similar budget line stage products?
Not really a "build" question - I had no issues with mine, other than some confusion over the sequence shown in detailed photos, and since I'm too lazy and inept to conduct a proper forum search, I thought I'd ask here.
I'm looking for recommendations on a similarly budgeted kit for line stage - as opposed to a simple buffer like B1, I'd probably need low gain as some of my DACs or even phono pre-amp have rather low output.
While I'm asking how about something like a DIY version of B4 - realizing of course that's a much more complicated function than a simple 6 Watt Class A amp, and would certainly cost more.
To echo the sentiment -big thanks again to Nelson for sharing his elegant circuits, and in the case of the ACA, those at DIY Audio involved in design production and packaging of kit for these cute little buggers.
Not really a "build" question - I had no issues with mine, other than some confusion over the sequence shown in detailed photos, and since I'm too lazy and inept to conduct a proper forum search, I thought I'd ask here.
I'm looking for recommendations on a similarly budgeted kit for line stage - as opposed to a simple buffer like B1, I'd probably need low gain as some of my DACs or even phono pre-amp have rather low output.
While I'm asking how about something like a DIY version of B4 - realizing of course that's a much more complicated function than a simple 6 Watt Class A amp, and would certainly cost more.
To echo the sentiment -big thanks again to Nelson for sharing his elegant circuits, and in the case of the ACA, those at DIY Audio involved in design production and packaging of kit for these cute little buggers.
What speakers with ACA
Hi,
is ACA´s low damping factor still ok for normal speakers or I should use full range drivers which sounds better with low damping factor?
Hi,
is ACA´s low damping factor still ok for normal speakers or I should use full range drivers which sounds better with low damping factor?
chrisb, check out 6L6's great build-guide thread for a couple preamp ideas. Looks like the BA3 front end and possibly the Bottlehead pre may be up your alley.
I have actually owned an early Foreplay - the current 300B pre-amp is a bit rich for my blood, and as a potentially more synchronistic match for the ACA ( and any future SS amp designs) I was thinking of something very much along the lines of the B3.
This may be well worth further research - fortunately the total "honey-do" list is currently only middle double digit territory, so there may yet be some possibility of more than just thinking about it before the end of this decade😀 I've learned that playing the long game is less prone to disappointment
ACA parts
Anybody has the parts for the kit for sale? Every time I am ready to buy the kit is "out of stock". I have the boards and a nice chassis for it, will build a dual mono in a single box. TIA.
Anybody has the parts for the kit for sale? Every time I am ready to buy the kit is "out of stock". I have the boards and a nice chassis for it, will build a dual mono in a single box. TIA.
Can we add a simple volume control to this amp kit? I dont want another box for preamp, just need a volume control.
I too have been checking the diy store. Maybe time to bite the bullet, print out the bom and order the parts from digikey or mouser. Of course a kit is ideal and that is what I would prefer but I'm late to the party again.
I was hoping somebody had a stash of the extra parts (mostly the fets Q1-Q4, other parts are easier to source locally) but I guess I will have to order through digikey/mouser.
Hello all,
I purchased a power tran with 2x20vac secondary. I want to use this for ACA power supply instead laptop adapter.
I need a circuit for converting AC to DC (19-20vdc), so please advise me
Many thanks,
Huy Navy
I purchased a power tran with 2x20vac secondary. I want to use this for ACA power supply instead laptop adapter.
I need a circuit for converting AC to DC (19-20vdc), so please advise me
Many thanks,
Huy Navy
Varying Feedback
I'm about to start assembly of my ACA boards and hope to run a couple of variations. I will initially build it to spec in breadboard form listen to it for a while. I have Altec 605Bs in open baffles which are 16 ohm drivers. At about 95 db, I suspect the power will be a little low considering the high impedance drivers.
Thus, I was thinking it might be worthwhile altering the feedback to get the output voltage swing up to where I would get the the rated power. Raising the output impedance shouldn't be an issue on the open baffles and may actually help.
