lr3107:
This is an English speaking forum. If you wish to post in another language you must also translate to English.
Thank you.
This is an English speaking forum. If you wish to post in another language you must also translate to English.
Thank you.
Production testing is time limited so we calibrate parameters at certain reference temperature (23°C).
You have time and modules already installed on heatsinks, so the best way is to wait for amp to warm-up (42-45°C) and then perform parameter's calibration.
VAS bias 15 mA, complete module bias 280 mA (current through +supply wire), output DC offset 0 mV. 😉
That's exact implementation for which First One is intended to, multi-way active systems. Congratulations, enjoy.
Tested with coax cable, it did make a difference, but didn't solve the problem... However the time between the plops is increased a lot. Now it's a plop every 5 seconds (approx).
Hope Andrej can give me some tips to get this solved, as I am getting a bit depressed as I wasn't able to listen to music for quite some time now.
Hope Andrej can give me some tips to get this solved, as I am getting a bit depressed as I wasn't able to listen to music for quite some time now.
Did some more testing. I tried different LS cables (shorter and different construction) and the coax interconnects. Still plopping sound. Than I swapped my 'old' interconnects back in and the plopping sound was gone! Time to play some music. Imediately noticed something not right with the left channel. Strong destortion in the mids and highs. Than I removed the ground cable at both IEC connectors connected to the amps and fitted back the coax ic's. This completely solved the problem and I could play music finally! I thought I did solve the problem by disconnecting the ground from both amps, so I swapped back in my new LS cables (I do need longer ones in my new house!) and the problem was back again.....
Conclusion: both IC and LS cables do have an influence on this problem, ground also has an influence.
Please advise me what to do, to be able to play nice undistorted music with all sorts of ic's and ls cables.
Thanks,
Mark.
Conclusion: both IC and LS cables do have an influence on this problem, ground also has an influence.
Please advise me what to do, to be able to play nice undistorted music with all sorts of ic's and ls cables.
Thanks,
Mark.
Mark Verhoeven, sorry you have to move back the old house 🙂.
At end of new cables try play music into pure resistors and put high impedance headphones parallel and listen if this clears things. If problem is still there could sound as RL serial filter on FO needs a little bit higher inductor to fight capacitance value in the new speaker cable. If the test show problem goes away could sound as linearizing impedance at speakers could help, what speakers do you use.
At end of new cables try play music into pure resistors and put high impedance headphones parallel and listen if this clears things. If problem is still there could sound as RL serial filter on FO needs a little bit higher inductor to fight capacitance value in the new speaker cable. If the test show problem goes away could sound as linearizing impedance at speakers could help, what speakers do you use.
Last edited:
Can-you ensure your preamp have a 1K serial resistance right at his output, or did-you tried to add one right at its output plugs ?
Hi Esperado,
My preamp is tube pre with transformer output. It has low Zout. (approx. 50 - 100 Ohms)
No serial resistor has been used.
Mark.
My preamp is tube pre with transformer output. It has low Zout. (approx. 50 - 100 Ohms)
No serial resistor has been used.
Mark.
Mark, you were talking about "ICs", can-you give precise details or schematic of your preamp/amp connections wires ?
Is your preamp output symetrical, and do-you use some SSM2141 reciever at the input of your amp ?
Is your preamp output symetrical, and do-you use some SSM2141 reciever at the input of your amp ?
Last edited:
With "IC's" I am talking about Interconnect's between pre and FO.
No schematic needed, it's just my pre with RCA out connected with interconnect cable to FO in. I do have different types of interconnect cables. Andrej suggested to try coax for interconnect, I also tried that without success..
No receiver, just the RCA input terminal directly connected to the input of the FO.
In my opinion the FO is just too sensitive for cables and or LS load. With my previously owned Magnepan 1.6R (almost resistive load), there were no problems every cable worked fine. Problems arrived when I got new loudspeakers... And those problems could be solved too by using different interconnects. But now with my new LS cables (I can't use the old ones, as they are too short), I can't solve the problem anymore...
Mark.
Have you bought any new electrically powered equipment for the new house? If so, unplug every new item - one by one - and hear if there are any changes. Just a thought. Although I have had problems of this sort the symptoms have been totally different.
The first think you have to ensure is the problem don't come from your preamp.
Do-you have a fast oscilloscope, and can-you monitor whats happens at the input of your amp, when the "plops" occurs ?
First one is supposed to be very stable and insensitive, even with heavy capacities loads (if correctly protected with an output coil).
Do-you have a fast oscilloscope, and can-you monitor whats happens at the input of your amp, when the "plops" occurs ?
First one is supposed to be very stable and insensitive, even with heavy capacities loads (if correctly protected with an output coil).
I don't have an oscilloscope, but I can't imagine ANYTHING is happening with the pre's output when not switched on. The problem occurs when I connect both amps to the pre. Connecting just one, no problem. The amp can be switched off, or mains cable disconnected completely. Same problem.
Have had my pre connected to several (at least 10) different power amps (also recently) and never had any problems...
The "plopping" sound is occurring with constant interval between plops. You can see the woofer moving as far as it can possibly move. (DC?)
Have had my pre connected to several (at least 10) different power amps (also recently) and never had any problems...
The "plopping" sound is occurring with constant interval between plops. You can see the woofer moving as far as it can possibly move. (DC?)
With what not switched on ?
If you want us to understand your problem, please describe precisely all the test you had done and their results.
As-it i have no idea of your set-up.