Which solid state discrete stage amp is a good one to build? I might as well get started on one to do over this next year 😛 Maybe I can run across another chassis at flea market for $5 🙂
I wonder why the Gaincard sold for $3300 in 1999, if it wsan't as good as solid state.
I wonder how much of a noise improvement I'd have if I had can over the Corcom filtered IEC switched & fused AC inlet? Oh, I still need to redo the dc supply to amp board cabling as well.. twisting each pair individually like AndrewT suggests. Maybe that'll help with that noise.
All that twisting helps. Don't think IEC jack will do it. You need a power supply with multiple stages of CRC or CRCLC etc. they can be simulated to get the best component values for the lowest ripple given a specified load.
I have built a handful of the solid state discrete amps. Most are the ones designed by Apex in the giant thread. The FX8 Bimo mod is very good. So is the FH9.
I recently built the VHex 1.1 and this amp is really dynamic and quiet.
I am using it with a new PSU that has only 5mV of ripple.
Here is a small 50mm FX8 dual monoblocks.
The JFET input Circlophone is probably my best amp still. It's a sliding bias class A.
I have built a handful of the solid state discrete amps. Most are the ones designed by Apex in the giant thread. The FX8 Bimo mod is very good. So is the FH9.
I recently built the VHex 1.1 and this amp is really dynamic and quiet.
I am using it with a new PSU that has only 5mV of ripple.
Here is a small 50mm FX8 dual monoblocks.
The JFET input Circlophone is probably my best amp still. It's a sliding bias class A.
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How about Amp Camp Amp ? With an active crossover (1) the ACA will be driving the wideband speaker driver which would cover most of the frequency range and (2) the Chip Amp would drive the woofer to handle the lower frequency range. I am newbie so experts can give more precise advice.
Turns out my 300VA 25V transformer is needing 4A fuses because it keeps blowing the 3A ones on startup. (3A slow start from Radio Shack -- 5 x 20mm)
I'd like to implement a soft start perhaps, if it doesn't add any noise to the amp or affect sound quality. With a soft start could I get the fuse down to 1.5A or possibly even less?
I'll try and do some searches to figure out the soft start thing.. to be honest most of what I read here is way over my head -- I've got lots to learn.
xrk197a,
Thank you for sharing all those wonderful photos and information! Thanks Hiten as well. Maybe I'll build a solid state some day just so I can compare 🙂
Jennifer
Thank you for sharing all those wonderful photos and information! Thanks Hiten as well. Maybe I'll build a solid state some day just so I can compare 🙂
Jennifer
I CL60 thermistors on the transformer primaries will cure you starting issue.
As for other projects to try, the Class A Pass stuff is well supported on this site, PCBs are available on this site and sound great. No more $5 thrift store enclosures though, you are gonna need a lot more heatsink for Class A.
As for other projects to try, the Class A Pass stuff is well supported on this site, PCBs are available on this site and sound great. No more $5 thrift store enclosures though, you are gonna need a lot more heatsink for Class A.
So I guess a disspante 3u then? They aren't too terribly expensive.
I'll look into the "I CL60 thermistors" thanks.
I really want to get this B1 Buffer built next and then I want to build a DAC. Any ideas for a DAC? Using a 4 year old 24/96 Fiio now with 12v pyramid power supply along with a 7805.
EDIT: Listening to David Gilmour's "On an Island" CD right now on the LM3886 -- this album is recorded pretty well -- sounds great.
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No, you are going to need 4U or 5U. Mosfets sound better with more bias, so you want as much bias as possible...which means more heat. 4U is probably the minimum.
Here is Jwilhelm's box, it looks like a 3U?
My version of the same amp above (vHEX 1.1) runs fine with a 3in tall x 7.3in heatsink. 2U is 3.5in so would work for this amp but might be tight for the trafo so 3U may be better. It is 90w nominal at 8ohms and uses 80mA per MOSFET. I think 5U is roomy and nice but not needed from heatsink standpoint. Maybe if class A then need 5U.
My version of the same amp above (vHEX 1.1) runs fine with a 3in tall x 7.3in heatsink. 2U is 3.5in so would work for this amp but might be tight for the trafo so 3U may be better. It is 90w nominal at 8ohms and uses 80mA per MOSFET. I think 5U is roomy and nice but not needed from heatsink standpoint. Maybe if class A then need 5U.
