Surprised that no-one has answered your question yet.
Easy.
You wire the new ones in parallel with the original RCA Out.
Solder some thin, flexible wires to the pins of the RCA's or to the underside of the PCB. You should be able to find a suitable spot to take off the added Output.
Go slowly and carefully, trying not to make a mess and more trouble.
Enjoy.
Easy.
You wire the new ones in parallel with the original RCA Out.
Solder some thin, flexible wires to the pins of the RCA's or to the underside of the PCB. You should be able to find a suitable spot to take off the added Output.
Go slowly and carefully, trying not to make a mess and more trouble.
Enjoy.
One thing to keep in mind when simply adding another set out outputs in parallel: the output impedance increases. Depending upon your cablesʻ capacitance and the input impedance's of the driven amplifiers, you may end up with a roll-off in high frequency response (as I understand it). The higher the capacitance, the greater the load on the preamp output and therefore the greater the possibility that there will be high frequency roll-off. There is a way for calculating both the increase in impedance from paralleled outputs and the the decrease in roll-off frequency due to capacitance, but I am not knowledgable in that regard (sorry).
One way to avoid the issue is to drive the second pair of outputs with a buffer, such as the Pass original B1 buffer. PCBs and JFETS for the B1 buffer are available at PASSDIY.com. The Pass B1 requires up to 24 volts of power, and therefore is compatible with the PS for the ACP+.
One way to avoid the issue is to drive the second pair of outputs with a buffer, such as the Pass original B1 buffer. PCBs and JFETS for the B1 buffer are available at PASSDIY.com. The Pass B1 requires up to 24 volts of power, and therefore is compatible with the PS for the ACP+.
No, it doesn’t. The downstream input impedance appears lower.
Mostly the right idea, however in the case of ACP+, which has an output that will handily drive 20ohm headphones, it absolutely will not matter nor change at line level. It’s a rocket-powered flamethrower where line level needs little more than a candle flame.
This is a reasonable statement for some other preamps, yes. But not this one.
Parallel the line outputs with no concern.
That would increase the capacitance, and there’s not much reason to do so. It’s probably on that preamp to help with switching selection noise.
Nice to know that the ACP plus has sufficient power to drive two separate devices! I had been thinking of adding a second set of outputs and was planning to use my B1 buffer which I had been saving for such an application. Thank you, 6L6 for your advice, as it will save me from an an- needed use of the B1.
If they are from the last run of the kits the 1000 uF caps are either Nichicon or Panasonics. If from a different vintage, let me know and I can look up what shipped when your kit was created. In any event, feel free to use either in the "gold" spot as they are both very high quality electrolytic caps - as have all of the 1000uFs that have been included in the kits. I have used every one of the 1000uFs that have shipped in the kit since I started building them, in the "gold" location and have found zero difference to my ears and a few others that have compared them. BUT don't take my word for it. Thats why we're here doing the DIY thing! Feel free to prove this to your own ears by swapping them around and giving it a critical listen.
These are the specs for the 1000uf caps in the latest run of the store kits:
https://www.mouser.com/ProductDetail/667-EEU-FS1V102LB
https://www.mouser.com/ProductDetail/647-UHV1V102MHD
--Tom
To run in parallel with the default one, or switched between the two? The latter is easy; just use a high quality 2 pole switch like the ones used for other inputs that you've seen like this nice setup Brosky offers with a nice break-out board for ease of installation:
https://glass-ware.stores.turbify.net/inseswandpcb.html
If you want to run them in parallel to drive two output loads, thats another thing altogether.
--Tom
https://glass-ware.stores.turbify.net/inseswandpcb.html
If you want to run them in parallel to drive two output loads, thats another thing altogether.
--Tom
Hello all
I am looking for ACP+ project. I have read the document, it states that all resistors are 1/2 watt except some higher wattage one.
I observe the schematic and I did not find the reason that it need 1/2W resistors. In my opinion , most of them can go with 1/4W resistors.
What is a reason behind 1/2W of resistors, am I missing something?
Actually, I am planing use dale rn55 resistors for this project. Is it ok to use for this project?
Thank you for every answer.
Tanwa
I am looking for ACP+ project. I have read the document, it states that all resistors are 1/2 watt except some higher wattage one.
I observe the schematic and I did not find the reason that it need 1/2W resistors. In my opinion , most of them can go with 1/4W resistors.
What is a reason behind 1/2W of resistors, am I missing something?
Actually, I am planing use dale rn55 resistors for this project. Is it ok to use for this project?
Thank you for every answer.
