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Gain on Jason supplied kits
Hi
With the supplied parts kits, what is the gain on each of the mini Aleph, and the Aleph30 (I have some of each), or how could I calculate it? (It's to determine the need for a preamp with gain x, if using a tuner as well as CD).
By changing what parts, can gain be boosted, to avoid the need for a preamp?
Thanks
Hi
With the supplied parts kits, what is the gain on each of the mini Aleph, and the Aleph30 (I have some of each), or how could I calculate it? (It's to determine the need for a preamp with gain x, if using a tuner as well as CD).
By changing what parts, can gain be boosted, to avoid the need for a preamp?
Thanks
Banned
Joined 2002
Banned
Joined 2002
rabstg said:
I can only think it would be due to break in time. the blue mini a's SMD have tons of hours on them..
here is the pictures.
http://jleaman.ath.cx/minia
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Joined 2002
BrianGT said:
There both running right now.. bot new ones that is.. id lke to know what is dferent about the input tho.. the smd ones are much more sencitive than these ones..
I have been running the blue ones in passive mode these new ones are on the quiet side..
right now they are now workint at 20V rails.. not 15..
jleaman said:
The SMD boards don't have the extra circuitry on the input, which was introduced with the A30 and A60. Read the service manuals and compare to the Mini-Aleph manual. The SMD boards also don't support balanced inputs. Think of them as version0 of the Mini-A boards, except with SMD parts.
You can also assemble the new boards in the same configuration as the SMD boards.
--
Brian
BrianGT said:
Hi Brian,
How long would you reccon is required for break-in?
Had my mini finnished last week and liked the sound from the first minute!
Also have some photo's for your galery of my mini. Do I use your normal mail address?
I used 23V rails and 1,3A bias. This allows to crank-out about 20W of power @7Ohm.
This dissipates about 30W per fet and found that the IRFP052 can handle a higher junction temp and gives a bit more safety than the 044 0r 240.
The result is a mono block that way's about 4 kg and measures 18Cm wide, 12Cm high and 20Cm deep.
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Joined 2002
jleaman...I measured the temperature carefully, and estimated the junction temp to be close to 100 degC.
At these temperatures there isn't much room for error!
I took a lot of precaution when mounting the fet's. In my amp the fets are mounted on am aluminium tube of 5 x 10Cm (4mm thick)
A 0,4 deg/W sink mounted on eiter side.
the sinks are 47degC after 1 hour of operation. The alu tube is about 55degC the mounting surface of the fet 65degC.
At 0,8degC per watt Rjc this is 90degC for the junction of the fet.
If you look at the IRF derating specs, you will find that my operating point only has a margine of 15W dissipation or 20deg margine in junction temp.
Now it becomes really clear why Nelson is using the world supply of fets parralell in his amps!
At these temperatures there isn't much room for error!
I took a lot of precaution when mounting the fet's. In my amp the fets are mounted on am aluminium tube of 5 x 10Cm (4mm thick)
A 0,4 deg/W sink mounted on eiter side.
the sinks are 47degC after 1 hour of operation. The alu tube is about 55degC the mounting surface of the fet 65degC.
At 0,8degC per watt Rjc this is 90degC for the junction of the fet.
If you look at the IRF derating specs, you will find that my operating point only has a margine of 15W dissipation or 20deg margine in junction temp.
Now it becomes really clear why Nelson is using the world supply of fets parralell in his amps!
Banned
Joined 2002
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