Tape loading from PC
So, I found that I had been using the wrong audio jack socket on my 48k for tape loading (my spectrum is in a third party case, so there are not labels). This may be why I am unable to load some programs.
My setup is as follows: My laptop running unix with mplayer playing a wav file. The wav was converted from tzx using tape2wav from the fuse emulator package. I'm using a mono audio jack from my laptop to the right audio jack (as you are facing the keyboard front on as though you were typing). I believe this is the "ear" socket.
The problem is, i don't think my laptop is loud enough, even though my laptop is at full volume. I even tried using mplayer's software volume control at 1000% (its probably clipping my then anyway).
I found this similar issues, but it seems it was unsolved:
http://www.worldofspectrum.org/forums/showthread.php?t=40882
Any tips? :confused:
My setup is as follows: My laptop running unix with mplayer playing a wav file. The wav was converted from tzx using tape2wav from the fuse emulator package. I'm using a mono audio jack from my laptop to the right audio jack (as you are facing the keyboard front on as though you were typing). I believe this is the "ear" socket.
The problem is, i don't think my laptop is loud enough, even though my laptop is at full volume. I even tried using mplayer's software volume control at 1000% (its probably clipping my then anyway).
I found this similar issues, but it seems it was unsolved:
http://www.worldofspectrum.org/forums/showthread.php?t=40882
Any tips? :confused:
Post edited by vext01 on
Comments
Some PC audio outputs can't produce a signal quite strong enough for a Spectrum. A small amplifier of the sort intended for driving headphones or a set of amplified computer speakers with a headphone output may prove helpful. If the PC is running Windows, check the audio driver settings. Some have an extra 'boost' setting and if it has equalisation controls, set all the bands to maximum.
Finally, if you are generating audio from an archive file (i.e. a TZX or similar file), you might try a different utility to do so. Quite a long time ago, I remember noticing that the tape2wav tool that comes with the FUSE emulator produced (to my ears) tones that were slightly off from those generated by a Spectrum and it wasn't easy to get a Spectrum to load from these files. Perhaps there are other such utilities that aren't quite perfect. I've always found playtzx to work well.
I find the best method is to convert tzx to mp3. It's wasteful of space, but the output of mp3 players seems to be better quality.
Remember to disable any enhancements (reverb, equalization etc.) your soundcard control panel, if present, could apply to affect the output.
The problem is the low level only. There a two principle ways to increase that level:
1. You can use an amplifier. For example use an external active speaker with a headphone socket.
2. Or you can use a small transformer for example with a ratio of 1:4. In that case you don't need a power supply to increase the level.
I did successfully load programs from soundcard of a notebook using an active speaker with headphone output.
Greets Ingo.
On the other hand, it's not always a problem. The Soundblaster card in the computer I'm using now can output a signal with an amplitude quite a bit beyond what is needed by a Spectrum. The audio output from laptop computers is often much more feeble, though.
That alone would not cause any problem.
Thinking about it, you are right.
When I think how much noise there used to be on third or forth generation tape copies and they still worked.
I have been using a Laptop, so perhaps I'll have to try on my desktop and see if that works any better with the larger output.
I had this problem with SiS 6326 and SiS 530 chipsets. The waveform was inverted, started negative.
Greets ingo.
Just to clarify. Actually never had a go with these chipsets and a Speccy. Just pointing that these chips reverse the waveform. They're Old chipsets though.
I failed at trying to load from a PC although never actually tried a second time. To load programs I use a divIDE, a tape recorder or a mp3 player equalized the best as I could. Not all programs load from the mp3 player though. Just like the old days.
My friend has a bunch of spectrums. We found only a +3 to work, so I couldn't try another 48k. But anyway, I loaded a game from my laptop first attempt using a stereo jack lead.
I'll have to try again when I get home to my 48k...
Don't forget that for a 48K Spectrum at least, you should use a lead of the type I described earlier in the thread. A stereo to stereo or mono to mono audio lead will cause problems if used between a Spectrum and the stereo output of a PC/audio player etc. (It'll short the two channels together).
The other pictures shows the equalization setup I'm using. If someone knows how I could do it better, please let us know. This is the best I came up with.
http://www.flickr.com/photos/rdkarlov/sets/72157631780836860/
I have built the cable to Zorn's specifications, but that alone is not enough. Seems i need to amplify the signal, or I could try (as others have), MP3 players or phones as an audio source.
Will let you know how I get on.
You may check also EAR socket for contact quality-this is often source of the problems (signal is weak or disappears). I had such 128k recently.
As was mentioned, the sound level from my Laptop is far too low to load successfully.
I've been using WinTZX and it works pretty well most of the time. However, there does seem to be a bug when selecting files, so I am off to try Tapir!
