Amp Camp Amp Kit 1.6/1.8

Crap on a stick; My OHM measurements on an old HP 974A voltmeter differed from my OHM measurements on a newer Agilent U1252B voltmeter. I guess that I have a new "favorite" DVM. With the Agilent DMV, the supplied components agreed with their markings and the schematic. The lesson is, when in doubt, measure twice on recently calibrated equipment. Duh.
 
New Question; I purchased two 1.6 kits with the Meanwell 24 VDC power supply. The 3 Watt resistors for R1, R2 are listed a 0.47 ohm and the resistors for R3, R4 are listed a 0.68 in the build guide, yet the resistors that I received were 0.68 and 0.82 ohm. Is this correct and should I use the 0.68 are R1, R2 and the 0.82 for R3, R4??

Suggest to measure the resistance of your DMM. Just measure without any resistor. Mine is not zero, but .8 Ohms, so I get 1.27 Ohms when I measure the 0.47 Ohm resistors..
 
Hi all, I have a few questions about the V1.6 that I've bought from DiyAudio and can't seem to find the appropriate answers or place to ask them so I'm piggybacking this thread, if anyone thinks that I should be someplace else, please feel free to bump me.
1. In the kit it mentions testing resistances of components (resistors) but doesn't give any tolerances, what should I accept for off-tolerance on components?
2. I couldn't find anywhere on HIFi2000 website where to buy the heatsinks, as I live in the UK, it's already cost me an arm and a leg just to get the bare kit (import duty, taxes, shipping etc) so I was looking to source those other bits from Europe if possible, can anyone help?
3. I would like to make the cabinet from rosewood, having only the heatsinks as metal, and making sure grounds are all connected. can anyone perceive any problems here?
4. I've been looking for a kit for a decent pre amp, but there appears to little mention if any, most just point in the direction of an existing one being suitable.
If I find none, I'll resort to what I did when I built a T class amp (tripath chip) and my first, a Gainclone, in which I added a selector switch with a second set of RCA's to accept a tuner as well as CD player, and an Alps potentiometer making them integrated.
They both sound great by the way, but have problems: The T class is so high frequency that it obscures any radio signal rendering a DAB tuner useless, and the Gainclone has no speaker protection, but naturally, its simplicity makes it sound good.
Perhaps someone could help here?
TIA
 
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New Question; I purchased two 1.6 kits with the Meanwell 24 VDC power supply. The 3 Watt resistors for R1, R2 are listed a 0.47 ohm and the resistors for R3, R4 are listed a 0.68 in the build guide, yet the resistors that I received were 0.68 and 0.82 ohm. Is this correct and should I use the 0.68 are R1, R2 and the 0.82 for R3, R4??

I'm guessing your test leads are 0.2 ohms and this resistance value is being added to your resistance measurements. Fancy multimeters have a "delta relative mode" to work around this, or follow Alan's advice in the next post.

I couldn't find anywhere on HIFi2000 website where to buy the heatsinks, as I live in the UK, it's already cost me an arm and a leg just to get the bare kit (import duty, taxes, shipping etc) so I was looking to source those other bits from Europe if possible, can anyone help?

Due to VAT regulations, anyone in the EU needs to buy the chassis directly from Hifi2000. They are currently sold out, but you can pre-order the heatsink from them directly when we next do a pre-order. We don't have the heatsinks available separately pre-tapped (they will be eventually sold as 2U Deluxe heatsinks), however you could buy this heatsink, and then tap yourself or have them do it (EUR35 per heatsink additional).
 
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Thanks for the reply; both DVMs report "0.L" when circuit is open.

There is a little confusion here.
What resistance do you measure with your probes shorted together? (''without any resistance'').
Most meters are poor at reading below 1 ohm because of the resistance of the leads and their connections, battery condition and design, so when you short the probes together you are measuring 'that' resistance. Subtract that from the resistor you checking for a better figure. See Jason's link but not many cheaper meters have a delta function...
 
Hi all, I have a few questions...

1. In the kit it mentions testing resistances of components (resistors) but doesn't give any tolerances, what should I accept for off-tolerance on components?
2. I couldn't find anywhere on HIFi2000 website where to buy the heatsinks, as I live in the UK, it's already cost me an arm and a leg just to get the bare kit (import duty, taxes, shipping etc) so I was looking to source those other bits from Europe if possible, can anyone help?
3. I would like to make the cabinet from rosewood, having only the heatsinks as metal, and making sure grounds are all connected. can anyone perceive any problems here?
4. I've been looking for a kit for a decent pre amp, but there appears to little mention if any, most just point in the direction of an existing one being suitable.
If I find none, I'll resort to what I did when I built a T class amp (tripath chip) and my first, a Gainclone, in which I added a selector switch with a second set of RCA's to accept a tuner as well as CD player, and an Alps potentiometer making them integrated.

Perhaps someone could help here?
TIA
1, Tolerance is specified on the resistor itself. Look up 'resistor 5 band colour code'. So most finish with a brown band which is + or - 1%. (No need to worry as long as they are within 5% either way really.)
The larger 3 watt jobbies are 5% - it is written on them. Note previous questions and answers from dwpeterson about measuring them first.
2, See Jason's answer. Also trade under 'Modushop.biz'
3, No, not recommended. Make as much from metal (aluminium) as possible with plenty of ventilation. They do run very warm even then.
4, There are suggestions on the main ACA thread (Amp Camp Amp - ACA) but build it and try it first...
Alan
 

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Long story made short - inexpensive DMM have a hard time reading ohms below 10.

