hey all

finally i have decided that i will go with lm1875. because i have realized that 20-25 watt is enough for me for my efficient guitar speaker (eminence governor) having spl of102.

now i am bit confused with which schematic to adopt for my guitar amp.(+vcc -vee) type
1. do i require any buffer between the preamp and power amp.

2. for guitar amp what should be the uF value for the filter capacitor.

3. i have decided to run it through 18 0 -18 ct transformer. for moderate efficiency what should be the ampere rating of the transformer.

4. many one are suggesting to use good grounding techniques for minimal noise and hum.. any advise ?

5. what is zobel network? do i have to adopt this for good. where i have to add this in the ckt?

6. what type of delay ckt i can add to minimize on pop sound
(plz see the attachment. this is what i have found by googling) .

7. do i have to attach the earth wire (green ) with the zero voltage pin for safety?

additionally if some one to share his opinion on lm1875 or any thing related to amp building then plz write here..

let me have those answers plz and i will start working on the project. during the time if i have any problem i will post here to get feedback from gurus..

thanks

thank you joecool...

how do  u print pcb...

i am trying with the copper clad board but the ironing the pcb image on the copper clad is not transferring(keeping the iron at full temparature)........

thank u again for your reply

thanks for the reply.

please reply me for the following question......



i am going to add sansamp gt2 clone in the preamp. does it requires to go through any intermediate
circuitry or directly feed into power amp?

another question....
3886 has a 10k pot prior to the on inv. input. in ggg.com it is mentioned as a 10k trimmer.
should i use it as a pot or trimmer with a fixed value or can eliminate since sansamp circuit has its own
output level control.....

i will place bit by bit information here as soon as i start the work...

thanks

hello fahey and joecool
thanks to both of you for your prompt reply. acually 18v+18v transformer is not available in india....
instead can i use center tap transformer with 18 0 -18 rating..........so through bridge rectifier i can get +-25v (around)...shown in the picture....
what are its drawback.........compared to 18v+18v
kindly reply

joecool please elaborate the transformer rating plz

fahey thanks for  the reply...
plz suggest transformer rating for max 30w +-18v

is dual rail transformer 18v+18v means center tap +18 0 -18?

i am going to add sansamp gt2 clone in the preamp. does it requires to go through any intermediate
circuitry or directly feed into power amp?

another question....
3886 has a 10k pot prior to the onon inv. input. in ggg.com it is mentioned as a 10k trimmer.
should i use it as a pot or trimmer with a fixed value or can eliminate since sansamp circuit has its own
output level control.....

little worried since its my first power amp project.....need you...........

Hi everyone

actually i want to build a versatile guitar amplifier using eminence guvnor 75w speaker.
i want to build around max 30-35 w.
for the power section what chip you suggest?(like 3886 3875 etc ).
can u please refer any good schematic of the power supply?

i have found lots of crying for both 3886 and 3875 in different perspectives.
but you guys please suggest me in terms of guitar amplifier?

do you think 3886 /3875 are more than enough for 30/35w or the TDA chips will do?
what is the difference in producing quality sound for LM3886 types vs TDA 2030 types chips?(in terms of guitar power amp).

or instead i should go with discrete solid state(mk ii)??

please suggest your valuable experience from your DIY journey.
thanks

hi everyone,

For 30-40w guitar power amplifier which chip you will recommend concerning power rating and mostly on the sound quality ( warmth in the sound is preferable as to emulate tubes as much as posssible ). please provide the reasons from the experience that u have gathered in your DIY journey........

thank u guys!!!!

hello

you have mentioned in one thread that you have worked with trademark 60. can u post me the power section schematic,details,psu details of trademark 60/30. this is a killer ss amp. i am not going to ask u for the preamp cause i know this is very complicated.

thanks

does the amplifier Dissipated same amount of power all the time or it is dependent on the gain and volume control?


in terms of quality which one is better?
1. chip amp
2. amp with discrete elements

thanks for the reply

thanks for the reply sir.

sir i know you are experienced enough. between 30-50 watt can u upload me a good power section schematic which u consider the best
(as per sound, reliability and durability)

my last question to u as some one told me, that if i use 30 watt power amp for 75 watt speaker then it will never break out and most of the best sound comes when the speaker breaks. is that true?( may be a 'subjective' type question)


is it the case that the power dissipation is a factor of output volume or gain or it consume near about 50 watt every time irrespective of the volume and gain dial(considering lm3886).


another question i want to ask.

if you are given to give marks on the several key parts on the solid state amp(pre amp,power amp,wood,speaker) then how much percentages you will give to these sections?
thanks

hello


i have decided to build a 30watt(maximum) solid state guitar amp.
i will use sansamp gt2 as the preamp section (as i am trying to make a clone of the tech21 trademark 30 SS) .probably i will add a reverb effect.

now i need the schematic of a good power section(for 30 watt max).
i have decided that i will use eminence governor (75 watts 12") speaker for
my project.

is this a right speaker to use it for a 30 watt amp??

you guys are experienced in the cabinet construction. can u help me with some doccuments on the requirements and procedure of cabinet construction(open back is preferable).

please help me please please!!!!!!!!