddling with it yesterday I thought I had it stable, but it would cycle with any kind of decent load. On a whim I tried adjusting the pot back to full clockwise, and to my surprise it held there... all day. I used it for hours, most of the day and evening without any trouble. Full power and no complaints.

Tried it again this morning and it cycles randomly again. Lowering the pot back into the 190v range keeps it going, but it does not like any kind of load. I am guessing much like others the power board is at fault.

I have tried different power outlets, 20amp and 15amp, to no avail. frown.gif

Any other suggestions before I try to get Johnson/Sanway to help? I feel it may be difficult as it was a second hand unit from MK. Not his fault in any way, it worked great for the last 4 months! It only started acting up after I switched the fans around the other day. I will go back in and look for any shorted wires or other suspect connections.
post #3335 of 4387
The clue is since you changed the fans that the unit as been acting up.
I would check everything you may have touched or moved!
Maybe a bad solder of a cable may have made it worse.
Good idea to go in there and check all connections especially all the cables that were moved around for a loose connection or something


Good luck
post #3336 of 4387
Quote:
Originally Posted by cubalis2 View Post

Any other suggestions before I try to get Johnson/Sanway to help? I feel it may be difficult as it was a second hand unit from MK. Not his fault in any way, it worked great for the last 4 months! It only started acting up after I switched the fans around the other day. I will go back in and look for any shorted wires or other suspect connections.

Do you have a FP14k or a FP10000Q?
post #3337 of 4387
Quote:
Originally Posted by Jason kiDD View Post

Do you have a FP14k or a FP10000Q?
14k

Quote:
Originally Posted by Freniata View Post

The clue is since you changed the fans that the unit as been acting up.
I would check everything you may have touched or moved!
Maybe a bad solder of a cable may have made it worse.
Good idea to go in there and check all connections especially all the cables that were moved around for a loose connection or something


Good luck

Thanks!

I would like to think it's not a coincidence that it started misbehaving after turning the fans around. hopefully it is something simple/dumb like a loose fan cable or solder joint that I happened to wiggle.
post #3338 of 4387
Thread Starter 
might also want to try shaking any loose solder debris out or hitting it with some compressed air.
post #3339 of 4387
Quote:
Originally Posted by LTD02 View Post

consumer gear and pro gear work on different signal levels, but there is some overlap.

Sorta beating a dead horse here, but actually that's not where the "consumer" and "pro" levels come into play (with respect to pre out / amp input sensitivity). I averaged the input sensitivity of all my pro amps and of all my consumer amps and the pro amps actually came in with a slightly higher input sensitivity (require less signal) than my consumer amps. Pro vs. consumer level is with generally with regard to fixed level connections like tape in/out, again, not variable levels like pre out and amp input.

That said, pro amps typically do have lower input impedance than consumer amps and that could present an unfavorable load if the "consumer" pre out it's connected to is somewhat wimpy, inasmuch as having (relativley) high output impedance.
post #3340 of 4387
Forgive me if this was posted somewhere but is there a table where I could get the estimated output power of the FP14000 by the lights on the front that display signal level?

So If I'm peaking at -4db is that 2000W peak? 4000W peak per channel at X ohms?

Or if it is in voltage then that is fine. if 0db = 180V, what would -4 be? or what would -10 be?

Let me know my question makes sense.
post #3341 of 4387
Quote:
Originally Posted by whoaru99 View Post

Sorta beating a dead horse here, but actually that's not where the "consumer" and "pro" levels come into play (with respect to pre out / amp input sensitivity). I averaged the input sensitivity of all my pro amps and of all my consumer amps and the pro amps actually came in with a slightly higher input sensitivity (require less signal) than my consumer amps. Pro vs. consumer level is with generally with regard to fixed level connections like tape in/out, again, not variable levels like pre out and amp input.

That said, pro amps typically do have lower input impedance than consumer amps and that could present an unfavorable load if the "consumer" pre out it's connected to is somewhat wimpy, inasmuch as having (relativley) high output impedance.

thanks for the posts!! i acutally have no clue what the rca line out voltage or the output impedance is for my tuner. it is a technics sa-ex700 i think (its not here its in storage) with BOTH rca sub out and powered out for speakers. i have had it for nearly 15 years.
post #3342 of 4387
Quote:
Originally Posted by javi404 View Post

Forgive me if this was posted somewhere but is there a table where I could get the estimated output power of the FP14000 by the lights on the front that display signal level?

So If I'm peaking at -4db is that 2000W peak? 4000W peak per channel at X ohms?

Or if it is in voltage then that is fine. if 0db = 180V, what would -4 be? or what would -10 be?

Let me know my question makes sense.

http://www.crownaudio.com/db-power.htm. Put in any two (hit the reset button before starting or changing any numbers).

For example, if the amp is rated (or known to be) 7000W put that in Power A, then your -4dB change in the dB field, then hit calculate to get the resut in Power B (result roughly 2800W in this example).
post #3343 of 4387
Well, I'm officially at a loss of what to try next. I have searched it over for sketchy soldering, loose cables, shaken and blown air everywhere, etc and found nothing out of the ordinary. I made sure everything I touched the other day (ie. fans and wires) were not shorting.

Three days in a row, I turn it on in the a.m. and it does this behavior of cycling the power. Sometimes it starts instantly, sometimes it takes 5-15 minutes to start. Three days in a row I have fiddled with it, adjusted the voltage pot to no avail, and it remains the same. The strange thing is though, the last two days it eventually worked again, flawlessly. Today it has not worked for longer than 15 minutes.

Here is a vid of it doing its thing...


direct link as the vid doesn't want to work for me: here


It seems to me to be a short, but I really don't know why it is so sporadic.

