Please any advice is welcome.
So i have started building a preamplifier so i can use it for testing purposes of some final amps i wanna build in the future. I dont have the possibility of listening to many preamps as all my systems were integrated pre amp and final amp..this is my first pre amp construction,
So i bought two kits by a Greek company named Smartkit www.smartkit.gr
A preamp kit that they call : Audiophile Preamp class A and the recomended power supply called: Audiophile Power Supply +- 15v.. The transformer used will be a 100Va 2x18v torroidal.
I give you the schematics of both the preamp and the psu including the partlist (some are in Greek..sorrryy..)
Any improvement is welcome of course before i start building..So if you want to comment please feel free! I will post some photos soon..i am now in the proccess of choosing what casing to buy.
Preamp Schematic:
Preamp Partlist:
PSU Schematics:
PSU Partlist:
So i have started building a preamplifier so i can use it for testing purposes of some final amps i wanna build in the future. I dont have the possibility of listening to many preamps as all my systems were integrated pre amp and final amp..this is my first pre amp construction,
So i bought two kits by a Greek company named Smartkit www.smartkit.gr
A preamp kit that they call : Audiophile Preamp class A and the recomended power supply called: Audiophile Power Supply +- 15v.. The transformer used will be a 100Va 2x18v torroidal.
I give you the schematics of both the preamp and the psu including the partlist (some are in Greek..sorrryy..)
Any improvement is welcome of course before i start building..So if you want to comment please feel free! I will post some photos soon..i am now in the proccess of choosing what casing to buy.
Preamp Schematic:
Preamp Partlist:
PSU Schematics:
PSU Partlist:
Hello ! "Smart" thing would be to eliminate first stage and go directly to C7 , unless you need that buffer to listen while you record ...Then , it seems that it is a little amplifier , with those beefy BD139-140 at the output , it should be able to drive long cables or in difficult settings . The audiophile rank of the PSU is just gained by adding RC snubbers at the diodes . The whole thing - a pre - could have been done with just an IC ,one pot , 4 resistor , 4 capacitors + 2 for compensation YMHO.
Also the supply ... 100 W it is an amplifier !
Also the supply ... 100 W it is an amplifier !
I also support picowallspeaker's suggestion. The obvious source of improvement will be to replace the 5534s, which were really great 30 years ago with something slightly more contemporary. It is really a matter of personal choice, so hopefully you have a drawer full of opamps like the rest of us 
Well i dont have any opamps around simply because i ve done in my life very few constructions, maybe 3-4 amps and thats all! So i dont have the experience to know which opamp is better..thars why i need your suggestions.if i change the opamp, it is done simply by changing the chip or do i need any extra mods? That what i want from the preamp is to be quiet, melodic and able to drive any final amp setup..
Hello again . I also support the "less is best" way,so you can omit first stage and keep the rest . A good add-on is to have two potentiometers , or stepped attenuators , to control each channel independently. Also the power supply has too many diodes for my taste...
If you keep the tracks and cables (also unshielded) far from the transformer , you 'd probably have a quiet pre.
If you keep the tracks and cables (also unshielded) far from the transformer , you 'd probably have a quiet pre.
also you recomend inputing the signal right before caps 7 and 57 right?..i may try that.sounds good!..i will also try to change these two caps with much better quality ones as i have some spares.
My friends do you know any online store selling good quality parts as good quality caps,resistors etc?..
My friends do you know any online store selling good quality parts as good quality caps,resistors etc?..
dear sifis ....we meet ...again ...
fanos in athens can supply you with alps pots 210-3828.748.if they dont have the specific model they will get it for you .....
spare a moment and listen to a couple of things please ....
there is a few things that are related to reference .... meaning that you may not learn to listen from a very good preamplifier
what i am trying to say is that you need to create a reference before everything else reference is created strictly by one cd ( not a source juast a disc ) of your favourite music , one cd player of any quality , one amplifier of any quality , and a pair of speakers of your choise ....
After that the only thing you nedd is to listen to this cd a gozillion of times if possible you nedd to know every litle small detail , every lilte small fragment of music , every lyric , every vocal ....in a few words everything .....