I occasionally use (one half of) of the original Speccy tape lead to load PlayTZX audio files from the headphone socket of my laptop to the EAR socket of the Spectrum. Am I putting my hardware at risk?
Mono to mono do not short two channel together, but one channel to ground, and the same with Stereo to stereo which will be sorting one channel to ground in Speccys plug. This may cause problems with some unprotected PC Hardware, but I never had some.
I use old ISA cards with Passive SPK Out settings because they have strongest output level. New PCI cards do not work because there is a kind of law which forbids too high output level on Earphone output (because some kids has ruined their ear input using too high volumnes).
Again, all Spectrums require some sort of external amplification when loading files other than from physical tapes, especially the 16K/48K/+/128K, because they must be fed a very strong signal, otherwise they won't "catch" it.
- Desktop PC soundcards usually have a Line Out, while Laptops normally have a Headphone Out only. Headphone ports receive an extra boost, which means that at high volumes, the signal will be distorted (if it isn't too quiet in the first place)
- Desktop PC soundcards mostly work well, no extra amplification required.
- Most external USB soundcards work well, too.
- My personal favorite are regular CD players (not portable ones) - they have a very clean signal and are always loud enough, and don't require additional amplification. Plus, they normally have RCA ports, which elegantly solves the problem of converting from stereo to mono.
cheers,
-utz
A stereo-stereo lead usually doesn't work properly at all as the way the mono socket in the speccy is constructed means that the right channel is being grounded again but this time to the speccy's ground, while the actual sleeve of the jack is left floating. This means that the circuit relies on there being a ground return besides the the audio cable outer (since it's not connected at the speccy end). If you are using a batter operated cd player, or a laptop obviously there can't be one. Even if both the source and the speccy are both connected to the mains that doesn't necessarily mean that their grounds are both at earth potential, there can also be a lot of noise introduced this way which will disrupt the loading.
TL;DR version: it's best to just make up the correct lead in the first place, but if you must use the wrong thing then a mono-mono will have the greater chance of success.
For a proper tape loading cable simply connect a stereo jack to a mono jack tip to tip and sleeve to sleeve, leaving the ring of the stereo jack unconnected.
[FONT=Courier New] PC soundcard line out Speccy ear socket T R S S T _______.-------. .--[/FONT][FONT=Courier New][FONT=Courier New]-----.[/FONT][/FONT][FONT=Courier New][FONT=Courier New][FONT=Courier New]_______ [/FONT][/FONT]<_|_|___| |--------------|[/FONT][FONT=Courier New][FONT=Courier New] |_____|_[/FONT]> '-------' [/FONT][FONT=Courier New]'-------' [/FONT]Obviously the same cable can be used between the line in and Mic to record saving tones from the speccy too.
Not from my old cmedia PCI soundcard they didn't. I have a feeling that I can load from the onboard HDAudio in this PC too if I configure the output as a line out but I can't remember when I last loaded anything by tape into the 48k.
I bought a little amp board off ebay and wired it up to an old 9v mains supply, then soldered on the correct leads on either side (pretty much what guesser's diagram above shows, but with an amp in the middle).
Just plug the stereo jack (+3 end) into your soundcard and one of the mono jacks (tape deck end) into the ear socket.
If you want to load into a +3 from the PC you have the same issues as with the 48k i.e. the +3 tape leads have mono jacks at the tape deck end. Again you can plug these in to the PC and probably get away with it however if you never plan to use the lead with a real tape deck again I would personally change the jacks for stereo ones. Again connect the signal wire to the tip and the braid to the sleeve, leaving the ring disconnected.*
*If you want to use this lead to get the audio out from the AY etc to use with a composite modded +3 or an RGB monitor you can join the tip and ring together on the "Mic" lead half of the cable so that the audio from the speccy goes in on both channels. In fact you can do that for the Mic lead on the 48k too. Technically speaking you shouldn't do this with the Ear lead as this connects both channel outputs together in the soundcard though I've never known it do any harm.
Hrm, what threshold voltage does the speccy need? I suppose you're right as looking at the schematic there's a 1k resistor sitting across the input so the line level will be below 2V.
Perhaps I configured as a headphone/speaker output then :D
You are of course quite right that turning the headphone amp on will deliver a greater voltage across a high impedance input. I was just being dim.
Some sound cards and laptops will use a audio amplifier chip that has short circuit protected outputs, but not all are rated to handle a continuous short circuit.
If you cannot solder, ask nicely and I am sure someone will build a cable for you.
It's about half-an hours work (not including ordering parts and trip to the post office / post box).
Mark
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I have been working with audio codecs/amplifiers for a few years now and one pretty universal feature is short circuit protection. I doubt you will find a singled consumer device these days that can be damaged.