I have my LP10 connected to a vintage pre-amp/power amp. The pre-amp input (0.25V) is way too sensitive for the LP10’s output of around 1V. Consequently I have the Max Volume setting at the minimum 30% in the GoControl app all the time.
I don’t know about you but my LP10 is constantly losing its network connection even though it’s less than 4m from the wifi access point. It’s a continually frustrating issue that prevents me from recommending the device to friends. Anyway, sometimes when I reconnect it to the network the settings in GoControl are all reset. Settings including the maximum volume are returned to defaults and all my saved custom EQs are gone. This presents a real danger to me because when it’s turned on again the signal is so hot that it nearly sends my old amp DC. I can’t expect my whole family to download the GoControl app and check the settings before they listen to music every time. I’m going to have to buy some expensive inline attenuators to make it safe to use. (I’d recommend to Arylic that they offer suitable hardware attenuation as an optional accessory).
I can’t be the only person using this device with vintage equipment. Does anybody else experience this issue or have any advice for me?
There are actually two separate problems here, and I wouldn’t rely on the Go Control maximum-volume setting to solve the first one.
If your vintage preamp reaches its normal input level at around 0.25 V and the LP10 can produce about 1 Vrms, you’re feeding it roughly four times the voltage it needs. That’s about a 12 dB level mismatch.
I’d put a fixed passive attenuator between the LP10 and the preamp. Something around -10 to -12 dB would put the LP10 much closer to the level the vintage input was designed for. Then you can leave the LP10 at a sensible output level without depending on a software setting surviving a reboot/reset.
You don’t necessarily need an expensive commercial attenuator either. Electrically it’s just a passive resistor divider, although the correct resistor values should be chosen with the preamp’s input impedance in mind. If you can post the make/model of the preamp—or its input impedance—we can work out appropriate values for a pair of RCA attenuators.
One correction: the high LP10 output shouldn’t actually “send DC” into the amplifier. The more likely problem is severely overdriving the preamp input, clipping and potentially producing a very loud transient/output. Your concern about protecting the vintage equipment and speakers is still justified.
The Wi-Fi/settings-reset problem is separate and I’d report that to Arylic. Losing custom EQ is annoying; losing a configured maximum-volume limit is potentially a safety issue if someone is depending on that limit. I don’t know you’re WiFi setup, but, I use multiple SSID’s in my home and separate things like streaming & IoT devices from home computers & mobile devices and run the SSID’s on different channels (that may be a rabbit hole for a lot of users. It might be easier to move it to another frequency [5Ghz] if your WiFi device supports that).
The LP10 supports both 2.4 and 5 GHz Wi-Fi and also has a 10/100 Ethernet connection, so being only 4 m from the AP doesn’t necessarily prove the Wi-Fi link is healthy. I’d check which band it’s actually using and try Ethernet temporarily. If the disconnects disappear on Ethernet, you’ve isolated the network problem from the LP10/app/firmware problem.
But regardless of what fixes the Wi-Fi problem, I’d still install the passive attenuation. A software volume limit shouldn’t be the thing protecting a vintage amplifier.
I restore vintage European tube radios and integrate their DIY pre-amp PCB boards into them so my challenge is the opposite of what you’re experiencing where there is about a 20%-30% drop in volume from the Pick Up (PU/TR) so I have to also install a small 5W PCB Amp.
Thanks so much for your advice. I’ll work on my WiFi setup to see if I can make it more reliable and let Arylic Support know about the GoControl issues.
I’m handy with a soldering iron and I’d love to have a go at making my own attenuators. My pre-amp is an obscure Australian made ME Sound ME15. I think the input impedance is 68kOhm and the sensitivity is 6.4mV. I asked AI what resistor values to use and it suggested 12kOhm + 2.2kOhm shunt. Let me know if you think that would work.
Your 12 kΩ series + 2.2 kΩ shunt idea will work electrically, but I’ve found some additional information on the ME15 that changes the calculation slightly.
The ME line-stage input appears to be approximately 100 kΩ. With your 2.2 kΩ shunt resistor in parallel with that 100 kΩ input, the effective shunt resistance is about 2.15 kΩ.
So your divider becomes approximately:
12 kΩ series + 2.15 kΩ effective shunt
That gives about -16.4 dB attenuation.
In practical terms, the LP10’s maximum ~1 V output would become roughly 150 mV at the ME15 input.
There’s nothing wrong with doing that if you want a fairly conservative hardware limit. In fact, given your concern about the LP10 occasionally losing its stored Max Volume setting, I’d rather have a little too much passive attenuation than too little.
If your target really is closer to the 0.25 V level you originally mentioned, however, you only need about -12 dB. Something around 15 kΩ series + 5.36 kΩ shunt would get very close to that with the ME15’s 100 kΩ input.
So I’d look at it this way:
12 kΩ + 2.2 kΩ: ~-16.4 dB → 1 V becomes ~150 mV
15 kΩ + 5.36 kΩ: ~-12 dB → 1 V becomes ~250 mV
Personally, for your particular situation I’d be quite comfortable with your 12 kΩ/2.2 kΩ choice. You’ll lose some maximum available level, but the LP10 still has plenty of output, and it gives you substantially more protection if its software volume limit resets again.
I’d use 1% metal-film resistors, duplicate the network identically for left and right, and put the attenuator close to the ME15 input.
One other thing: I wouldn’t base the attenuation on the ME15’s quoted 6.4 mV sensitivity. That appears to be a gain/rated-output specification rather than the maximum acceptable line-input voltage. Designing around 6.4 mV would result in an unnecessarily huge amount of attenuation.