Aleph 30 going on..

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I am currently idle-testing my amp with no load and no signal attached.

Power supply comes from a 2x22 Vac transformer (500 VA), primary capacitors (20 mF per rail), then a R-C for each channel (and rail) (165 mOhm - 30 mF).

Both rails are at about 30V dc, which is quite high for a Aleph 30 but since my heatsinks are big enough I don't care.

After a hour the thermistor I use for inrush protection settled at about 72 °C, while the heatsinks are slightly different but at least 20 degrees below.

I noticed that the "signal" mosfets get quite hot: is a small heatsink mandatory or they can be avoided?

for now.. that's all folks!

Cheers

Andrea
 
At last.. it is (almost) finished!!

Here are some photos of this little monster.. upper and back plate are made of sanded aluminium, the light from the pushbutton is actually blue (even if it doesn't seem...)
 

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First "serious" listening tests

Last evening I came to a friend's house bringing a heavy present, my (at last) completely re-wired Aleph to perform a listening test.

Speakers were B&W DM604, Preamplifier Yamaha MX-1000 (with on-board dac), CD player was actually a DVD player (digitally connected to the preamp).
Room quite large and with only few furniture pieces, so quite reflective.

The other amp was the companion of the MX-1000 , quite unfair as a comparison because of the great power difference. (This one puts > 500W as I was told).

After a evening made testing all three (the fourth was there only to drink!!) agreed that the sound was very good, especially in the mid-high range, lacking perhaps some control in the bass region.
The low impedance of the speakers didn't help at all, however the results were satisfying to adequate SPL levels, especially with non-synthetized music, voices and instruments seemed very natural.
Only some problems at higher volumes with CDs like "The Division Bell" but the great presence of bass frequencies (and the power required to play them) probably exceeded the available power of the amp.

In conclusion... I'm pleased, but I'd like to test it in another environment, with higher-impedance speakers and a smaller room.

To be continued...

Andrea
 
Since I don't have any balanced equipment I didn't even provide my Aleph with balanced connection.. :dead: but I have discovered that a friend owns a balanced tube preamp (and wants to sell it!), so I'll afford the expense of 2 XLR connectors shortly..😉

BTW if you look ath the thread where BLS PCB group purchase is discussed you can notice I had your same idea.
I'd like to build myself the preamp also, but I'd also like the remote control and the features that a commercial preamp offers.

In your opinion is a good idea to use the BLS after a regular preamp only as unbal-to-bal converter?

Cheers

Andrea
 
Andypairo said:


In your opinion is a good idea to use the BLS after a regular preamp only as unbal-to-bal converter?


It may be a good idea but you will need a pot at the output of the BLS to trow away some gain (and avoid noise) .

I would use it as a preamplifier/converter and find a remote-controlled-motorized pot for its inputs.


😎
 
stefanobilliani said:


It may be a good idea but you will need a pot at the output of the BLS to trow away some gain (and avoid noise) .

I would use it as a preamplifier/converter and find a remote-controlled-motorized pot for its inputs.


😎


Yes, but where WAF rules you also have to make things good-looking, and if for a power amp it is not a great problem for a preamp is a pain! Unless you can suggest me a suitable case to fit my BLS into....

Cheers

Andrea
 
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