Turbo AY strangeness

[sirmorris]

Sorry Moggy, I thought you meant the turbo bit..!
Here's the main section:

zxpand+-ay.png

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[Moggy]

As for Yamaha "improving" the analogue outputs I can only assume,as you didn't go into any detail, that you mean bigger out-put voltages/currents. In practice I have always found my AY to be the better driver of an amplifier, when inserted separately into any stereo set-up my AY plays any common tune louder at a given set volume than the YM, but then again my resistor pattern on the AY's out-puts is different to the "golden ratio" setup Charlie uses for the YM so perhaps that's where the answer lies?

A quick glance at the pdf's for these two chips give a high out-put of over 2volts for the AY and 1.35v for the YM.

Sorry, my comments were pure speculation. I was travelling on a train when I posted it. Hence I did not read the datasheets
It sounds (sorry ) like you have practical experience, in which case I defer to your experience.

Mark















PS can I stop kneeling now, my legs hurt!

I have travelled many miles in my longish lifetime met many folk and experienced many things but have yet to meet a forum full of folk such as this who will tolerate my crabbiness my oafish witterings yet still remain friendly and decent.

Mark just like Charlie who I have also never met yet communed often I feel the same kinship and respect for you as I do for him. The teddy throwing in this case is all mine so apologies from myself and forward in peace my brother and lets solve that idiot from Oxfords problem as it's plain to see he is so dull witted about these things it' will take a couple geniuses like us to fettle him!!

[Moggy]

Sorry Moggy, I thought you meant the turbo bit..!
Here's the main section:
zxpand+-ay.png

HMMM don't think mines wired like that so will have a shufty and get back.

Also the pdf attached shows a method for summing two stereo outputs that could be useful.

[Moggy]

The diagram I use from Mr Rusky differs in look but amounts to the same thing so HMMMM more whisky I think.

[Moggy]

Not sure if this may be relevant but at first I thought it might be the YM's 30 stage volume table as opposed to the AY's 16 stage but as both my AY and YM units on separate zeddies are fairly harmonious I discounted it.

I then came across some discussion on an Atari forum where comparisons were being made between the two chips and someone wrote that a some AY chips were produced with logarithmic volume stepping whilst the YM chips volume table is linear. Perhaps the chips in Sir Morris's possession are like this and does it make a difference in perceived out-put?