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Amp Camp Amp Kit V1.6
Amp Camp Amp Kit V1.6
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Old 12th September 2019, 02:01 PM   #541
6L6 is offline 6L6  United States
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Amp Camp Amp Kit V1.6
Panaman west - the ACA is powered by a 24v 5A laptop computer power supply. The latest generation of these PSU are remarkably quiet, tightly regulated, and sound very, very good. There is no filtering on the PSU in the amplifier itself, none was found to be necessary, although you could certainly experiment and see if you find some benefit to added capacitance.
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Old 12th September 2019, 06:52 PM   #542
panama west is offline panama west  Panama
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Thank you for the information, trying to decide whether to buy a used amp or build one to drive my 94db towers. Would love a first watt but don’t have the budget thus wondering how far from the mark a 1.6 would fall. Nelson’s amps seem to all have no shortage of capacitance which scares me about the 1.6. I don’t want an anemic low end.
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Old 12th September 2019, 07:18 PM   #543
Mooly is offline Mooly  United Kingdom
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Amp Camp Amp Kit V1.6
When thinking of capacitance (across the rails) you absolutely must understand how the switching supply differs from a conventional transformer/bridge and reservoir cap.

The SMPS runs at very high frequency and so needs a correspondingly smaller cap to achieve the same 'recharge' of the cap. The time between each cycle is just so much shorter.

Have a look at this. Two power supplies, one is running at 50Hz, the other at 50 kHz. The loads are identical and draw just over 2 amps.

Which rail has the most ripple? One has 5000uF and the other just 100uF.

In the SMPS the high frequency ripple will be further reduced by careful filtering, probably using a tiny inductor and another small cap.

Throwing a much larger electrolytic across the SMPS won't kill that ripple, one reason being the relatively poor performance of an electrolytic at HF. Also, and this is very important, adding to much capacitance can upset the operation of the SMPS by causing problems such as poor transient response (voltage output in response to sudden load variations) or in extreme cases cause the supply to either trip or think there is a rail short somewhere.
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Old 12th September 2019, 07:28 PM   #544
Mooly is offline Mooly  United Kingdom
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And to show how a simple inductor and a small cap reduce that HF ripple to practically nothing, here is a close up of the rail voltages now. Look how small the cap is:
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Old 12th September 2019, 07:50 PM   #545
panama west is offline panama west  Panama
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Thank you for illustrating, that being said in regards to device balance if that is putting it properly , how is the low end in this amp compared to other low watt Pass amps. Looking for great mods and highs but also want good low end as well. Running Tekton Lores. Thanks again. I’m just getting started in the build knowledge part and have much to learn.
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Old 12th September 2019, 09:31 PM   #546
Mazeppa is offline Mazeppa  United States
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Amp Camp Amp Kit V1.6
My Tekton Lore Reference speakers on mono ACA v1.6's were quite good on the low end, mid-bass especially.
Tried with and without my sub, and it seemed to depend on the recording whether it was really needed or not.


Remember YMMV always applies, but the ACA (better yet, pair of them) is a good bet.
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Old 13th September 2019, 06:42 AM   #547
Mooly is offline Mooly  United Kingdom
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Quote:
Originally Posted by panama west View Post
Thank you for illustrating, that being said in regards to device balance if that is putting it properly , how is the low end in this amp compared to other low watt Pass amps. Looking for great mods and highs but also want good low end as well. Running Tekton Lores. Thanks again. Iím just getting started in the build knowledge part and have much to learn.
The ACA interacts with its load more than most amps due mainly to its relatively high output impedance. Another quick simulation example will highlight that. Here we see the ACA into an 8 ohm resistive load and then a reactive load like a speaker. In this case the speaker model is for B&W703 floorstanders. The rise in output at LF for the resistive load is down primarily to the way the feedback is wrapped around the circuit and applied before the input coupling cap.

You can see how the ACA output is altered by the impedance curve of the speaker and it is in many ways it is precisely that interaction that gives the ACA it's colour and musicality.
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Old 25th September 2019, 10:50 AM   #548
Steve Luck is online now Steve Luck  New Zealand
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Oh Wow. felt crap this morning fighting a bug that others in the office have been passing round so took a day off work and with very slow, careful determination finshed building my second ACA for bridged monoblock purposes.

Had music going all afternoon sounding very high end. Streaming Tidal service from a Nativ streamer to Cambridge DAC Magic plus and into the ACA and onto Carfrae little big horns (authorised kit version). So the ACA supplies Lowther DX4 in a back loaded horn config with a signal from the speaker cables being taken to drive plate amplifier and subwoofer setup. 106db per watt.

The mind f**K happened when I ran the movie Interstellar from Apple TV through the system. I swear I was looking to the ceiling for bits of rattling spaceship to fall down. The sound stage extends so far out and up from the speakers as to be totally bonkers.

The ACA aren't really driving the subs but the bass rumble coming through is a big improvement. It's got to be the single ended aspect. My normal Amp is a push pull class A Valve amp with seriously expensive output tubes. Maybe single ended valve amps are more like the ACA but I've never had the chance to hear one. Been looking at the Korg B1 options but I read it is boosting the signal which isn't something I need. Think I'd be better off with a passive attenuator set up. What an amazing little amp when hooked up to efficient speakers.
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Old 26th September 2019, 07:21 AM   #549
myleftear is offline myleftear  Switzerland
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Default Alternative Speaker-Connector (binding post)?

Hi all!

I am finally working on the kit, which is really great fun!
Just for aesthetical reasons, I think about using some other speaker-connector.
I am looking for some connectors that appear less "plastic", more humble, more "far-out" or more retro, like just a red and a black hole...
Haven't to be magical material, must not be absolute luxury.
more like these: http://www.solidcoreaudio.de/bilder/DSC_7377.jpg but for amps...

Any suggestions?

Thanks to all!

all the best
d.
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Old 26th September 2019, 08:22 AM   #550
Steve Luck is online now Steve Luck  New Zealand
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Like this:
Red 4mm PANEL MOUNT Socket | Jaycar Electronics New Zealand

Would work if you had banana plugs on your speaker cable.
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