Planet10 is right about the amp camp mini. Great amp. I've never heard a low watt amp with so much low end magic.
Eico HF81 - built in 1958, Sounds great with high efficiency speakers ... rarely need more than 1 watt to get to 90 dB
Due to limited funds I'm strictly vintage, some that get a near daily play,
Yamaha CA-1000 1974
Yamaha CA-1010 1977
Rotel RX-202 MkII 1974
Sansui AU-505 1972
Luxman SQ-505X 1972?
Most purchased as "parts units" and repaired
A few more in the shed (Yamaha A-1, Pioneer SA-8500II, PL-400,,,)
Yamaha CA-1000 1974
Yamaha CA-1010 1977
Rotel RX-202 MkII 1974
Sansui AU-505 1972
Luxman SQ-505X 1972?
Most purchased as "parts units" and repaired
A few more in the shed (Yamaha A-1, Pioneer SA-8500II, PL-400,,,)
I have a pair of those. 1.5. They are quite. abit older than the ACAmini
Bridged is taking the amplifier in the wrong direction. Rout doubles when the amplfier is bridged, halved with it in parallel.
Your ADS was designed at a time when there where even fewer highish Rout amplifiers could be had. It is expecting a voltage source. Sealed if i remember correctly.
Bass should get looser in bridged mode, in parallel it should get better, but the nature of the sonics between the modes is quite different. I expect that adding or optimizing the speaker’s internal volume damping could improve things at the speaker end. But switch to a voltage amp nd they will likely become leanA bit more radical wwould be converrting to aperiodic.
Zero to do with the power, all due to the lower Rout.
dave
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I have the mono version of that amp. Don’y have access to my tubes thou, supposed to work, and i have it sitting on a lone Jensen to use outside.
dave
Fisher 201... but my Eico Signal tracer is older i listen to it pretty much daily...as it's a signal tracer does it count?
I’ve always been fascinated by these rare beasts and their brethren Sherwood S-6040CP amps from which they were rebadged for Sears. Dual mono, rare Hitachi outputs… Unicorn stuff. 😎 I wonder how they deviate from the more well known topologies of the TO3 and TO3P lateral FET amps.
I built my first transistor audio power amplifier at 1966 ,using germanium PNP power transistor 2SB 337 for output stage, 9012 PNP/9013 NPN pairs for driver, and 9014 as voltage amplifier.
2SB337 has thermo leakage problem, so heat sink is very important during that time.
2SB337 has thermo leakage problem, so heat sink is very important during that time.
I have 2 of the LXI, total cost for both about -$275 (don’t ask), one tweaked up, one waiting. I think i have the schematic.
dave
Not every day, but I have a 1947 GE radio which pulls-in WBZ-AM in Boston better than any newer radio. (Tuned RF stage cuts the IM crap.)
I have a pair of those. 1.5. They are quite. abit older than the ACAmini
Bridged is taking the amplifier in the wrong direction. Rout doubles when the amplfier is bridged, halved with it in parallel.
Your ADS was designed at a time when there where even fewer highish Rout amplifiers could be had. It is expecting a voltage source. Sealed if i remember correctly.
Bass should get looser in bridged mode, in parallel it should get better, but the nature of the sonics between the modes is quite different. I expect that adding or optimizing the speaker’s internal volume damping could improve things at the speaker end. But switch to a voltage amp nd they will likely become leanA bit more radical wwould be converrting to aperiodic.
Zero to do with the power, all due to the lower Rout.
dave
My ACAs were 1.6, so the upgrade to 1.8 was the new back panel... not much else changed. I got four of them... why? Hmm... why not? Everybody needs a bunch of audio amplifiers... Why do I have so many... again, why not?
I recall the ACA Mini, but it was in short supply and so I didn't get around ordering it. Are they going to ship on a regular basis at the diy store?
Anyhow...
Lower output impedance = higher damping huh? That makes a lot of sense. My ICE amps have incredibly taught bass, but the rest is nothing to write about. Perhaps when I get the NCore amps wired in their Ghent chassis, we'll see.