It seems obvious that I should raise R12 to reduce the feedback, but I need guidance about altering R11 as the original article indicates they are working together. Is it a ratio thing? And/or should the sum of the two be constant to avoid unbalancing some other aspect of the operation? In initial assembly I want to leave the leads in a configuration that will allow experimentation without torturing the pads on the pcb.
I probably will also play with bridging (as I have four boards and bits). That will surely cure the speaker match/power situation, but I want to try both avenues.
Thanks for your help!
Skip
I'm about to start assembly of my ACA boards and hope to run a couple of variations. I will initially build it to spec in breadboard form listen to it for a while. I have Altec 605Bs in open baffles which are 16 ohm drivers. At about 95 db, I suspect the power will be a little low considering the high impedance drivers.
Thus, I was thinking it might be worthwhile altering the feedback to get the output voltage swing up to where I would get the the rated power. Raising the output impedance shouldn't be an issue on the open baffles and may actually help.
It seems obvious that I should raise R12 to reduce the feedback, but I need guidance about altering R11 as the original article indicates they are working together. Is it a ratio thing? And/or should the sum of the two be constant to avoid unbalancing some other aspect of the operation? In initial assembly I want to leave the leads in a configuration that will allow experimentation without torturing the pads on the pcb.
I probably will also play with bridging (as I have four boards and bits). That will surely cure the speaker match/power situation, but I want to try both avenues.
Thanks for your help!
Skip
Jim's Audio on ebay sells single-rail power supply boards, you add some caps and rectifiers. You can look at the schematic if provided without buying the board to figure out what you need to do. You can also use PSUD program from Duncans Amp Tools to estimate the output using your transformer and choice of caps/rectifiers.
I have 95dB saba greencones and meyer 12" woofers and they get very loud actually. If you have an active sub you could live with the camp amp forever. But I going to try an F4 and F5.
Thanks for the reply! Are your drivers 16 ohm? It's the halving of the power going into that impedance that might put me on the edge. On the other hand, I'm building them to the plan first to find out if I have any issue at all.
Skip
Skip
No, 4, 5 and 8 ohm actually. I am listening to two different tweeters 8 ohm tweeters on either side right now. The Beyma TPL-150 and the Fostex FT17H. Both are really nice. I will use the Pass stuff on 15" midwoofers in the horn system in the future. With a 5W SET tube amp above 300Hz.
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Is value of R15 critical?
Hi. Since there are no kits available at the store currently, I purchased the chassis and the PCBs from the store and sourced the rest of the parts through Digikey. The newer (2013) PCBs come with R15 incorporated into the circuit. I forgot to add that resistor to my order, but I have a couple of 2.7K resistors in my parts box. Would those be OK to use instead of the recommended 2.2K or is the value of R15 critical?
Thanks for any help.
Hi. Since there are no kits available at the store currently, I purchased the chassis and the PCBs from the store and sourced the rest of the parts through Digikey. The newer (2013) PCBs come with R15 incorporated into the circuit. I forgot to add that resistor to my order, but I have a couple of 2.7K resistors in my parts box. Would those be OK to use instead of the recommended 2.2K or is the value of R15 critical?
Thanks for any help.
aha, got it - R15 is later addition for Iq increase
http://www.diyaudio.com/forums/atta...84240737-amp-camp-amp-aca-amp-camp-1b-sch.pdf
2K2 or nuttin'
http://www.diyaudio.com/forums/atta...84240737-amp-camp-amp-aca-amp-camp-1b-sch.pdf
2K2 or nuttin'
Thanks for your reply. I would if there was one or if I knew where it was. R15 is included in the newer AMP CAMP #1b (c) 2013 PCB that I just purchased from the diyAudio store. It appears to be an incorporation of the mod that is illustrated in 6L6's build guide (which he indicated would be included in later versions of the PCB). It is a mod added to Q3.