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Hello all. I am going to cut out as much of the 'grammar'
as I can and just note the facts, sort of.
Found old Forum on Web: Guru posted " must be 300mV pp at o/p of receiver opamp".
Checked mine : 600mV and bad crossover distortion. Fixed Xover with hard pull-up
(LM35
.Found horrible waveform at output of DISC op amp. Sort of damped oscillations.
MC33178 (same as Tesoro) arrived in post.Removed pull-up & LM358, fitted it. No Xover,
horrible wform gone - was slew rate then.Still got 600mV pp.
Bought some unknown coils on Ebay, 3 for £5.00 - worth a punt.
Tested mine (10" - ooh Matron. You need to be English
). Tuned at 10kHz
Dime detected at 15cm (yeah, been across the sea a few times).
1" washer det at 17cm.
Tested 7" unknown from Ebay. F went up to 13.86kHz 300mV pp as ordained.
Dime at 16 cm, washer at 19cm.
Ground balance much better.
Minor mod to 4024 (use pins 6/5/4 - more pleasing tone.
My unit now 99% as Tesoro design. Shame.
First board I made had faults. Fixed it, sprayed with conformal coating, ruined it.
Built another - much better layout, used almost same parts as Tesoro. Way way better.
I guessed Freq when I built - didn't know what Bandido runs at. Seems my coils are crap -
but I did make all the rest, twice.
Planning field trip after good back garden tests.
as I can and just note the facts, sort of.
Found old Forum on Web: Guru posted " must be 300mV pp at o/p of receiver opamp".
Checked mine : 600mV and bad crossover distortion. Fixed Xover with hard pull-up
(LM35
.Found horrible waveform at output of DISC op amp. Sort of damped oscillations.MC33178 (same as Tesoro) arrived in post.Removed pull-up & LM358, fitted it. No Xover,
horrible wform gone - was slew rate then.Still got 600mV pp.
Bought some unknown coils on Ebay, 3 for £5.00 - worth a punt.
Tested mine (10" - ooh Matron. You need to be English
). Tuned at 10kHzDime detected at 15cm (yeah, been across the sea a few times).
1" washer det at 17cm.
Tested 7" unknown from Ebay. F went up to 13.86kHz 300mV pp as ordained.
Dime at 16 cm, washer at 19cm.
Ground balance much better.
Minor mod to 4024 (use pins 6/5/4 - more pleasing tone.
My unit now 99% as Tesoro design. Shame.
First board I made had faults. Fixed it, sprayed with conformal coating, ruined it.
Built another - much better layout, used almost same parts as Tesoro. Way way better.
I guessed Freq when I built - didn't know what Bandido runs at. Seems my coils are crap -
but I did make all the rest, twice.
Planning field trip after good back garden tests.