Sam_sky

Thank you for your reply.. happy to follow any circuit that I can build One of the main challenge here in India.. these pedal cost even more.. all they might have is a op amp and 2 to resistors.. Kindly assist..! Sam Also will Cable Ferrites or ferrite bleed help?

I am currently using a Stratocaster Guitar to a Guitar processor to AMP (or direct PA).. I am getting a high frequency feedback - kindly see the attached picture.. Only when I use the acoustic guitar patch ...(for other patch I might not hear it - but its not a patch issue).. - I tried building a low pass filter to cut that frequency - with the attached CAP and RESISTOR value. - Unfortunately the overall tone gets very muddy and I needed your help cut the feedback issue yet have decent treble.. is it because of the cap or not sure why the before calculation does not work? kindly help..

Awesome..

Thank you... Yes - I tried bypassing and it sound fine.. (Think the preamp is messed up - might put a switch to alternate between preamp and direct in power amp in) Because the overdrive sound from preamp is nice to hear (Unsure if the preamp blow out soon).. ------------------- Audio Guru you are awesome.. This is not the first time you have helped me - previously you have helped with a project with TL072 - on board Guitar Preamp and came out with flying colors.. and I took that to a professional guitar guy and he failed after preparing 1000's PCB's with the same circuit. but I used a General PCB and came beautifully well & with your suggestions.. -------------------- Guess you can do lots of freelancing earn with all your suggestions .. I use my Excel automation on Fiverr dot com as a hobby and get decent money. Professionals like you could earn 1000K+ in a month within 3 to 4 months of experience Well I'm not advertising the freelancing site.. just telling.. Take care Sam

Actually I tried the a Cell phone headphones out thro this at very low volume .. still the same.. I will connect directly and update you and check the result.. Only concern I have is - because of this distortion, is it bad for the speaker or the AMP..? * without the preamp see if this occurs..

My bad it was LA4508.. I managed to sort out the issue.. but there are other problems which I would tell below.. Basically the power Amp seems to power up two channels separately - Right and left and it works fine. Isolated the issue onto the preamp.. but it proved to a issue with the input switch (or I think so).. sound ok now with the mind distortion.. ------------------------------------------------------------------------------------------------------------------------------------------------------------- There is one more issue from the beginning (even before I could dismantle) - the sound is getting distorted - this is not like it doing this on high volume.. more like a guitar over drive sound.. (Please note that the Amp was working fine with the clean sound with the same circuit previously). The preamp uses 3 transistor 547b and does not have any overdrive or distortion circuit.. - I need to check sound without the preamp check the quality of the sound.. - I have checked with one 4ohm speaker and a tweeter (connected in parallel) and without the tweeter - still the same My question.. 1. Why does this it distort - (it is like a nice over drive sound)..(sounds great when I play my guitar with distortion effect) - but the cleans notes are affected.. 2. If it is the preamp - what component should I check to avoid the clipping? (Bass and treble set to low and high - does not have an effect on distortion) Sam

Hi, I have a very old Amplifier (Stereo) powered by two LA4058 IC's as per the spec - it says it is a 100W Amp - has a circuit more or less like this http://fixmag.ru/download/1259351172_sp-011.pdfRefer Page number 5 for the circuitbut the difference in my circuit is that - it uses the same circuit twice meaning - I have the similar circuit with two LA4058 IC's Guess the POWER AMP with each IC is to power Right and Left channel's ---------> not sure - The power source is 13.6V AC transformer - Connects a 4 ohms speaker and 4 ohms tweeter - I use it for my guitar ( connected via a processor). Issue: Every thing was working well as desired - issue popped up after I decided to move the amp complete unit to a speaker box(like one unit where it will have Speaker and amp in same speaker box) - like a guitar amplifier setup.- When I connect the speaker to the Right channel - all I hear a distortion buzz.. ( increases when I increase the volume ) - when I connect the Speaker to the left Channel - I get a duh duh duh sound ( Think that is distortion but with lesser strength) ( increases when I increase the volume ) Trouble shooting done: 1. Checked for the earthing or common for the Transformer and power amp and wiring connections 2. When I disconnect my Pre amp from Power Amp. I get no sound from the speaker - unsure if the speaker getting the signal but When I power ON.. I dont hear or feel the Speaker cone move.. - Unsure if I can connect the CD player or guitar directly to the Power Amp to check the problem is with power Amp or Preamp. Also the LED for Both channels does not glow - Unsure why the noise is coming - basically the setup is not working Please help.. Sam