After that you will realize that any preamplifier and specificly this smart will sound much worst than a simple potentiometer between your cd player and your amplifier ....
to create a reference you dont need to have state of the art equipment ....you simply need to evaluate what you allready have .....then after that and alwayw with knowledge of what you listen you will be able to evaluate a new added preamp in the system , another pair of speakers , anther amp and goes on ....
if you expect to learn from smartkit products εισαι μακρυα νυχτωμενος φιλε μου ....
excuse my greek and my tone which as most forum memebrs know is mostly on the fun side no hard feelings for anyone
( nothing against smart kit products also ...old designs , working , but designs are made versus cost and material inside is most of the time cheapest available )
fanos in athens can supply you with alps pots 210-3828.748.if they dont have the specific model they will get it for you .....
spare a moment and listen to a couple of things please ....
there is a few things that are related to reference .... meaning that you may not learn to listen from a very good preamplifier
what i am trying to say is that you need to create a reference before everything else reference is created strictly by one cd ( not a source juast a disc ) of your favourite music , one cd player of any quality , one amplifier of any quality , and a pair of speakers of your choise ....
After that the only thing you nedd is to listen to this cd a gozillion of times if possible you nedd to know every litle small detail , every lilte small fragment of music , every lyric , every vocal ....in a few words everything .....
After that you will realize that any preamplifier and specificly this smart will sound much worst than a simple potentiometer between your cd player and your amplifier ....
to create a reference you dont need to have state of the art equipment ....you simply need to evaluate what you allready have .....then after that and alwayw with knowledge of what you listen you will be able to evaluate a new added preamp in the system , another pair of speakers , anther amp and goes on ....
if you expect to learn from smartkit products εισαι μακρυα νυχτωμενος φιλε μου ....
excuse my greek and my tone which as most forum memebrs know is mostly on the fun side no hard feelings for anyone
( nothing against smart kit products also ...old designs , working , but designs are made versus cost and material inside is most of the time cheapest available )
ah my friend i TOTALY understand you trust me. My problem is lack of knowledge and lack of time to study and read.Also i am so stressed in my life that even when i try to learn something new i just find it too hard...the reason i am building this preamp is just to know that i builted it and also in order to be able to test some prof final amps that i try to repair with my poor kowledge.Cheap professional amps that some people gave it to me for free and i try to repair.. i just want to build something that at least in theory is as good as i can build. currently i am listening to a T-amp using the Tripath 2020 EVERYDAY all the day. firstly using a switching supply,afterwards i builted a 12v 100va supply and i saw great difference..my quest is continouing as days passby...next step is to use in the same setup the Gainclone i try to finish weeks now, gainclone was bought from Audiosector... The preamp is going to be used for testing reasons.. to see if it sounds better or not etc...by the way my reference is some selections of songs of Giannis Kotsiras, Xatzis and Manu Chao...thats why i loooove warm-alive vocals...thanks for the advice my friend!i accept every advice...
Hi, If you want to try an alternative opamp a OPA134 would probably be suitable. It doesn't require the compensation capacitor from pin 8 to pin 5. But since pin 5 is not connected in a OPA134 it will not cause a problem if you leave it in.
It appears that the opamps in this design are biased into class A operation by a current mirror on the output. This may lead to the opamp running hot and you should check this if you change to a OPA134 as its characteristics will be different to a NE5534.
Having a buffer before the volume pot can sound better in some systems depending on the output impedance of your source so don't assume that bypassing the first stage will definately sound better.
Regards,
Andrew
It appears that the opamps in this design are biased into class A operation by a current mirror on the output. This may lead to the opamp running hot and you should check this if you change to a OPA134 as its characteristics will be different to a NE5534.
Having a buffer before the volume pot can sound better in some systems depending on the output impedance of your source so don't assume that bypassing the first stage will definately sound better.
Regards,
Andrew
I will try your advices guys... I also decided to integeate a dac in the preamp giving to my pream much more connection possibilities! I ll have a look in ebay.. I want both optical- spdif and usb connection.... I ve seen some interesting dacs... That what makes me sad is that i havent received my box yet to put the pre amp in...
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