Nice build qwertyl.
How do you find it compared to your F4?
Missed your post re stripping out one of the F4's
How do you find it compared to your F4?
Missed your post re stripping out one of the F4's
I prefer Aleph, it sounds warmer. F4 is a bit dry for me, but it has better control of low frequencies and I think it is more neutral/transparent. Aleph J has its own character.
Saying all that, I don't have a proper preamp for F4...
Try the F4 with a tube preamp. I prefer the Aleph series myself over the F4. Absolutely nothing wrong with the F4 and as we all know amplifier preference depends on the speakers one is using.
Very nice looking.
Very nice looking.
Thanks. I planned to build Impasse, but now I am thinking of BA-3. Also, Pearl 2 is in pipelane...
Yes, the speakers are very important. Mine are quite old and cheap Monitor Audio. They are going soon, but not sure what would be a good match for Aleph. I like ProAc Response D18, sensitivity not very high though...
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One thing I noticed is that my Aleph was getting really hot when testing it early with partly built chassis (no front panel, no top cover, no bottom cover), but now fully enclosed it is just getting pleasingly warm 🙂 Also, when heat rises bias is drifting down. Is that normal?
Thank you guys. Has anyone built a separate PSU for their Aleph/Firstwatt amps? I'm building my Aleph J now and I've ordered boards and parts for the F6. I'd like to build one PSU to be used for either amplifier. What connectors would you recommend between the PSU and amp--something by Neutrik?
Also, what special design considerations need to be kept in mind while laying out the amp and PSU chassis?
Ie, something like: keep the capacitors at the back of the enclosure to minimize DC cable runs, use shielded cable for all A/C cabling, keep power umbilical away from A/C and source cabling, keep power umbilical as short as possible, etc?
I built a single power supply for my F6 and AJ amps. I used the Neutrik speakon 4 pole connectors. I don't recall their amp rating be remember they were rated well above what was needed.
The umbilical is about 1.5 meters long, unshielded. I've done nothing special in the amps and the umbilical acts like the "r" in the crc filter.
The amps are dead quite and I'm planning any future amps to be run off this power supply.
The umbilical is about 1.5 meters long, unshielded. I've done nothing special in the amps and the umbilical acts like the "r" in the crc filter.
The amps are dead quite and I'm planning any future amps to be run off this power supply.
I used Neutrik Power con to connect my twin power cords, they are rated plenty high....speak on are for speaker hook up, I dont know how many amps they handle, but the web site will tell you.
Russellc
Hi Zen Mod,
Thank you very much for your advice for the grounding for my 6ch Alph J in one chassis project. I followed your advice, and the amp has absolutely zero hum and zero noise with 111dB sensitivity horn. I'll upload pictures soon!
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And there is no thump when power on, but a little at power off ONLY connected the amp to the transformer output preamp stage.
Here is the quick RMAA test result @ 25W. Looks great, doesn't it?
Green is DA/ AD direct loop, White is Aleph J with 8 ohm resistor load. (DA output is digitally trimmed to -12dB or so, so DA is actually +12dB better spec than this...)
I would like to say thank you to everyone here. This is my first DIY amp and without your help, I couldn't finish it.
Green is DA/ AD direct loop, White is Aleph J with 8 ohm resistor load. (DA output is digitally trimmed to -12dB or so, so DA is actually +12dB better spec than this...)
I would like to say thank you to everyone here. This is my first DIY amp and without your help, I couldn't finish it.
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Some pictures of 6ch Aleph J. 24"X 18"X 12", too heavy to carry myself. The amp is driving JBL DMS-1. 4 outs go to each woofers and 2 go to the compression drivers. The center big chokes are used for compression driver DC protection without phase shift at crossover range. The heatsinks are about as hot as my PassLab's Aleph 5.
I almost forgot to say the amp sounds absolutely wonderful.
Thank you, everyone!
I almost forgot to say the amp sounds absolutely wonderful.
Thank you, everyone!
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Wow, I thought putting 4 channel could already be overkill but you managed to put 6
Looks like HT build you got...
Welcome to FAB club...
Looks like HT build you got...
Welcome to FAB club...
Avel Lindberg transformers
I think these transformers are not the highest quality - they are buzzing a lot in my Aleph J. I have 2 of them, both 500VA, 2x18V, swapped between F4 and Aleph. They are Ok in F4, but very noisy in Aleph, probably due to non-symmetrical loading. Is there anything I can do to make them more quiet?
I think these transformers are not the highest quality - they are buzzing a lot in my Aleph J. I have 2 of them, both 500VA, 2x18V, swapped between F4 and Aleph. They are Ok in F4, but very noisy in Aleph, probably due to non-symmetrical loading. Is there anything I can do to make them more quiet?
I've used a number of Avel Lindberg transformers without any issues. That they work in your F4 but buzz in AJ sounds like something has changed. Why do you think the loading in an AJ is asymmetric? Could you now have DC on the mains or something shorted/low resistance to ground in this build?
To Quertyl: This was discussed elsewhere. In an Aleph J you need to have a separate full bridge rectifier for the positive rail coming from one pair of 18 VAC outputs and a separate full bridge for the negative rail from the second pair of 18 VAC outputs. The positive rail does have more load than the negative in an Aleph J. If you have a center tap, then you need to change something.