I actually have 2 kits (Amp Camp Amp Parts Kit Only – diyAudio Store) which I won‘t build. Would give it for what I paid for...
Pm if interested.
David
Pm if interested.
David
Hello All - made a total dumb move tonight while wrapping up my Amp Camp - while trying to desolder a little too much solder that got onto the the tip of the DC input jack's pin, I melted the insulation and ruined the jack (dummy).
Anyhow - anyone have the part number for the DC input jack?
Anyhow - anyone have the part number for the DC input jack?
839-1292-ND is the part# at Digi-Key
2.54 ea. but very nice quality so we feel worth it.
try this:
https://www.digikey.com/products/en?keywords=839-1292-ND
2.54 ea. but very nice quality so we feel worth it.
try this:
https://www.digikey.com/products/en?keywords=839-1292-ND
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HiI am hoping to end up with a basic stereo ACA with a volume pot, an internal 24v smps https://www.mouser.co.uk/ProductDet...=sGAEpiMZZMti11uKQaALGXid3mijwLpwvVq38qXuprI=
built into my own enclosure.
I have a 2v output CD player and a pair of Wayne Parhams excellent 2Pi speakers (95 db sensitivity)
Pi Speakers - two Pi loudspeaker performance data
My listening room is quite small and I am using is a single ended EL84 valve amp with an output of about 3w. More than adequate.
Reading this thread and having just passed 400 pages I have made many notes so I am hoping that what I am proposing should not be too radical.
Some questions to get me started.
1. A 10k pot is planned as a low resistance has been generally recommended. Should the wiring for the pot to be as I would with my valve amp, RCA-POT-PCB etc?
2. I would like to follow the recommended modifications, R15-add the bias resistor, change R12 from 68K to 39.2K and adjust the DC output to 12v.
3. I’m planning to use a couple of finned heatsinks that are about 8’’ long x 3’’ high x1.5’’ deep, if OK?
I will have plenty of ventilation holes in the top and bottom covers and the amp will sit on an open shelf.
Advice and comments welcome, please be gentle as this is a totally new direction for me. I am learning and still have so much to learn.
Graham
Pass DIY Addict
Joined 2000
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Saracenblue: your sinks sound perfect. I'm running at 19v and bias level without the additional resistor on sinks that measure 8" x 3" x 1.5" for each channel and temps are fine.
I built one of my ACAs as you describe: RCA-> stepped 20k pot -> PCB. The volume pot works OK, but even with a log taper, it doesn't quite function as you'd expect a volume knob to work. Some steps sound larger than others. Somewhere, someone mentioned that using a pot in the manner really needs to be accompanied by an additional buffer to work "properly." Perhaps others will have commentary here...
I built one of my ACAs as you describe: RCA-> stepped 20k pot -> PCB. The volume pot works OK, but even with a log taper, it doesn't quite function as you'd expect a volume knob to work. Some steps sound larger than others. Somewhere, someone mentioned that using a pot in the manner really needs to be accompanied by an additional buffer to work "properly." Perhaps others will have commentary here...
@Saracenblue & Eric
I have also built the ACA with R15 mod. That translates to around 6W pc. With a B1 buffer fed by FLAC files thru a Sabre DAC, the volume was so-so on 94dB speakers (Dual 3FE25-16 Karlsonator).
Then someone on diyAudio mentioned that total gain of a system should be about 30dB for adequate music levels. I think the gain of the ACA is 15dB or thereabouts and the B1 buffer has no gain. I then built an AKSA Lender preamp and set the gain to 15dB to get to the recommended 30dB total gain. Now it's a different system with volume to spare on even the quietest of tracks.
I'm not saying that the AKSA Lender preamp is a must, because it's a more complicated build than the ACA. Just be aware that unity gain (buffers or no preamp) can probably not drive the ACA to its full potential.
I have also built the ACA with R15 mod. That translates to around 6W pc. With a B1 buffer fed by FLAC files thru a Sabre DAC, the volume was so-so on 94dB speakers (Dual 3FE25-16 Karlsonator).
Then someone on diyAudio mentioned that total gain of a system should be about 30dB for adequate music levels. I think the gain of the ACA is 15dB or thereabouts and the B1 buffer has no gain. I then built an AKSA Lender preamp and set the gain to 15dB to get to the recommended 30dB total gain. Now it's a different system with volume to spare on even the quietest of tracks.
I'm not saying that the AKSA Lender preamp is a must, because it's a more complicated build than the ACA. Just be aware that unity gain (buffers or no preamp) can probably not drive the ACA to its full potential.
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+1
Steve Luck is absolutely correct about that. I'm also using the Meanwell LRS-100-24, but it is external and no hum gets into the audio chain.
I know an integrated amp sounds attractive, but it is not very practical for DIY. Manufacturers do a lot of R&D and experimenting before releasing an integrated amp in the market.