Some info in case anyone trying to help wants it -

FP14k 120V
20amp dedicated (have tried other outlets - same behaviour)
no load
It was working great for ~4 months, and longer before that at MK's place
I switched the fan direction and it started.

One last thing to note, every now and then it will trip the wall outlet GFCI switch while cycling.

Any other ideas of what to look for? Would it be a bad power board if it does eventually work?

Thanks to everyone who has given suggestions thus far. The search continues...
Edited by cubalis2 - 9/18/13 at 11:41am
post #3344 of 4387
LOL as a gimmick i would put the fans back the way they were..
post #3345 of 4387
Thread Starter 
Try it on a different circuit. Measure the voltage on your circuit also. It's odd that it fails in the AM but not later?
post #3346 of 4387
Quote:
Originally Posted by javi404 View Post

Forgive me if this was posted somewhere but is there a table where I could get the estimated output power of the FP14000 by the lights on the front that display signal level?

So If I'm peaking at -4db is that 2000W peak? 4000W peak per channel at X ohms?

Or if it is in voltage then that is fine. if 0db = 180V, what would -4 be? or what would -10 be?

Let me know my question makes sense.
I have no idea what the copy units display-but the REAL Lab Gruppens meters are tied to the max output voltage selection on the rear pane.

As you change the max output voltage-the meters will also change (assuming the drive level has stayed the same.

The meters are relative to the max output voltage setting.

For example-if you are just hitting max output level with the voltage at 50V, then when you put the voltage at 100V the meters will ready 6dB less.

It is all relative.

So first you have to know what the voltage limit settings are.
Next you need to know if the voltage limits are in RMS or PEAK voltage. They are peak on the real units.

THEN you can start to figure out what the short impulse power is-figuring out the load impedance as well.

The average level will be a good bit lower than the displayed "peak" levels.
post #3347 of 4387
Quote:
Originally Posted by notnyt View Post

Try it on a different circuit. Measure the voltage on your circuit also. It's odd that it fails in the AM but not later?

I have tried 3 circuits now, all had good measured voltage around 119v.

I think I may be on to something though... I tried reversing the 80mm fans again so they blow back to front, and sure enough it is rock solid stable. It heats up pretty quickly even with no load this way, and I'm guessing the last two days I had pushed the amp hard enough while troubleshooting it that it warmed up.

This gives ne the impression that it must be heat related - possibly a bad solder joint somewhere? Trouble is I can't for the life of me find it.

Quote:
Originally Posted by Jason kiDD View Post

LOL as a gimmick i would put the fans back the way they were..

See above... it actually worked haha
post #3348 of 4387
Quote:
Originally Posted by cubalis2 View Post


I think I may be on to something though... I tried reversing the 80mm fans again so they blow back to front, and sure enough it is rock solid stable. It heats up pretty quickly even with no load this way, and I'm guessing the last two days I had pushed the amp hard enough while troubleshooting it that it warmed up.

...See above... it actually worked haha

Or, that the direction of the airflow actually matters to the cooling scheme,
post #3349 of 4387
Thread Starter 
Quote:
Originally Posted by whoaru99 View Post

Or, that the direction of the airflow actually matters to the cooling scheme,

There's probably a cold solder joint or a failing component or something that is reconnecting as it heats up. The airflow in these is designed from front to back. It's possible something got cooked when you ran it with the fans wrong.
post #3350 of 4387
Those are my thoughts too. I'm going to keep looking for a solder joint which is any easy fix if I can find it. Any ideas where to focus the search based on the way it cycles? I'll try switching one fan around at a time to see if I can isolate a side at least, but I have a feeling it will be the right side (looking from the front) based on how hot it gets there.
post #3351 of 4387
Power board like you said.. Make sure everything is discharged however before poking around.. Better to be safe than sorry.. cool.gif

There maybe actually an issue with the fan itself.. Its not unheard of. I would check there first by doing one at a time like you said..
Edited by Jason kiDD - 9/19/13 at 11:20am
post #3352 of 4387
Hey Jason kiDD, this is the amp you ordered for me a while ago. It has been working for a long time, this is why I don't touch them ever! I just rack them and connect them and when working can't be touched!
post #3353 of 4387
Quote:
Originally Posted by MKtheater View Post

Hey Jason kiDD, this is the amp you ordered for me a while ago. It has been working for a long time, this is why I don't touch them ever! I just rack them and connect them and when working can't be touched!

Okay cool.. Figured it may have been one or the other which is why i asked..
post #3354 of 4387
I just listed a fp14k in the classifieds.
post #3355 of 4387
OK, so I may have missed this. But how does this hook into a receiver?

edit: Pioneer VSX-822
post #3356 of 4387
Quote:
Originally Posted by fieroloki View Post

OK, so I may have missed this. But how does this hook into a receiver?

edit: Pioneer VSX-822

XLR to RCA cable. They're on monoprice and amazon.
post #3357 of 4387
So, I won't be able to use this with my receiver. Bummer.
post #3358 of 4387
Quote:
Originally Posted by fieroloki View Post

So, I won't be able to use this with my receiver. Bummer.

 

Yes you can, the FP14000 has XLR inputs so you need an RCA to XLR cable. The RCA end connects to your receivers subwoofer output and the XLR end connects to the amp.

post #3359 of 4387
Oh duh. I had a brain fart and was thinking I needed to run all channels through it. Thanks!!
post #3360 of 4387
I'm thinking of doing a DIY LMS build and am considering one of these amps. I've read a lot of builds and this seems to be the go to amp. I have question......in general are these amps reliable? I see within this thread that people are having problems but I'm sure they are all not like that . I just don't want to purchase something from china and not be backed by it.
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