But you have to start somewhere. At least both of you have taken the first and second steps: starting the project, and realizing that new skills and tools are needed. Good for you! Don't give up but forge on. Get a minimal set of tools, and perhaps one or two practice kits. I regret the loss of Radio Shack, because they had numerous kits that you could have practiced on. But I think that ther are lots of stuff out there on the web, so find something and go to it. If I had a suggestion on type of kit to practice basic soldering, it would be something like a simple flasher or tone buzzer kit, that has an absolute positive indication that it is working (it flashes/sounds).
I wonder if there is a basic guide for beginners somewhere on this forum?
I bought a couple of ACA "redux" to play with. Those are as simple as it comes. I mean, I can solder simple circuits for my Raspberry, but those are digital/logic stuff and don't require biasing or anything fancy.
Radio Shack... ah yes... and Dynakits and Heathkits, I built those. Back in the day I was a bad boy with the soldering iron in the Physics Labs and at work in the metrology lab.
Heck, I still have my mid 70s analog Rat Shack DMM.... I never burnt it. But, I need to buy a couple of Flukes... and likely a 200 Mhz, 2 channel scope, function generator and a nice power supply. It is, after all, a excuse for more toys.
Sorry, I underestimated your experience! You know, tweaking is for young people with hearing to match, IMO. I am so sorry to say that at 67, my high frequency hearing response has dropped off a cliff. How do I know? When I listen to CDs where I expect to hear a musical element that is of high frequency and it ain't there! Example: tambourine played off-meter in the song, Mr. Zero, by Bob Lind on that incredible first album of his. The shimmer of riveted cymbals on the intro of the Association song, "Never My Love." And on and on. Plus, tinnitus masks a lot of low level detail. And I tried to protect my hearing: stopped going to rock concerts for the most part when I was in college (1973-77). Limited headphone use from about 15 years ago to listening while exercising, and making sure volume was well down. Haven't used headphones in 8 years, I'm estimating. For me, the action is in the midrange - clarity and articulation there, and in the bass.
No problem.... no need to be sorry about anything. I'm rusty.
Even though our hearing goes a bit "south" with age, you can still hear the shimmering of stuff like the crash hat, cymbals, triangle, bell, etc...
The last rock concert I went to was Billy Idol back in the mid 80s... saw lots of fine punk and new wave bands in Hollywood and The OC at one point, but I decided that I prefer classical and acoustic music for live performances.
(Note: you want harmonic distortion? How about distortion of all kinds... harmonic, disharmonic, even, odd, saw tooth waves.... you name it. Those slam punk'ing nightclubs required 20% distortion just to get the action going...)
Over time my systems have progressed to ever lower noise floors, so that volume is not needed to hear the music. The days when I cranked it up to 11 and felt the bass in my gut are long gone. I don't want that. Even rock doesn't have to be loud when the noise floor drops. Even my HT set up has also gotten less noisy so I don't need no stinking subwoofers... in my systems, I have achieved great microdynamics....
... Just as Nelson Pass talks about the First Watt, Harry Pearson (TAS) used to muse about low resistance to starting movement from a rest position ( what we'd call low static friction ). So that speakers, and devices, can move freely from a stationary point without requiring "extra" motive force... which is a distortion. This also affects electronic systems - minimized in a tube SET ofrSS Class A.
When a system exhibits very low static friction, then it's in linear movement from very low levels.... there is no "hump" in power to get the mechanisms moving, hence very low noise.
Now, unlike Nelson's idea of First Watt, this is not always the case... for example, my Maggies go nowhere unless you got 10 watts to take them out.. but they are very linear... conversely -?- I got some 85 db minimonitors ( two brands ) that do very well with only 10 watts...
So, IMHO, the action is in lowering the noise floor, lowering the static friction of a system and ensuring micro and macro dynamics with peaks not exceeding 100 db... hopefully just 95 db.
Who would have known, when we were young, that you could have accurate bass at 95 db?