That's class AB at 80mA and 90W, right?
The Class A Pass f5 ( a popular example) is 1.25A per channel (and only 25W). Guess where all the heat goes? That's why you need at least 4U. 5U can get you 2.5-3A per channel bias.
The Class A Pass f5 ( a popular example) is 1.25A per channel (and only 25W). Guess where all the heat goes? That's why you need at least 4U. 5U can get you 2.5-3A per channel bias.
I was at the electronics store and the owner looked up the CL60 and the example showed it on the secondary winding not primary.
So I really put it on the primaries?
I need two of the CL60, one for each primary right? How much will the current be limited? Could I get away with a 2A fuse after the mod? I am using 4A now.
Re-did the dc supply to amp board wiring along with speaker wires. Replaced with wire that has much thicker jacket and higher temp (105C vs 60C).
The dc supply to amp boards is stranded 18 AWG. The speaker wires are 18 AWG solid core -- to keep them self suspended well above the heatsink.
Also suspended the speaker wire over the heatsink further away from the LM3886 -- it was right over it before. Heatsink is cooler on the ends.
The dc supply to amp boards is stranded 18 AWG. The speaker wires are 18 AWG solid core -- to keep them self suspended well above the heatsink.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Also suspended the speaker wire over the heatsink further away from the LM3886 -- it was right over it before. Heatsink is cooler on the ends.
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Don't let people rain on your parade. Your amp is Just Fine, and they are talking about very subtle improvements IMHO.
I don't know if the CL60will be optimal for your amp as it's usually used for class A amps which have a relatively constant power draw, unlike a class AB Amp like your chip amp. I do like the idea of combining your chip amp for the bass and the ACA for the treble eventually.
Look up the Pass F-5 which you could build easily with what you now know.
No kit available here but only circuit boards. But as someone mentioned - heatsinks about 6x the size of the heatsinks you used for your chip amp
http://diyaudiostore.com/collections/power-amplifier/products/f-5
Here's the info on the ACA, which either comes with a full kit including 2 chassis (1ch per chassis) or just a circuit board. It's actually easier to build than your amp because it use Laptop Psu's to power it.
Amp Camp Amp Kit – diyAudio Store (BETA)
I don't know if the CL60will be optimal for your amp as it's usually used for class A amps which have a relatively constant power draw, unlike a class AB Amp like your chip amp. I do like the idea of combining your chip amp for the bass and the ACA for the treble eventually.
Look up the Pass F-5 which you could build easily with what you now know.
No kit available here but only circuit boards. But as someone mentioned - heatsinks about 6x the size of the heatsinks you used for your chip amp
http://diyaudiostore.com/collections/power-amplifier/products/f-5
Here's the info on the ACA, which either comes with a full kit including 2 chassis (1ch per chassis) or just a circuit board. It's actually easier to build than your amp because it use Laptop Psu's to power it.
Amp Camp Amp Kit – diyAudio Store (BETA)
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Iam not sure what transformer you are using but this:
http://www.diyaudio.com/forums/pass-labs/188691-illustrated-guide-building-f5-40.html
2nd post. You need 2 cl60s...they are inrush limiters. Once they heat up they will pass all the current. And they may reduce noise on the ac line as well.
As for the fuse, I don't know. 4 amps seems like a lot for a chip amp. But I don't know how much current they consume...Iam not an expert on chip amps by any means. Here is a discussion provoking hint: ceramic fuses sound better. Get some of those once it's not blowing fuses anymore.
The alternative to the cl60 would be a soft start board which are all over eBay and such. Most use a thermistor like a cl60 and a relay which closes after the thermistor is hot.
And wow. You have an electronics store with somebody there who knows how to look up parts? A human being at an electronics store with knowledge and information? Amazing. There isn't even a radio shack around me anymore. And all the staff there knows how to do is try to sell you a cell phone plan.
Yeah it's the owner of the store that helps me out. He's really knowledgeable in both analog and digital electronics. I love their service. I just bought some 18 awg wire from them today for the amp rewire. And they are only like 2 miles from me.
The ACA is a superb amplifier & REALLy good value. Better than any of my chipamps but not as powerful.
dave
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