Solo ULDE amp

Commiserations.

Perhaps manufacturers cannot afford or be bothered with the purchase of harmonized standards? After all, complying with standards is so "square." Why spend £100 to £300 on just one of the many standards applicable?

I must admit that I search the internet for bootlegged copies of standards, but eventually realize I have to do the right thing and buy a copy.

The problem is keeping up with the many reissues, but they tend to be much like earlier versions, just with new things added.

So IEC 1938 ratings should still be valid in IEC 61938:2019, and if so, these are the ratings we manufacturers should be aiming for.

Source device: output impedance 2.2k or less, capable of driving 22k.

Input device: Input impedance 22k or greater, ability to work with a source impedance of 2.2k or less.

Source rated output voltage:
nominal: 0.5V RMS;
minimum: 0.2V RMS (-8dB of max recording amplitude);
maximum: 2V RMS ("full scale" level of a CD player. The maximum output of the maximum RMS transient)

Input device rated input voltage:
nominal: 0.5V RMS;
minimum: 0.2V RMS (as source)
overload source EMF: equal or greater than 2.8V RMS (if an analogue output of a digital player)

Before IEC 1938 was DIN, and that specified "domestic line level" as -10dBu ref 0dBu = 1mW into 600 ohms, and that relied on some mathematical understanding (you'd expect electronics engineers to be capable of that).

1mW into 600 ohms is 775mV, and -10dB is 0.316 x 775 = 245mV.

But that was in the days before audio arrogance.

Ernie wrote: Hi Graham, Buy your standards from Estonia they’re only £20-30. BSi are a right rip off.

FWIW I have occasionally fed my Oppo 203 straight into my Solo ULDE and also found no problem with the levels.