ZX Spectrum load tape from android phone - Low Volume

A place to discuss the ZX80's and ZX81's younger brother - the Sinclair ZX Spectrum
NotABot
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Joined: Thu Jun 15, 2023 10:22 pm

ZX Spectrum load tape from android phone - Low Volume

Post by NotABot »

Hi all,

I recently got my first ZX Spectrum after quite a few years and am in the process of getting it running.
It's a rev 3 and in pretty good condition, I have had to replace the keyboard membrane, completed the composite mod and replaced the voltage regulator with a switch mode version.

I'm now trying to load software using my Android phone running 'ZX Tape Loader' from the Android store (seems to be a great app).
But the volume level appears to be to low??
To connect from Android phone to ZX I am using a 3.5mm stereo to dual RCA cable, then an RCA to Mono 3.5mm on the Right Channel
I've tried volume booster apps for the android unsuccessfully.
I can get the load to start and it does continue but not to completely load any software.
In fact, the volume seems to noticeably drop after the first load 'screech'

Are there any cool hacks that people know about to get this running?I'm assuming I could buy an 'inline' headphone amplifier but would like to know if that will work first.

Thanks for any help with this
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Flatulentia
Posts: 93
Joined: Sun May 14, 2023 3:58 pm
Location: Cambridgeshire, UK

Re: ZX Spectrum load tape from android phone - Low Volume

Post by Flatulentia »

I know of a potential software hack, but it involves downloading the files then editing them individually with Audacity on a PC before transferring them to your smartphone.

You may be able to include speed-loading too if it works.

Let me know if you'd like further details.
ZX81 with ZiLOG Z84 CMOS Z80, 32KB battery-backed Toshiba 55257 SRAM with charge status LED, Wilf's "Why Wait?" mod and switch-mode 5V regulator. 50/60Hz mode switch, composite video output with Zigg's back porch mod and 1080p60 HDMI output.
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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: ZX Spectrum load tape from android phone - Low Volume

Post by 1024MAK »

Hello and welcome :D

The Sinclair computers including the Spectrum were designed for use with “shoebox” cassette decks. These typically ran from a 6V DC internal supply, and could produce a surprising amount of power into an internal 8Ω loudspeaker. The ear output was the same output, just with the loudspeaker switched out.

Modern audio outputs are designed for more sensitive earphones plus the power output is deliberately limited.

Hence you need an audio amplifier. This is the conventional approach.

I use these “2PCS LM386 Module 20 Times Gain Audio Amplifier Module F Raspberry Pi Arduino”, e.g. https://www.ebay.co.uk/itm/253098292859 This listing is currently £1.66 + £1.30 postage.

There are other listings including at least one U.K. supplier. But do shop around, as prices vary…

LM386 Audio Amplifier Module
LM386 Audio Amplifier Module
LM386 Audio Amplifier Module
LM386 Audio Amplifier Module

The extra components on the tiny breadboard are just a 1N4001 diode and a 100µF 16V capacitor, as I am feeding it from an unregulated 9V DC PSU used by a computer. The diode stops the capacitor from discharging into the feed to the computer, and the capacitor smooths out the ripple voltage.

Smoothing circuit
Smoothing circuit

In my setup the amplifier is used to boost the audio output from a laptop so that the computer can ‘hear’ the “tape” audio files.

Depending on how you are powering it, may be worthwhile using a larger capacity capacitor, say 470µF rated at 16V or higher.

BTW, the Acorn Electron has nothing to do with anything, it just happened to be the item that the audio module is resting on…

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer being good this year.
NotABot
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Joined: Thu Jun 15, 2023 10:22 pm

(SOLVED) Re: ZX Spectrum load tape from android phone - Low Volume

Post by NotABot »

Thanks so much for the excellent help!!

But now I have to confess to how stupid I've been :oops:
I was connected to the MIC input on the Spectrum... whereas the EAR was correct.

After reading a few other topics I discovered this.

I just got a chance to try it again and it works loading from the Android app.

Apologies again and thanks for your help.
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Flatulentia
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Joined: Sun May 14, 2023 3:58 pm
Location: Cambridgeshire, UK

Re: ZX Spectrum load tape from android phone - Low Volume

Post by Flatulentia »

Glad you're sorted. :)
ZX81 with ZiLOG Z84 CMOS Z80, 32KB battery-backed Toshiba 55257 SRAM with charge status LED, Wilf's "Why Wait?" mod and switch-mode 5V regulator. 50/60Hz mode switch, composite video output with Zigg's back porch mod and 1080p60 HDMI output.
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1024MAK
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Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX Spectrum load tape from android phone - Low Volume

Post by 1024MAK »

Oh yeah, now ear this: also check that you have read the manual (linky)… :lol:

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer being good this year.
NotABot
Posts: 3
Joined: Thu Jun 15, 2023 10:22 pm

Re: ZX Spectrum load tape from android phone - Low Volume

Post by NotABot »

lol

I've just been so keen to get it running, I missed the obvious.
Mine even came with the manual, which I had to read to remember LOAD ""

I had a ZX Spectrum as my first PC about 40 Years ago...

Thanks again :)

I wish my soldering skills were as good as they used to be...
redgatemodels
Posts: 172
Joined: Tue Sep 05, 2023 11:56 am

Re: ZX Spectrum load tape from android phone - Low Volume

Post by redgatemodels »

NotABot wrote: Thu Jun 15, 2023 11:23 pm

I'm now trying to load software using my Android phone running 'ZX Tape Loader' from the Android store (seems to be a great app).
But the volume level appears to be to low??
Hi,

where did you find the ZX Tape Loader app? can't seem to see it on my phone in the Play Store?
redgatemodels
Posts: 172
Joined: Tue Sep 05, 2023 11:56 am

Re: ZX Spectrum load tape from android phone - Low Volume

Post by redgatemodels »

Never mind, I've found the APK on APKPure - I have it installed now. Can't wait to try this out as the tape player I have is making a horrible crackling noise which is stopping loading of games .....

Horace Goes Sking tonight, or maybe Chuckie Egg
mikeh_nz
Posts: 67
Joined: Sat Feb 04, 2023 8:03 am
Location: Seattle

Re: ZX Spectrum load tape from android phone - Low Volume

Post by mikeh_nz »

PlayZX is a great app (free, no ads) for the android phone

You can get it from the App Store or download directly off his web site

Some of the most recent android phones don’t show it in the app store, but I’ve found downloading the ArmV8 versions and installing manually worked fine.

It can handle stereo audio jacks ( see the question “Can I do anything else to increase the volume?” on the web site)
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