If the resistor is marked clearly (particularly the 3W) and it's less than 10ohm, believe the making.

My big push for measuring everything before stuffing is to minimize placement errors. The big resistors are clear enough it can be skipped.
 
Long story made short - inexpensive DMM have a hard time reading ohms below 10.

If the resistor is marked clearly (particularly the 3W) and it's less than 10ohm, believe the making.

My big push for measuring everything before stuffing is to minimize placement errors. The big resistors are clear enough it can be skipped.


I value your "measure before stuff" philosophy. I'm sure it's a one part that contributed to the minimal hassles I had completing the build.



As a noob, I did it for the power resistors anyway and made allowance for tolerance. I even set up a little spreadsheet to list out the component values (see attached).


Trust me, I had the schematic on hand as well but I found it easier to read off a list rather than go cross eyed trying to find the values off the schematic when I was doing resistance checks. That approach may not be recommended for some reason but it helped me.


I would have been more at ease if I'd had the BoM in spreadsheet format to do a complete inventory of the kit contents - granted, the photos in the build guide work but being an engineer (not electrical / electronics), lists work for me ... just the way I'm wired ... (yes pun intended, let me emoji this for everyone) ... :rolleyes:



Maybe you, and your store / mod compadres, could give posting the BoM idea some thought for the future.


I've said it before but will say it again - great build guide and thanks for all your help both here and in the guide... :up:
 

Attachments

  • ACA v1.6 Component Values.xlsx.zip
    7.3 KB · Views: 87
I want to use Rosewood as a cabinet (semmyroundel)

Semmyroundel
3. I would like to make the cabinet from rosewood, having only the heatsinks as metal, and making sure grounds are all connected. can anyone perceive any problems here?
—————————————————————————————————————————

In most cases there’s no problem using wood as a cabinet but having a metal cage around your electronics does reduce the possibility of picking up straight interference example fluorescent lights LED lights and other electronics devices.
This is easily taken care of they sell thin or thick gauge copper tape in different widths you can completely line the inside of your wooden cabinet with copper. Slightly overlap the lengths of copper it has adhesive on one side. And if you really want to get carried away a little bit you could use your soldering iron to solrer the overlapped tape seems together. When scanning and looking for old antique radios in some electronics that were made out of wood you would see this in some old radio gear and electronics test gear. Make sure you allow for ventilation heat always travels up naturally. So directly under hot components if you place some vent holes below and directly above a natural convention from heat to air would naturally flow Straight pulling from the bottom cool air of the chassis flowing over the component and then out of the vent holes directly above.
 
I'm building two ACA V 1.6's as RCA input monoblocks.

Thinking of using the back switch as a mono/stereo selector, switching the 39K resistor in/out between the appropriate points on the backplate.

Is there any possibility of damage should the switch be toggled by accident with the amp powered up and connected?
 
1, Tolerance is specified on the resistor itself. Look up 'resistor 5 band colour code'. So most finish with a brown band which is + or - 1%. (No need to worry as long as they are within 5% either way really.)
The larger 3 watt jobbies are 5% - it is written on them. Note previous questions and answers from dwpeterson about measuring them first.
2, See Jason's answer. Also trade under 'Modushop.biz'
3, No, not recommended. Make as much from metal (aluminium) as possible with plenty of ventilation. They do run very warm even then.
4, There are suggestions on the main ACA thread (Amp Camp Amp - ACA) but build it and try it first...
Alan
Many thanks Alan, I suppose Ill just get a front of rosewood to skin the metal box as I'm fed up with standard looking amps.
 
If you built the 1.6 with front on / off switch and the back panel with RCA mono / stereo switch as per the build guide, you should be fine!!

Hope this helps,
Rafa.

I will be using the front switch for power on/off.

I've looked again and again at the back switch wiring in the v1.6 build guide, all I can find is wiring for the back switch as power on/off.

Can not find any reference to wiring back switch for mono/stereo mode switching. All I can find are instructions for an external jumper that places 39K resistor in series between RCA IN and speaker Black.

1. Please help me find instructions for back switch as mono/stereo selector, or is back switch used to put an internal resistor/jumper in place when switched to mono, and internal resistor/jumper removed when switched to stereo?

Also, my DC supply jack has only two tabs. I'm using center tab for DC+ to the front power switch, and connected the outer tab to the jumper between speaker red terminals.

2. Anything else need to be done here?
 
Here is all the info you are looking for:
Amp Camp Amp V1.6 Build Guide - diyAudio Guides

Edit: corrected link

I completely overlooked the schematic, and was relying on the back panel wiring photographs.

You are correct, all the information I need is in the build guide, but I was blind to it. Embarassing

To all, please forgive me for cluttering the thread with questions that had already been answered.
 
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Jason / 6L6,
Perhaps people are missing this incredible new guide, because the Kit item in the store links to the older 1.5 version of the guides. I think that clicking on the "all new detailed guide..." link should go to the new 1.6 guide now, instead of the 1.5

Rafa.

Good catch :) All links have now been updated.
 
I completely overlooked the schematic, and was relying on the back panel wiring photographs.

You are correct, all the information I need is in the build guide, but I was blind to it. Embarassing

To all, please forgive me for cluttering the thread with questions that had already been answered.
In the bottom part of the guide, you will find pictures that closer resemble (or are identical!) to your current set, including the back switch with less pins, and connecting the mono resistor inside.

Ask as much as you need... 6L6 likes to say: the only stupid question is the one you don't ask!

So fire ahead until you are comfortable with the answers, everyone here will help with very good spirits!

Best regards,
Rafa.