angelo2979
Well-known member
- Joined
- Nov 24, 2008
- Messages
- 74
Hello world,
I would like to share with everyone my experience with the Eden preampiifiers designed by Expat Audio. This is the second project I build, after a GSSL, and I'm very happy to contribute to the forum, maybe helping who can be interested to these little but smart babies. So, I'm going to give you some adivices, and then post some pictures and some sound samples, so that everybody can listen and judge.
But, first of all, I have to thank "Rochey", from Expat Audio, for having helped and greatly supported me with all the troubles I encountered during this project. Actually stupid problems, but still problems.
Anyways this project is very easy, and it will be even easier if you'll take care of my suggestions...
Here we go:
- About room: I have easily built 4 Edens in a 1U rack and I've used all the optional boards, that are the Ctrl boards (with the included pushbuttons) and the Front End input boards. Anyways, I think that maybe more experienced builders could stick 8 pres in 1U without too many problems. Not me though.
- If I'll ever build some of these again, I will consider putting the Ctrl and FE boards as near as possible, trying to reduce the lenght of the wires that connect them togheter...and so make the whole thing less messy. (but this means that you could not solder the xlr inputs directly to the FE boards)
- if you cannot (or don't want) to mount the pushbuttons directly to the Ctrl boards, but (unless you want to use your own switches) you decide to mount them indipendently, you can do like me: solder the buttons on breadboards, and fix these to the Front Panel. It works ok, but then you have to make jumpers to connect the pushbuttons to the ctrl boards.
- if you, like me, decide to go for the small phone charger solution to power up the relays on the FE boards (with 5v relays then), here is what I suggest you: DON'T USE THOSE NOKIA PHONE CHARGERS, as they really are not reliable. I found out that they have a higher output voltage, and that their current is not enough to power all that stuff, also considering eventual peaks in the signal. I have actually resolved all the problems I had just replacing the charger. So buy one that really outputs 5v, and at least 600mA.
- If you don't use isolated screws to fix the boards to the case, be sure of not pushing them to much as I experienced some bad contacts between one of the ctrl boards and the screws, causing the buttons to light madly and not properly switching. I don't actually know if it is a design problem or if it just was some bad soldering. I just know that I left the boards enough distanced and everything worked well.
- Be Sure that you are properly connecting your grounding system, and don't make confusion with all those Analog and Digital GNDs... maybe ask to Rochey for details
- If you are going to include the phantom power, I suggest you to do how Rochey suggested me: connect to ground two resistors higher then 100k, between the hot and cold signal inputs. This is going to reduce the phantom decay time to 30s. Without, it should take 5-10 minutes, so these resistors could be usefull if you have any ribbon mics...
- if you use phantom, be sure of connecting the DC blocking caps to the Eden inputs! You can use caps of any value higher then 10uf and 50v... Higher values preserve the low frequencies.. I used 22uf/63v, and I see they are common. Anyways, if you have time and will, you could experiment some switching circuit to bypass the caps while not using the phantom. I don't know if this could really improve the sound of a passive mic though.
- I think that's all! I'm going to post some pictures and sound samples, so stay tuned! ;D
I would like to share with everyone my experience with the Eden preampiifiers designed by Expat Audio. This is the second project I build, after a GSSL, and I'm very happy to contribute to the forum, maybe helping who can be interested to these little but smart babies. So, I'm going to give you some adivices, and then post some pictures and some sound samples, so that everybody can listen and judge.
But, first of all, I have to thank "Rochey", from Expat Audio, for having helped and greatly supported me with all the troubles I encountered during this project. Actually stupid problems, but still problems.
Anyways this project is very easy, and it will be even easier if you'll take care of my suggestions...
Here we go:
- About room: I have easily built 4 Edens in a 1U rack and I've used all the optional boards, that are the Ctrl boards (with the included pushbuttons) and the Front End input boards. Anyways, I think that maybe more experienced builders could stick 8 pres in 1U without too many problems. Not me though.
- If I'll ever build some of these again, I will consider putting the Ctrl and FE boards as near as possible, trying to reduce the lenght of the wires that connect them togheter...and so make the whole thing less messy. (but this means that you could not solder the xlr inputs directly to the FE boards)
- if you cannot (or don't want) to mount the pushbuttons directly to the Ctrl boards, but (unless you want to use your own switches) you decide to mount them indipendently, you can do like me: solder the buttons on breadboards, and fix these to the Front Panel. It works ok, but then you have to make jumpers to connect the pushbuttons to the ctrl boards.
- if you, like me, decide to go for the small phone charger solution to power up the relays on the FE boards (with 5v relays then), here is what I suggest you: DON'T USE THOSE NOKIA PHONE CHARGERS, as they really are not reliable. I found out that they have a higher output voltage, and that their current is not enough to power all that stuff, also considering eventual peaks in the signal. I have actually resolved all the problems I had just replacing the charger. So buy one that really outputs 5v, and at least 600mA.
- If you don't use isolated screws to fix the boards to the case, be sure of not pushing them to much as I experienced some bad contacts between one of the ctrl boards and the screws, causing the buttons to light madly and not properly switching. I don't actually know if it is a design problem or if it just was some bad soldering. I just know that I left the boards enough distanced and everything worked well.
- Be Sure that you are properly connecting your grounding system, and don't make confusion with all those Analog and Digital GNDs... maybe ask to Rochey for details
- If you are going to include the phantom power, I suggest you to do how Rochey suggested me: connect to ground two resistors higher then 100k, between the hot and cold signal inputs. This is going to reduce the phantom decay time to 30s. Without, it should take 5-10 minutes, so these resistors could be usefull if you have any ribbon mics...
- if you use phantom, be sure of connecting the DC blocking caps to the Eden inputs! You can use caps of any value higher then 10uf and 50v... Higher values preserve the low frequencies.. I used 22uf/63v, and I see they are common. Anyways, if you have time and will, you could experiment some switching circuit to bypass the caps while not using the phantom. I don't know if this could really improve the sound of a passive mic though.
- I think that's all! I'm going to post some pictures and sound samples, so stay tuned! ;D