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+3 sound quality?

Posted: Sat Jan 11, 2020 2:30 pm
by animaal
Hi. I had a +2 (grey) back in the day. It was my only computer for many years, until I eventually downgraded to a Pentium PC :)

More recently, I managed to get myself a +3. I used to lust after a Spectrum with a disk drive and now I have one.

I refurbished it - changed the capacitors, Scart fix, audio fix. Regarding the audio, it was just awful! now that it's fixed, it's great, similar to the sound quality of my old +2.

Was this a big deal in the 80s? I don't remember reading about +3 sound quality in magazines, but I might not have taken too much notice if it was discussed.

If I had turned on a new +3 and heard the sound quality, I would probably have returned it, thinking it was faulty. I suppose in a way they all were.

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 2:52 pm
by Ast A. Moore
I guess the +3 was not produced in substantial quantities, unlike the +2A, in which the issue was later corrected (and the new model received the +2B moniker). There was technically a +3B, but it was extremely rare and, as far as I can tell, was only released for the Spanish market.

That said, the original 128K and +2 also had a sound issue—the beeper and AY-chip audio were extremely unbalanced. Those were never officially fixed, in spite of several logic board revisions.

I never owned any of the Amstrad machines back in the day, so I can’t say for sure. When I purchased a Toastrack a couple of years ago, I fixed the audio myself, and my Amstrad machine is a +2B.

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 3:34 pm
by patters
I certainly never knew of anyone with a +3, which supports that hypothesis.
Incidentally, the toastrack which I recently bought has had the Beeper-AY resistor fix, but the beeper is still a fair bit louder. However, overall a lot quieter than my 48K when connected to my TV. After your own fix, are they more or less equivalent volume, or does the beeper still out do the AY? I saw there are several ways to do the mod, so I'm wondering if it's worth me re-doing.

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 5:31 pm
by AndyC
Isn't the beeper thing intentional? The manual describes the beeper volume as being as loud as all three AY channels at full volume.

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 5:59 pm
by animaal
Yes, I remember reading that about the +2, which is why I never really thought it was a bug.

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 6:56 pm
by 1024MAK
animaal wrote: Sat Jan 11, 2020 2:30 pmIf I had turned on a new +3 and heard the sound quality, I would probably have returned it, thinking it was faulty.
Apparently some people did...

Mark

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 7:02 pm
by Ast A. Moore
patters wrote: Sat Jan 11, 2020 3:34 pm After your own fix, are they more or less equivalent volume, or does the beeper still out do the AY? I saw there are several ways to do the mod, so I'm wondering if it's worth me re-doing.
I went for them being more or less equal in volume. It really all depends on the value of the resistor you use. Here’s my mod:
Image

(Note: This will only affect the volume on the MIC output; not through the RF modulator.)

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 7:05 pm
by Ast A. Moore
AndyC wrote: Sat Jan 11, 2020 5:31 pm Isn't the beeper thing intentional? The manual describes the beeper volume as being as loud as all three AY channels at full volume.
Hmm. Can’t find it anywhere in the manual. Could you tell me the page number? (I just went through this searching for words like “loud” and “volume” to no avail.)

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 7:14 pm
by animaal
If you look at the +2 manual, page 121:

"As previously mentioned, BEEP is louder than a single channel of PLAY, but if all three channels play a note at volume 15, then it should be at the same level as a note produced by BEEP"

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 7:32 pm
by Ast A. Moore
animaal wrote: Sat Jan 11, 2020 7:14 pm If you look at the +2 manual, page 121:

"As previously mentioned, BEEP is louder than a single channel of PLAY, but if all three channels play a note at volume 15, then it should be at the same level as a note produced by BEEP"
Thanks! That explains that, then.

By the way, the volume difference on the MIC jack of the Toastrack (or the SOUND jack of the +2) is much more drastic than on the RF. That might explain why most people didn’t notice it.

Re: +3 sound quality?

Posted: Sat Jan 11, 2020 8:36 pm
by Swainy
The sound problem was mentioned in the magazines at the time. I think Crash even had a fix guide.

A friend of mine had a +3 and it sounded awful compared to my grey +2.