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Pass DIY Addict
Joined 2000
Paid Member
This is why all of my ACAs are powered by Dell laptop bricks. It provides build simplicity and keeps the PSU away from the audio circuit. Some of the cheaper no-name laptop bricks spew all sorts of RFI into the air and into the line. It also provides a nice and small enclosure - check the link in my signature for images.
Graham - my 2 cents worth:
The ACA is a great first project - I was delighted with mine and have run a bridged pair for some time. However, once hooked I couldn't resist the next step up and I now have a working M2x 'running-in'. The improvement over basic ACAs is not subtle even to these old ears, making the 'Tungsten treatment' absolutely imperative. So if I were in your shoes I would be making the capacitor substitutions as well.
If by a 'totally new direction' you mean wielding a soldering iron, careful scrutiny of pictures on ebay (as opposed to often misleading headings) reveals a thru-hole practice kit for less than £3 which could be a useful starting point. Plus umpteen videos on Youtube, of course.
The ACA is a great first project - I was delighted with mine and have run a bridged pair for some time. However, once hooked I couldn't resist the next step up and I now have a working M2x 'running-in'. The improvement over basic ACAs is not subtle even to these old ears, making the 'Tungsten treatment' absolutely imperative. So if I were in your shoes I would be making the capacitor substitutions as well.
If by a 'totally new direction' you mean wielding a soldering iron, careful scrutiny of pictures on ebay (as opposed to often misleading headings) reveals a thru-hole practice kit for less than £3 which could be a useful starting point. Plus umpteen videos on Youtube, of course.
Thanks so much for replying. All good stuff, can't beat input from experienced ACA builders.
Eric
I admit that I was heading in the direction of one of those stepped attenuators but after your comment I will opt for the trusty Alps blue velvet and I'll get those heatsinks ordered.
Skylar88 and Steve
I can do cases/boxes, there will be room on my shelf for the separate power supply. Also more space in the ACA box is no bad thing.
Regarding that Mean Well LRS-100-24, have you encountered noises when powering up and thumps when powering down? I treasure my speakers. Connectors from the power supply to the back of the ACA, guess we only need two pins, +and -. What have you used?
I'll check out the Aksa Lender, consider it added to the list.
Davidjt
I get by with my soldering iron. The Pace, basic soldering guide on Youtube is my favourite source especially when I come up against unusual connectors.
Thanks guys for your support.
Eric
I admit that I was heading in the direction of one of those stepped attenuators but after your comment I will opt for the trusty Alps blue velvet and I'll get those heatsinks ordered.
Skylar88 and Steve
I can do cases/boxes, there will be room on my shelf for the separate power supply. Also more space in the ACA box is no bad thing.
Regarding that Mean Well LRS-100-24, have you encountered noises when powering up and thumps when powering down? I treasure my speakers. Connectors from the power supply to the back of the ACA, guess we only need two pins, +and -. What have you used?
I'll check out the Aksa Lender, consider it added to the list.
Davidjt
I get by with my soldering iron. The Pace, basic soldering guide on Youtube is my favourite source especially when I come up against unusual connectors.
Thanks guys for your support.
I'm using Easy Peasy cap multipliers in my ACA and don't get any thumps or noises at all. If you're interested, I'll post more info. It's really easy to build dead-bug style and cheap, but drops 4V. Fortunately, the LRS PSU is adjustable voltage-wise, so I could get back up most of the 4 volts. An added bonus of the cap Mx is that it effectively cancels all crosstalk, so I have basically two monoblocks in one case. The soundstage is exceptional.
I used a beefier than usual power connector: Lumberg 1614 Series, 1mm Snap-In DC Power Socket and Connector.
Very wise decision. It's absolutely superb and even sound-wise, there is no comparison between it and the B1 buffer. And this coming from a Pass fan.
Pass DIY Addict
Joined 2000
Paid Member
I think you've misinterpreted my intentions. I don't believe my observations are specific to stepped vs non-stepped pot. My comment was focused on inserting any pot at all into this location of the circuit without some additional accompanying changes...
I am wondering if others have had any similar experiences?
Mark says the ACA kits won’t be available for 3 months. That’s a loooong time. What other kit options are there? Eric mentioned the MOFO, but I’d rather not deal with the voltage front end, which I don’t understand, and I’d rather have a complete kit with all the parts, instructions, etc. Any ideas?
Pass DIY Addict
Joined 2000
Paid Member
If the PCBs are in stock (I haven't looked) you might want to consider building one on your own. It may seem a little overwhelming right now, but there is no greater confidence builder than ordering all of the parts for an amp and building it yourself. I've built 5 or 6 of them, not one was from the kit. Plus, you've got an entire community here to support you and answer your questions!