amz jfet buffer "quieter" than i had imagined

[petey twofinger]

i built one of 2 of these recently , the first one seemed to boost the Db output a considerable ammount . the second , well when A/B testing it i didnt notice ANY volume boost . the circuit seems to be working , when i disconect the power it cuts out . i also cut in a switch for 2 different input cap values , a .1 uf and a .0047 uf . cant tell much difference between those either .



http://www.muzique.com/schem/eagle.htm

i had thought of putting a 100k pot on the out put so  not only could i use it as a buffer but maybe a booster too . the first one i made seemed to boost a lot of DB's  .

i used the same part values , and j201's in both , except the 10m resistor on the front end was not needed in the first circuit (that one is always on in an amp .

would a mpf102 give me more gain ? could i simply swap rthe j201 out for a mpf102 ?

should i built an lpb1 instead ? would an lpb1 (or different buffer circuit) accomplish the same effect with the volume set lower . i have a chassis all painted and drilled ... a tiny one , 1509b or whatever . i do not have any op amps yet but i am almost thinking i would like to hear something . i am testing it on a mini amp , a stella , with nothing else , humbuckers

thanks !!.

[PRR]

> the first one seemed to boost the Db output a considerable ammount

It can't. The gain is slightly less than unity. With different JFETs it may be 0.85 or 0.95. Not enough difference to matter.

Somehow it is not wired the way you are telling it.

[petey twofinger]

the first one is in a powered subwoofer enclosure that has a hanna montanna pcb with an echo circuit , the buffer goes to the mic input , that circuit has an lm386 that feeds the tda 2008 chip amp in this sub woofer cab i got .  when i was testing it i honestly seem to remember a/b'ing and hearing a considerable "boost" in volume . that circuit is running all the time and boxed up so i guess i was wrong or something was up .

so even if i try different j201's it will still not get much louder cause this circuit doesnt exede unity gain ?
if that is correct i should think about a different circuit .

unless having a buffer like this is a good idea ... not sure .

at that point i would make a nother booster , like an lpb1 or a mu amp(?) fetzer valve (bassman?) sho , or ? (klon boost , amz mini )

i really have no idea .

i was hoping for some recommendations or advice . is there a small / simple circuit that will do what i want (buffer AND booster depending on where you set the output pot) or is this a bad idea , not sure at all . i THINK i like the idea of jfets over opamps , but only cause i read that on a site and i dont have any opamps yet , just lm286 .

it seems to me , if i could achieve both , it would be more economical all the way around , but i really dont know where the booster or buffer would ideally go in the chain !! would i benifit from having seperate buffer and booster pedals ? if not than it seems a no brainer , i just need a boost that will fit in this chassis. maybe i could have a switching cap for tone .

thanks for your patience , i did a rehouse , this is my first "from scratch " build so i am very very green . the thing with the back injury , well i cant work much , lately i have been in bad shape so i really appreciate any help / advice , klon boost , amz mini

[PRR]

> a hanna montanna pcb with an echo circuit , the buffer goes to the mic input ,

OK. The mike input is a HEAVY load for guitar. Probably cut your signal down to a third. Inserting the buffer got you back to 90%. 33% to 90% is a big "boost"; actually a lesser loss.

[petey twofinger]

what would be a smarter "front end" for the hanna montanna circuit , i have 4 of those and i was thinking of hacking one into a pedal .

thanks .