For an old speaker, those ADS L810s ( * ) sound fantastic, actually, with my rebuilt ( ** ) '79 Sansui G-7500, 90wpc, even better than the "higher powered" -also fully rebuilt- '74 Marantz SR-2325 (125 wpc).
The Marantz sounds like Pink Floyd on a rainy winter afternoon, the Sansui sounds like Steely Dan on a summer, sunlit afternoon on the SoCal Coast. It sounds much "faster" and the bass lines are cleaner.... The "High Speed" DC couple power section of the Sansui is exceptional... great voltage amplifier... no power into the Maggies, but excellent with something like the ADS. This is the combo where I burnt a midrange playing Clapton at an 11 setting. But the output transistors are fragile and non-existent. We had to find a used set to replace the originals. I could have gone with a TO-3 (I believe) replacement but that would have changed the sound... defeating the purpose of rebuilding it.
Now, the F5, at less power sounds really good. It won't play as loud, though, but I got older and wiser. Playing at 9 is good enough now.
The ACAs at 8 wpc sound polite, at 16 watts they are a bit more dynamic but the bass gets sloppy. And with those dual 8 inch woofers, it's not good. I really need to find a speaker for those. Maybe build a full range Lowther on a dipole plywood board?
You ought to hear the Sansui crank rock and roll over those ADS L810s. I fall in love with those speakers and then I switch to the Maggies with the A5s and I fall in love again. With the A2, the Maggies have gotten much better, the bass is outstanding, but the entire soundstage, the dynamics, the extension of the treble, the complete lack of graininess, the continuityness of the strings, the "darkness between the notes" that the late HP over at TAS used to wax poetic about...
NOTE: "More on that anon...", remember how often HP would write that?
I might try a pair of Harbeth M30.1s or the equivalent Spendor... much easier to live with, but since my living room is set up to accept the Maggies, and my wife is OK with that... maybe the money will be better spent on a new phono preamp and a new bearing for the LP12?
(*) Yep, the L810s are acoustic suspension designs. Classic walnut boxes on those black metal stands. I'm planning on rebuilding the crossover one of these days... the drivers are fine. I wonder... should I swap the tweeter/midrange in one of them and make them symmetrical? Will that help the soundstaging? Tonally they are fine, but they will not float a soundstage, it is after all a 45+ year old speaker -that I've owned since.
(**) I recently spent some not insignificant moneys to fully rebuild the Marantz 2325, 4215, Sansui G-7500, Kenwood KA3500/KT5300 and Akai AS980. No LED lights... almost everything new, including NOS output transformers. We made a point of keeping the sound the same... but we did put better, lower ESR, somewhat higher capacitance, caps in the power supplies. And, nyet! No LEDs lights.
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Oldest amp still in infrequent use is a Stromberg Carlson AU36B PA amp from the 1940's. It is however powered by "glass-fets."
I sold most of my collection of SWTPC Tiger stuff to another forum member years ago, but I still have a working pair of Plastic Tigers. All of my Tiger stuff was entirely DIY with whatever semis I could get as free samples from Motorola and self made PCB's. Several of us made multiple clones of all but the Tigersaurus for home HiFi, car and van amps, and guitar amps. I had an 8 channel Plastic Tiger system in my 1970's shagmobile van. It also featured a Universal Tiger on the sub-woofer.
I sold most of my collection of SWTPC Tiger stuff to another forum member years ago, but I still have a working pair of Plastic Tigers. All of my Tiger stuff was entirely DIY with whatever semis I could get as free samples from Motorola and self made PCB's. Several of us made multiple clones of all but the Tigersaurus for home HiFi, car and van amps, and guitar amps. I had an 8 channel Plastic Tiger system in my 1970's shagmobile van. It also featured a Universal Tiger on the sub-woofer.
Heresy.... I love the way they are.... did I mention I've owned them since brand new? Back in '78...