Can We Fix The Problem With The Bluetooth Mod on the Amstrad
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- Опубліковано 22 сер 2024
- This is a follow-up video to this week's Mid Week Palate Cleanser.
I figured out that I had connected power for the Bluetooth board to an inappropriate location, so we'll fix that.
With the help of Noel Llopis, I also discovered an issue with the audio signal path. We'll sort that out, too and get this Amstrad CPC 464 working great!
Hope you enjoy the video!
Thank you for watching
Todd
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#bluetooth #amstrad #cpc464
Interesting video. I am waiting for Commodore, but do enjoy seeing what is happening with other retro computers. Did not see you on the live stream :( hope you will be there in the future.
Thanks. I'll get a Commodore video out soon. Been a little tied up recently. As for the stream, I've left the group for personal reasons. Steve mentioned it briefly at the start of the stream.
great video / content, it has caused me to buy some of these modules to try on some systems ..i will have to try them with OTLA as well ..
You'll have to let me know if it works with OTLA. I haven't experimented with OTLA in any way at all. Thanks for watching!
This got me thinking. You used only one of the 2 stereo channels coming out of the bluetooth module. I believe you did that to prevent shorting the two channels to each other. I don't think that will cause any problems since both channels will always have the exact same signal, (when one is high, the other is also high and vice versa), they won't short each other. Nevertheless, I thought what a better solution would be to use both channels. First, I thought of an op-amp summing amplifier but that would be an overkill. Then I thought of just putting one resistor to each channel and you released this video. You have the resistor for a totally different problem, but it will work both ways. Why not put another resistor to the other channel and add that too? I would start with something like 470 ohms for each channel (will work well for mixing) and work my way up until the other problem disappears too. The lowest value that fixes the pull-down problem will be the right one.
Thank you for the suggestion, Bora. I do appreciate it. Remember, I'm really not experienced in analog electronics and forgive a dumb question. What are you trying to accomplish by uniting the two channels?
I didn't have a reason for using only one channel apart from that's the way it was done by Shane, the viewer who gave me the suggestion.
Am I right in assuming that using both channels like that would boost the signal level (as long as the two signals are in phase with each other)? I'm not sure the CPC would like that. I think it's expecting a signal in the 0-5v range. Though I didn't scope the output signal from the BT module, seeing as it's 5v input, I was assuming it was a TTL level output. Yeah, I know I shouldn't assume.
Sorry. I know I should probably have a better understanding. Just clue me in where you're going with this. It's probably a very bright idea and I'm just not knowledgeable enough to understand.
@@YARC-1981 Signal from the BT module will most probably be line (maybe headphone) level, I would doubt it will exceed 1 or 1.5V peek to peek, regardless of the 5V power in. They are meant to drive headphones or amplifiers from line in, both will not like a 5V signal at all. Combining both channels will boost it significantly. I never had an Amstrad CPC464, it seems it has a good "ear", but Sinclair Spectrums (which I know inside and out) usually are a bit hard of hearing and they have a hard time hearing from ear phone output of smart phones. As long as you have no problems with just one channel input to Amstrad, go for it, but the same setup may not work for a Spectrum. That's why I recommended using both channels.
Thank you for the explanation. It makes sense now. I'll probably leave the CPC as-is since it's working, but I do have a Speccy that I'll probably do the mod on and I'll definitely use your suggestion. It'll also probably come in handy on other machines I put these into. I appreciate the assist. Cheers.
I was wondering why had you change from left output to right on the bt module?
I don't remember doing that, but if I did, it was unintentional and irrelevant. Both channels have the mono signal on them.
@@YARC-1981 okay i understand. I am in a problematic situation: connected everything ok but used 1k, then 2k resistor, and not everything loads: read error occur sometimes. I will try the 3k since I left the case open ;) idk i will check. Anyway thanks for the tutorial and for the helphul response :) much appreciate anything you do on this channel :)
You're welcome. I've found that different machines seem to require different signal levels to load, so keep at it. You'll find the right combination eventually.