A while ago a friend started to play aroud with Eagle and producing ideas for different board with the thought to make some project suitable for beginners and thus being easy to builld, no exotic parts (if you don't want to) and tested. "Fine" I thought, you play around whith that. Just don't drag me into the design because I had lost the interest at that point. So, I saw some posts but didn't pay them that much attention. Instead I produced a casing to house three of my five completed projects, the BOZ by Nelson Pass, Peter Daniels DAC and a Bugle RIAA from Hagtech. The casing got completed and I was/am very satisfied with it but my three main parts didn't like being moved from their other casings so they started to humm and buzz or just shut down, as in the DACs case.
So. The friend posted me a PCB for one of the projects, a OP-based Preamp designaded SOAP (Simple OpAmp Pre) and I put it in one of my drawers since I didn't feel like building anything. But I got fed up with chasing humm so I checked my partsbin and saw that I had all components needed for the SOAP and last night I started out by just soldering some resistors in place. One thing led to another and this morning all components where placed and soldered. Some parts where missing but the could be found in the pre I was using at the moment. So I decided to remove it and place the SOAP there instead and do some light testing. And thats where I am now.
I guess that I should post some pictures now that I have rambled on for this long. Here is one of the plain board, it measures approx 50x100mm (thats roughly 2x4 inch)
So. The friend posted me a PCB for one of the projects, a OP-based Preamp designaded SOAP (Simple OpAmp Pre) and I put it in one of my drawers since I didn't feel like building anything. But I got fed up with chasing humm so I checked my partsbin and saw that I had all components needed for the SOAP and last night I started out by just soldering some resistors in place. One thing led to another and this morning all components where placed and soldered. Some parts where missing but the could be found in the pre I was using at the moment. So I decided to remove it and place the SOAP there instead and do some light testing. And thats where I am now.
I guess that I should post some pictures now that I have rambled on for this long. Here is one of the plain board, it measures approx 50x100mm (thats roughly 2x4 inch)
Attachments
I wanted to have a transformer placed on the board but since it didn't come with that possibility I sawed out a piece of board, soldered the transformer and a fuseholder to it and screwed it to the SOAP-board. The result isn't that esteticly pleasing but it works for me. I placed a pair of cylidrical caps on the output but didn't like the way it looked so I later removed them (black-yellow in the picture).
Attachments
Thanx kmj !
It looks great, Could we get a picture of your chassi installation as well ? 🙂
Thanx
/JZ
It looks great, Could we get a picture of your chassi installation as well ? 🙂
Thanx
/JZ
yep, more pictures and rambling to come. Got other things to do first thou.
(for those who missed it, the above poster it the friend mentioned in the earlier posts)
(for those who missed it, the above poster it the friend mentioned in the earlier posts)
Well, there seems to be a lack of intrest but lets round it up anyway.
The pros and Cons
Cons: Some minor point regarding layout. None of these poses any problem at all, they are just minor things.
*If the length of JP3 that connects the earth of the PSU and that of the amp is shortened then you can use a piece of the cut of legs of a diode or similar instead of i wire.
*By changing place of the input and output caps it will be easier to switch OP if you want to.
*I want an onboard transformer 😀
Pros:
*The price! Compared to my BOZ (which I build REALLY cheap) I built the entire SOAP for less than what I payed for only the PSU-caps of the BOZ.
*Physicly small.
*Easy to build. Read, place, solder and you're done.
*No fuzz, no humm, no cracking.
*Dead quiet background and good bass and sound in general.
Ok, it is not as good as my BOZ, it lacks some of the midrange compared to it so the music feels a bit more alive with the BOZ, I do however like the bass more in the SOAP, I can't put my finger on it but I feel that there are a bit more detail and punch in it. I will stick with the SOAP since I find it a good sounding Pre-amp which fits my system and tast in music.
My system is as follows.
Sources:
Pro-ject 6.9 turntable w. Benz micro E2 gold pickup
Advanced acoustic MCD-203 CD-player
Pre-amp
SOAP
Hagtechs Bugle RIAA
Poweramp
Greg Balls GB150 (aka the SKA, simple killer amp)
Speakers
Troels Gravesens C17 HES.
The pros and Cons
Cons: Some minor point regarding layout. None of these poses any problem at all, they are just minor things.
*If the length of JP3 that connects the earth of the PSU and that of the amp is shortened then you can use a piece of the cut of legs of a diode or similar instead of i wire.
*By changing place of the input and output caps it will be easier to switch OP if you want to.
*I want an onboard transformer 😀
Pros:
*The price! Compared to my BOZ (which I build REALLY cheap) I built the entire SOAP for less than what I payed for only the PSU-caps of the BOZ.
*Physicly small.
*Easy to build. Read, place, solder and you're done.
*No fuzz, no humm, no cracking.
*Dead quiet background and good bass and sound in general.
Ok, it is not as good as my BOZ, it lacks some of the midrange compared to it so the music feels a bit more alive with the BOZ, I do however like the bass more in the SOAP, I can't put my finger on it but I feel that there are a bit more detail and punch in it. I will stick with the SOAP since I find it a good sounding Pre-amp which fits my system and tast in music.
My system is as follows.
Sources:
Pro-ject 6.9 turntable w. Benz micro E2 gold pickup
Advanced acoustic MCD-203 CD-player
Pre-amp
SOAP
Hagtechs Bugle RIAA
Poweramp
Greg Balls GB150 (aka the SKA, simple killer amp)
Speakers
Troels Gravesens C17 HES.
kmj said:
For more midrange,have you tried a small cap between the supply pins (+ to -).100nF is a good starting point.
What op amp are you using ?
I'm using OP2134 and I have 100nF between each rail and ground but not directly between the rails. Perhaps I sound try to add one there too?
Oh, straight at the pins or can the cap be placed a bit away from the pins?
Oh, straight at the pins or can the cap be placed a bit away from the pins?
kmj said:
I think it is better to put it as close the pins as possible.Under the circuit board is a good an logical place for a small poly cap,soldered to the pins of the socket.
Or soldered on top of the chip,directly to it's legs.I have done it this way.
Well, adding that cap ruined the whole thing. It works MUCH better without it. And after listening for a few days I am more satisfied with it 🙂
kmj said:
Yep sometimes it works and sometimes doesn't.
In my heaphone amp it was the "thing"(220nF).While my preamp/tonecontroll was way better without it.
kmj said:
Hi Kmj
I like your case...
If you didn't make the case yourself, may I ask where you purchased it?
Thanks
Richard
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