I have a classic Exposure XVll preamp that has an unusually high gain structure than the average preamp which makes it a difficult match for most amps. Do you think I will have any issues with matching it with the ACA that I would like to build?
I tried using the Exposure with a Luxman L-58a as the power amplifier (it has main in's) and I gotta a loud hiss and weird noise on first start up.
I tried using the Exposure with a Luxman L-58a as the power amplifier (it has main in's) and I gotta a loud hiss and weird noise on first start up.
Enochrome - yes, a quick look at the specs of your preamp shows it to be a monster! The F4 would be a perfect amp. As Variac says, it (the F4) has no gain of it's own, and your preamp look like it should be able to drive it very well!
The F4, BTW, is an utterly fantastic sounding amplifier.
The F4, BTW, is an utterly fantastic sounding amplifier.
Hi
Heres some rules I learned as an apprentice.
Mustly from Martin-Marietta`s "HANDBOOK OF WORKMANSHIP" (rocket science !)
All signal or DC carrying wires should be twisted hard/tight.(use a drill and a vice to twist)
+V,-V,0 V should be braided in hand,again tight.
All to minimize noise coming out from or into the wires.
And yes,it looks nice to.
Connect all 0V to the same point.(star)
If you are using screened cable for input and having hum,try disconecting the screen at one end.
Jan
Heres some rules I learned as an apprentice.
Mustly from Martin-Marietta`s "HANDBOOK OF WORKMANSHIP" (rocket science !)
All signal or DC carrying wires should be twisted hard/tight.(use a drill and a vice to twist)
+V,-V,0 V should be braided in hand,again tight.
All to minimize noise coming out from or into the wires.
And yes,it looks nice to.
Connect all 0V to the same point.(star)
If you are using screened cable for input and having hum,try disconecting the screen at one end.
Jan
Thanks Variac and 6L6!!!!!
This was getting a bit worrisome because I really love the sound of the preamp and it is very hard to find in the States. I could not seem to find a compatible amp that I could afford and you guys pointing me to the F4 was the answer I was looking for.
I can't wait to start but this will be my first amp build so I will take it slow and work from 6L6's great build thread. I am getting together the parts and cost list.
Is there a BOM list that I can upload to Digikey or Mouser? Also, is there a place to find enclosure parts and a toroidal transformer of appropriate value?
I work at a design school so I have access to a machine and wood shop.
Lastly, what is the appropriate size of heatsink that I should get for each channel?
Sorry about all the questions
A big thanks for suggesting this amp it seems to be exactly what I was looking for.
Cheers,
Enochrome
Guess I spoke too soon. The store has them in stock.
Does anyone know if a Little Dot III tube preamp/headphone amp will work with the ACA?
I tried it with a Sure tk2050 Class-d amp and got a loud hum and bad speaker bump. Thought it was going to blow up the speakers.
I'd like to try it when I get the ACA's done but, I don't want to damage them or my speakers.
Does anyone know if a Little Dot III tube preamp/headphone amp will work with the ACA?
I tried it with a Sure tk2050 Class-d amp and got a loud hum and bad speaker bump. Thought it was going to blow up the speakers.
I'd like to try it when I get the ACA's done but, I don't want to damage them or my speakers.
Don't know about the hum... Did you follow the recommended power on and off sequence? Little Dot's manual recommends letting the Little Dot warm up for about a minute before turning on the power amp and turning the power amp off first when powering down the system. That should avoid the bump.
Being mostly a tubophile I had to take the plunge into the Pass ACA amp. With its weeny 5 watt output I still manage to get a full-bodied sound on my sensitive speakers. The only snag is that it needs some preamp boost before going through my LS-DCB1 (another Pass – Thank you so much Mr Pass). But I like it a lot, it’s so musical, compared to my favourite JC Morrison 6L6-EF86 SE tube amp.
I built it as a test from scraps I hoarded a long time before. Surely, it’s not the last word in construction, far from it, but I like to recycle parts. It has a computer PS fan to cool things up in this summer heat. I’m playing it right now and there is a background hum. The case is a metal one (from the same PS unit) and the circuit GND is not earthed to the case. Before making this connection I would like to ask you a question:
There are 3 gnd points on the pcb which I suppose are all connected. Is this so? The 3 gnd points are: 1) the 19V PS gnd; 2) LS output gnd and 3) the Signal In gnd. Now, from which Gnd point should I wire the ‘star’ earth to the metal enclosure/case?
I built it as a test from scraps I hoarded a long time before. Surely, it’s not the last word in construction, far from it, but I like to recycle parts. It has a computer PS fan to cool things up in this summer heat. I’m playing it right now and there is a background hum. The case is a metal one (from the same PS unit) and the circuit GND is not earthed to the case. Before making this connection I would like to ask you a question:
There are 3 gnd points on the pcb which I suppose are all connected. Is this so? The 3 gnd points are: 1) the 19V PS gnd; 2) LS output gnd and 3) the Signal In gnd. Now, from which Gnd point should I wire the ‘star’ earth to the metal enclosure/case?
I'm sure to be corrected if I'm wrong... I don't believe that you need to run a star to the case. If you look at the pictorial build, there is no ground to the case:
http://www.diyaudio.com/forums/diyaudio-store/221212-amp-camp-amp-1-pictorial-build-guide.html
The board grounds the heatsink though the standoffs. Most cases won't be earth grounded because of the brick type supply.
EDIT: I reread what sonata wrote, realized the question was not answered.
The IN-, OUT+, power, and case ground are all connected (see schematic)
A star won't hurt.
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