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Just completed my ACP+ and realized that I forgot to order my headphone jack. Kinda would like to wait to order it until I need some more parts. Will the circuit work without the jack or will I need to temp jumper wires in place of it?
The circuit will work without the jack as the default output is to the RCAs on the rear (i.e.: the headphone adaptor is really a little 2-way switch, and when you do not have the 1/4 jack installed, the in/out pins are connected. When you insert the jack, it lifts the contacts off and connects the outputs to the 1/4 points. You will have to temporarily jump the "in/out" pins for the L and R to be connected as the switch would connect them when clamped down (i.e.: no 1/4 inserted). If this sounds confusing, feel free to DM me or just wait until your connector arrives. 🙂
is there any chance to increase the acp+ gain to 26db and output voltage to drive the sit power follower amp?
The limited edition SIT power follower amps that diyAudio sold by lottery, used Sony VFET devices from Nelson Pass's personal supply. Those amps required 14V RMS at the RCA input, to deliver full output power. Running through the math, 14V RMS is a sinewave with 39.6 volts swing from peak to trough. So your DIY preamp would need to operate from a power supply whose total voltage span, between bottom_supply_rail and top_supply_rail, is at least 45 or 48 volts.
The other way to skin the cat, is to use a step-up transformer as the final output stage of your DIY preamp. This is the approach Nelson Pass took in the lottery batch of 200 Sony VFET amplifiers. He selected an Edcor 1-to-5 step up transformer, meaning that the required preamp swing is only (14 / 5) = 2.8V RMS ... which is just 8 volts from peak to trough. Your DIY preamp could achieve that when running from a total supply voltage span of just 15 volts. IF you are able to purchase Edcor transformers. They are assembled and shipped from USA. European distributor "Don Audio" offers them as well.
Hello
Completed my ACP+. Very satisfied with the result both appearance and sound quality. Made some minor changes. Both C1 and C3 are bypasses with 0,1 uF Wima, between PCB and ground plane, and C3 is replaced with Elna Silmic II. No particular reason for the change, but more that I feel that use of decoupling capacitors make sense and I like Simlic. I do not use the supplied wall-mount PSU, but the PSU from the ACA mini kit. ACA mini, when finished, will have PSU from Meanwell 24v/5A. Both amps will have SMPS DC filter,P089ZB.
In summary
Very happy with the sound quality from ACP+ and looking forward to completing the set-up with ACA mini. Speakers are Klipsch Heresy and hopefully it will make a nice combo with these amps.
Completed my ACP+. Very satisfied with the result both appearance and sound quality. Made some minor changes. Both C1 and C3 are bypasses with 0,1 uF Wima, between PCB and ground plane, and C3 is replaced with Elna Silmic II. No particular reason for the change, but more that I feel that use of decoupling capacitors make sense and I like Simlic. I do not use the supplied wall-mount PSU, but the PSU from the ACA mini kit. ACA mini, when finished, will have PSU from Meanwell 24v/5A. Both amps will have SMPS DC filter,P089ZB.
In summary
Very happy with the sound quality from ACP+ and looking forward to completing the set-up with ACA mini. Speakers are Klipsch Heresy and hopefully it will make a nice combo with these amps.
Attachments
I've heard good reports with the Klipsch Heritage speakers and the ACA's. That's where I'm heading. Building a ACP+ next snow storm to add to my ACA monoblocks.
Then we have finished building ACP+ and ACA mini. ACP+ is operational while ACA mini is adjusted and waiting adapter for speaker connection.
https://www.amazon.com/Kinter-LilPiggies-Adapters-Amplifier-Connections/dp/B07W7MPHWB
https://www.amazon.com/Kinter-LilPiggies-Adapters-Amplifier-Connections/dp/B07W7MPHWB
Fun stuff without the chassis. If I didn't have two regular ACA's I'd build the mini to go with the ACP+ full nudie.