Tanwa
I was playing with QA403 (an audio analyzer) and tried a few things with my ACP+. I noticed there is something happening ~18kHz. It does not seem to be related to the power supply and the input. I tried both a battery and wall mount switching power supply, and I do not see this when the analyzer is in loop back so it is not related I guess to the source. Is this normal, why would be the reason for this ?
ACP+ powered with battery, no input signal:
ACP+ powered with battery, and with input signal from the analyzer:
ACP+ powered with wall mount switching power supply (Triad Magnetics WSX240-1000), and with input signal from the analyzer:
ACP+ powered with battery, no input signal:
ACP+ powered with battery, and with input signal from the analyzer:
ACP+ powered with wall mount switching power supply (Triad Magnetics WSX240-1000), and with input signal from the analyzer:
But it exists also when ACP+ is battery powered. QA403 audio section is also isolated from USB and I dont see this in other tests. I dont know if it can be due to environment, I did this test in a different place then I usually do.
I think at this price point QA403 is pretty nice.
I think at this price point QA403 is pretty nice.
Mark's SMPS filter is effective right in that range. Try using that after the PSU and before the ACP+ and I bet you will see that artifact disappear.
--Tom
Does your analyzer have a float and ground switch?
Try it both ways?
I had an issue like this many years ago with the ACA. It ended up being the switch mode power supply. When tested with a switch mode power supply that had a ground pin there was no noise. When testing with a switch mode power supply without a ground pin it was noisy.
The 18kHz could be conducted and radiated interference. The 18kHz noise while using the battery is so insignificant (-120dB), it’s not worth worrying about.
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No the analyzer does not have such a switch, so the audio section is always floating. A few things are mentioned in some places and I tried some things but it did not change anything. On the other hand, I tried another (commercial) device and it is pretty silent.
My switch mode power supply has 2 pins, I should try one with grounding, good idea.
My switch mode power supply has 2 pins, I should try one with grounding, good idea.
Hey all,
I'm just in the early planning stages of my 'ACP+ in a chassis with PSU' build, and thought I'd get some suggestions now before I do anything irreversible/regrettable.
(I know some of you may feel putting the power supply in the chassis is regrettable, but I'm doing it anyway)
Here's the basic idea - the board in a Galaxy chassis with a FlexReg single rail supply. Here are my random thoughts so far;
Any suggestions or cautions welcome. Especially on how to cut an IEC inlet hole into the backplate. I'm thinking to trace the outline, drill holes into the four corners of the outline, dremel cut between the holes, and then file clean. Getting a good angle with the dremel seems tricky though - might need one of those umbilical thingos.
I'm just in the early planning stages of my 'ACP+ in a chassis with PSU' build, and thought I'd get some suggestions now before I do anything irreversible/regrettable.
(I know some of you may feel putting the power supply in the chassis is regrettable, but I'm doing it anyway)
Here's the basic idea - the board in a Galaxy chassis with a FlexReg single rail supply. Here are my random thoughts so far;
- I plan to have the pot and RCAs off the board, as getting the holes to line up with the board positions seems like an absolute bear
- I want to run a switch on the front of the chassis (hence the AC input side of the FlexReg facing the front)
- I was considering having a gal steel sheet fence between the FlexReg board and the main board, drilling a hole with a grommet to feed the power through to the main board, but I'm not sure it's necessary or just paranoia (my Whammy doesn't seem to have any issues with having the transformer right there on the board, not sure if ACP+ would be any more susceptible to issues)
- I might bridge the on board power switch pads, although I guess having an unused internal switch doesn't harm anything
- there are three different locations from which I could run an LED (FlexReg power on, FlexReg positive rail, ACP+ LED), but I figure the ACP+ location makes most sense (I suppose there'll be a tiny delay, but hardly noticeable)
- I assume I can just populate the ACP+ power section caps without issue, even if they are redundant?
- I figure I need to isolate the ACP+ board from chassis ground and, ideally, star ground to the chassis at the chassis ground mounting hole on the FlexReg board - so nylon supports for all but that position? Do I need to isolate the pot also?
- I was thinking I could slide some m3 nylon nuts into the channels on the side panel closest to the FlexReg, and then use a chain of two zip ties to hold the AC power input wires (twisted) up and to the side.
Any suggestions or cautions welcome. Especially on how to cut an IEC inlet hole into the backplate. I'm thinking to trace the outline, drill holes into the four corners of the outline, dremel cut between the holes, and then file clean. Getting a good angle with the dremel seems tricky though - might need one of those umbilical thingos.
I just took a look. Very cool. I considered having things milled/engraved, but I don't know much about the relevant software. I might try it by hand first, if for no other reason than to make sure the layout works. My plan is sort of the mirror image of yours. I appreciate the offer though.