Thanks Brian,
I did all that, took the amp board off and had a close look, measured everything with multi meter , then I realised I hadn't swapped the speaker leads from the aleph so did that and that seems to have been the problem, all works fine now. Phew. What a relief.
So it's my turn to thank 6L6 for the excellent guide and everyone here who has helped me through my first really successful amp build.
I've been trying to find the parts in this enormous thread where 6L6 and others were discussing their preamp preferences.
Would it be possible to have a few ideas on that please to spare me reading the whole 300 pages?
I'd like to build a valve preamp and possibly another phono one too though this little Rega I'm using sounds fine. But until you hear something better you never really know and it's always possible.
Someone described the Aleph J as producing a holographic sound. I think that's true. I can listen to all the instruments in the band on most records I've sampled so far and I discovered one record that I can't listen to any more. Amazing.
And of course much gratitude to the guru Nelson Pass. A truly generous and brilliant man.
I did all that, took the amp board off and had a close look, measured everything with multi meter , then I realised I hadn't swapped the speaker leads from the aleph so did that and that seems to have been the problem, all works fine now. Phew. What a relief.
So it's my turn to thank 6L6 for the excellent guide and everyone here who has helped me through my first really successful amp build.
I've been trying to find the parts in this enormous thread where 6L6 and others were discussing their preamp preferences.
Would it be possible to have a few ideas on that please to spare me reading the whole 300 pages?
I'd like to build a valve preamp and possibly another phono one too though this little Rega I'm using sounds fine. But until you hear something better you never really know and it's always possible.
Someone described the Aleph J as producing a holographic sound. I think that's true. I can listen to all the instruments in the band on most records I've sampled so far and I discovered one record that I can't listen to any more. Amazing.
And of course much gratitude to the guru Nelson Pass. A truly generous and brilliant man.
Last edited:
Wot,
I have been keeping my eyes peeled and searched for pre amp recommendations as well.
Seems I remember 6L6 being high on the Pass BA-3 as a pre amp, but it's solid state. Perhaps a tube buffer could be incorporated by someone more electronically astute than myself.
I too have some recordings that just don't cut it since I went to higher resolution DAC/Amp/Speakers that only sounded a bit flat and lifeless before.
One music piece I need to make sure you know about.
"Maggot Brain" by Funkadelic.
Off putting title, but some of the most amazing electric guitar work ever.
If you have it, you know. If you get it, prepare to be impressed, go Wot (Wov?) on the volume and holograph that.
I have been keeping my eyes peeled and searched for pre amp recommendations as well.
Seems I remember 6L6 being high on the Pass BA-3 as a pre amp, but it's solid state. Perhaps a tube buffer could be incorporated by someone more electronically astute than myself.
I too have some recordings that just don't cut it since I went to higher resolution DAC/Amp/Speakers that only sounded a bit flat and lifeless before.
One music piece I need to make sure you know about.
"Maggot Brain" by Funkadelic.
Off putting title, but some of the most amazing electric guitar work ever.
If you have it, you know. If you get it, prepare to be impressed, go Wot (Wov?) on the volume and holograph that.
I am running a tubecad Aikido preamp right now although I am thinking of changing to a balanced preamp. My Aleph J and F5 are both setup to take balanced inputs. My DAC is also diy a DDDac 1794 which is also capable of balanced output. Listening to Dave Brubeck -Time Changes right now through the ACA. Nice cymbals. The early stereo recordings often had instruments hard left or right which is a different sound than the typical modern recording. Since so much classic Jazz was recorded in that era I find myself listening to that recording style quite often.
Your observation interests me.
Does this hard left or right tendency extend to late 60's/early 70's rock?
Although in my case it's everything, not just instruments.
Assumed my ears to be the reason I always seem to think I need to bias to the left.
Pre amps coming to the store, eh?
May have to postpone my plan to head up the ladder from the ACA's on the amp end of things.
Here are some pics now that my Aleph J is running.
Yet to tie up some wires, replace that LED that's out on the power board and make the lid with millions of holes. I think I still got that LED the wrong way round despite everything.
Probably a bad time now but a few holes in the base will no doubt help as well.
It's running at max 48C localized to the mosfet connection areas.
Average is round 45C.
Aren't these new infrared thermometers amazing?
Yet to tie up some wires, replace that LED that's out on the power board and make the lid with millions of holes. I think I still got that LED the wrong way round despite everything.
Probably a bad time now but a few holes in the base will no doubt help as well.
It's running at max 48C localized to the mosfet connection areas.
Average is round 45C.
Aren't these new infrared thermometers amazing?
Last edited:
Quite new to this amp building, so I'll ask.
Seems a reasonable assumption that the MOSFET connection would be the hot spot; If so, it also seems that a 3deg difference from the hot spot to the area average would indicate adequate heat sink and thermal transfer.
Are my guesstimations close?
Yeah, the infra red, non contact thermometers are the berries.
No workshop should be without one for no more than they cost.
Seems a reasonable assumption that the MOSFET connection would be the hot spot; If so, it also seems that a 3deg difference from the hot spot to the area average would indicate adequate heat sink and thermal transfer.
Are my guesstimations close?
Yeah, the infra red, non contact thermometers are the berries.
No workshop should be without one for no more than they cost.
Aleph J is single ended class A only but with the Aleph twist that allows it to produce more power than a conventional class A amp for a given bias level. It does not transition to AB at higher powers like an F5 push pull amp. I used an Antek 20v 400va transformer and did not use any soft start or thermistors and everything is fine. I am using a CLC Filter so it’s not quite the same as a standard first watt supply.
I have mine at 55 degrees Celsius with 420 bias in a 4U chassis. I’m on the edge of being too hot for my sinks and that’s listening sessions for 5-6 hrs of listening. Papa posted a comment on temp in relation to how long you can leave your hand on the sinks. It’s in this thread somewhere.
Pass DIY Addict
Joined 2000
Paid Member
Some level of air circulation through the amp will allow parts inside to last longer... Break out the drill and poke some holes in that lower plate. Perhaps you have a local machine shop that can cut some nice slots in the top plate for you, otherwise use your drill here too. Draw some lines with a pencil and use your drill press so you get nice, regular holes, then sand the top off a little with some fine paper to give it a "brushed" look. You can wet sand up to 400-600 grit and it will look pretty nice.
Yeah Eric, At first I was going to get it laser cut but found out nobody round here cuts aluminium with a laser.
Then I was fantasizing about making a lute rose on the top.
This is one of my faves.
But that's just silly. So I just need to comeup with a reasonable design that looks right and lets enough air through.
I'll get out the pencil. All this can be cut with a jeweller's saw in any shape you like.
Then I was fantasizing about making a lute rose on the top.
This is one of my faves.
But that's just silly. So I just need to comeup with a reasonable design that looks right and lets enough air through.
I'll get out the pencil. All this can be cut with a jeweller's saw in any shape you like.