Barracuda Volume

[DOOLEY]

hello all,

I have attached a pic below to modify detectors audio response.

its quite simple, and it works !!

done this on my last 2 detector designs.

basically add the 100k pot for volume,
this is set for your preferred MAXIMUM volume level.

the diodes on the volume pot that goes to earth serve to allow a MINIMUM
volume to pass without being regulated by the volume pot.
so sets your minimum volume.

2x diodes is about 1.1 volts,
after which point the volume pot starts to limit.
this allows faint signals to pass un hindered .

depending on preference any number of diodes (1,2,3,4) can be added in series,
dependant on the headphones used,
personal deffness etc......etc......



picture shows rough version of the barra audio,
that many different versions out there,
I just picked the 1st I came to.

enjoy.

[DOOLEY]

hang on a minute ,

just had a thought,
2 or 3 diodes works well when using a single NPN
for the output drive,

but,
BARRA uses a darlington,
going to need to use 3 to 4 diodes for that.
(maybe more, personal choice)

then 3 diodes will let 0.6v through un hindered to the speaker,
4 would let 1.2v through.

[DOOLEY]

just thought i'd post an extra diagram,
if anyone wants to use it.

gives a very nice pleasant sounding audio output ,
proportional response,
and has the "minimum" diodes on the volume pot.



volume pot doesn't have to be 100k,
could be anything say 10k upwards,
but 100k wastes less power,
if that's important to you.

R1 AND C1 added to reduce the sudden impact on the +
voltage rail and feedback noise.
may be omitted ,
personal choice........

[kt315]

strange decision for me. you broke the Emitter of transistor from link FOR WHAT? where in electronics you see disrapted Emitter pin from another part of schema? give me please the examples where you found that.

[DOOLEY]

hello kt,

i'm trying to decipher your reply,
not sure what youre referring to........

going to hazard a guess it's relating to the diagram " AUDIO OUTPUT SECTION.JPG "
can't give examples of this method in use in any other schematics,
don't think i've seen any other detectors using it.

it's just the method I devised a while ago that worked well and
sounded nice ,
and provides proportional target response.
quite economical on power also.


the NPN is a simple voltage follower that applies target voltage to the speaker,
and the 2n7000 is pulsed by a clock signal for the desired tone output.
either a 555 or a divided TX signal would do.

[kt315]

can't give examples of this method in use in any other schematics --- then you are only nooby

crotcheteer

)))

[DOOLEY]

whoh whoh KT !!
ease off KT !!

WHERES ALL THIS ANIMOSITY COMING FROM ???

I decided to post a couple of times to help somebody out with a volume
related problem and I get YOU calling ME a dummy ???

I can't give examples of this circuit because I devised it myself,
I have not seen it used on any other detectors schematics so I can not
post examples,
somebody may of used it before in a design,
i'm not sure.

I may be new (7 years or so) to metal detector electronics but I am NO
NEWBY to electronics in general !!
NOR A DUMMY, thank you very much !!

me, like many others on here are striving to develop new idea's and circuits
regarding metal detectors and this sort of response is not called for.

is your aim to deter others from posting for fear of ridicule ??
or are you just having a bad day ??

I can not believe this response from you,
a long time and contributing member of the forum.

this is the sort of backlash that makes people think twice about
posting anything here,
and the content of the site will then suffer.

yes,
there are individuals on here that have great insider knowledge ,
there are professional electronics people on here from different fields of work,
then there are us mere mortals who partake in this very rewarding hobby.

just because we are not professionals or "in the game" neither makes us dummy's or
any less worthy of taking part on this forum.

[bluebenz1]

Dooley...Thank you very much for your ideas regarding the volume control....I AM a total nooby and appreciate anyones suggestions...even if i don't have the skill to convert a schematic diagram into and actual working item...!!! Anyone who comes out with totally unhelpful remarks is noted by all on this forum...and just ignored....what a total @£$%"$%£@
I have read a few of kt315 posts and find it difficult to understand the meaning behind the Lituanian/English he's trying to use....so best ignored in my opinion.
kt315, maybe you don't mean to come over as abrupt...but you do!!>>>SO CHANGE YOUR ATTITUDE..or change the forum you choose to use...

[pebe]

Dooley, I fully agree with your method. It is perfectly valid.
I am surprised KT315 cannot understand it.

[Thomas]

Guys, you are getting a little over reactive towards KT, Dooley - when KT says "strange decision for me. you broke the Emitter of transistor from link FOR WHAT? where in electronics you see disrapted Emitter pin from another part of schema? give me please the examples where you found that." I think he is saying He does not understand why you left out the emitter resistor, not a common practice. and what circuit also has that arrangement so he can under stand it. Bluebenz KT is abrupt, he has that right and does not need a attitude change, you have to like the good and live with the bad. Live and learn.

[DOOLEY]

your both welcome.



my enjoyment and reward in this hobby is trying new things,
devising new circuits,
modifying existing ones,
and designing from scratch.

it's quite annoying for someone to p1ss on my parade, ( can I say that, sorry George........LOL.....)

just thought I could help people out from time to time by sharing working solutions.

I asked many questions in the early days,
some poss quite stupid looking back now.

electronics is a never ending learning curve and process,
that's the fun and rewarding part,
(although when things don't go right it doesn't seem like it at the time.)

no one EVER knows EVERYTHING !!
and if they think they do, then they are an idiot !!

[DOOLEY]

hello Thomas,

ah................

abrupt, yes.

never had a scathing reply before, no.

shocked and offended, yes.

no need for the picture.
or that reply.


anyways,
back to the chase.

I understand now,
lost in google translation then I assume.....

originally I was using the circuit to drive an 8 ohm speaker,
putting a resistor between the emitter an the speaker would have limited
the maximum volume,
so I didn't put one in.

but yes an 8 ohm load driven from say 8v would theoretically take 1 amp,
suppose I could have put a 47 ohm in there to limit current to 74 ma,
for a 1.5w speaker this would have driven it at a safe 1.15w max.

it was never going to get that much drive from a 3904 with a 10k base resistor,
doing a quick calculation speaker was only ever going to see 55 mw at best.
and with 50% duty it was never going to blow the speaker away.......

ah well,
many apologies to all for not placing a load resistor there,
didn't think it would result in a ho down............

[Thomas]

I guess your Google translation from Google English to American is having problems, I don't care why or what you did, only that you think about what a human dilemma language is for all. I have found that what is scathing to one, is a poke in the ribs to another. Or as they say in my country "lighten up dude" Please do not take that as an assault, only good intent.
Thomas

[DOOLEY]

right oh,

so i'm in the wrong then..................

translation wasn't wrong when the name calling started,

and during the process of KT searching for a picture and hitting send
was also a translation error.....................

don't think so.

with all due respect to you Thomas,
i'm not having a go at you,
personally or otherwise:

translation can be a problem,
I agree.
but please stop defending others actions and making out me to be at fault here.

enough said.

can we all just get back to the normal,
all a bit wiser,
and where some of us think twice before even bothering to post here at all...................

[kt315]

emotions my friend. only emotions. I am too dummy and learn electronics every time of my life. and what?
I learn all my life and never said that I am guru.