No tape loading sounds on +3

[MrMarkian]

hi all, I have recently picked up a spectrum +3 and have attempted to load games using the tape input socket, however I cannot hear any loading sounds is this normal on this model and if so is there a hardware hack to stop it from muting the sound? if I turn the tape volume down enough then the sound comes through but then the +3 doesn't recognise it. many thanks

[Ast A. Moore]

How is the lead for loading games wired? How do you monitor the sound output from the Spectrum?

The input jack on the +3 should be wired as follows:

Tip: sound output
Ring: tape input
Sleeve: ground

[MrMarkian]

is setup like this, which isn't ideal i know.

mobile phone to amplifier amplifier to spectrum with a stereo cable, it seems to load some games even with the muted sound but a lot do not.

I have a cable which came with it with separate mono plugs but the spectrum won't detect anything at all with that cable even though the sound comes through.

and I'm using a TV via rf to monitor the sound

[1024MAK]

So, as Ast A. Moore says, the socket on the +3 is a three terminal type. Also known as a stereo type. But unlike a normal stereo connector, one channel is OUTPUT and one channel is INPUT.

So a stereo to stereo lead is unlikely to work properly. You need a lead which breaks out each channel to two separate mono connectors. One mono connector will have the sound OUTPUT from the ZX Spectrum. The other is the tape INPUT.

Just like the earlier Sinclair computers, when attempting to LOAD, you have to get the volume “just right”. Too low or too high and it won’t work.

Mark

[Guesser]

I have a cable which came with it with separate mono plugs but the spectrum won't detect anything at all with that cable even though the sound comes through.

As you have a stereo source/amp, you should probably determine which of the two mono jacks is the ear connection (input to the spectrum) and replace the connector with a stereo jack. Connect the shield to the sleeve and the inner conductor to the tip, that will then be the correct wiring, and any issues beyond that will be down to signal level or a hardware fault. Hearing sound but no loading suggests you're feeding the signal into the mic connection rather than ear, and driving the audio output directly.
Ear is connected to the ring of the 3.5mm jack in the +3.

[Ast A. Moore]

I recommend making a universal lead for loading games, suitable for all Spectrums. It has a TS (mono) plug on one end and a TRS (stereo) on the other. The sleeves are connected, and the tip of the mono plug is connected to the ring of the stereo plug. The tip of the stereo plug is left unconnected.

When loading games into 48K/128K Spectrums, you insert the mono plug into the Spectrum’s EAR socket, and the stereo plug into the audio source’s output. When loading into the +3 (or a modded +2A), you simply swap the lead’s ends.

It’s best not to drive the Spectrum’s ULA/gate array with a signal that swings below zero volts (i.e. goes into the negative range). The audio input on all Spectrums (aside from the +2) is protected by a bypass diode, which ensures that, while the output is not (obviously).