ACA v1.6 Balanced Monoblocks - Speaker Loading Resistor
Hi,
Just read Herb Reichart’s Stereophile article on the First Watt SIT-3. In it Mr. Pass recommended adding a 10 ohm speaker loading resistor shunt to the speaker binding post to improve the sound coming from the SIT-3 when running with Zu Audio Soul Supremes (pretty effiecient speakers). (Article is here First Watt SIT-3 power amplifier Page 2 | Stereophile.com )
I am running the ACA v1.6 Balanced Monoblocks 24 volt supply with Zu Soul Superflys. Just curious if it makes sense that the sound would be improved by adding a similar shunt.
Thanks for any info you can provide.
Jim.
Hi,
Just read Herb Reichart’s Stereophile article on the First Watt SIT-3. In it Mr. Pass recommended adding a 10 ohm speaker loading resistor shunt to the speaker binding post to improve the sound coming from the SIT-3 when running with Zu Audio Soul Supremes (pretty effiecient speakers). (Article is here First Watt SIT-3 power amplifier Page 2 | Stereophile.com )
I am running the ACA v1.6 Balanced Monoblocks 24 volt supply with Zu Soul Superflys. Just curious if it makes sense that the sound would be improved by adding a similar shunt.
Thanks for any info you can provide.
Jim.
Hamelka, I’d like to know as well.
I have the Zu Omen DW and made the ACA monoblocks for them. I didn’t love them with the Zu’s...and preferred them with my KEF floorstanders. The opposite was true for my PrimaLuna Dialogue 2. That amp didn’t do my KEFs justice but it pairs nicely with the Zu’s.
The ACA’s with the Zu had more bass (perhaps a bit boomy), but the soundstage suffered and the highs were a bit harsh.
I have the Zu Omen DW and made the ACA monoblocks for them. I didn’t love them with the Zu’s...and preferred them with my KEF floorstanders. The opposite was true for my PrimaLuna Dialogue 2. That amp didn’t do my KEFs justice but it pairs nicely with the Zu’s.
The ACA’s with the Zu had more bass (perhaps a bit boomy), but the soundstage suffered and the highs were a bit harsh.
It's a 16ohm 10W in the article.
SQP10AJB-16R Yageo | Mouser
Give it a try, it's going to cost less than $2. (Before shipping... 🙂 )
Thanks 6L6 for the prompt response. I’ll give it a shot. Is it just as simple as connecting each terminal of the resistor to each of the binding posts? Anything else I should be concerned about? 16ohm 10w, you got it right.
Thanks again.
Jim.
Thanks again.
Jim.
Totem mini speakers with ACA ?
Hello,
I have a question regarding Amo Camp Amp and Totem Mini speakers.
Does anyone have this combination? Will this combo work well? It’s 87db 8 ohm speaker and my room is 16’ x 12’ x 9’ ceilings. I am just worried the 8 wats won’t be enough to drive these.
Thanks
Hello,
I have a question regarding Amo Camp Amp and Totem Mini speakers.
Does anyone have this combination? Will this combo work well? It’s 87db 8 ohm speaker and my room is 16’ x 12’ x 9’ ceilings. I am just worried the 8 wats won’t be enough to drive these.
Thanks
I'm going to take a stab at this. It'll depend on your preamp.
If you have a zero-gain pre like I had at first in the shape and form of a B1, then no, it won't be loud enough with the 87dB 8 Ohm speakers. If you use a pre with some gain (15dB should work quite well), then I guess you'd be happy with the sound, even though it's only 8W.
If you have a zero-gain pre like I had at first in the shape and form of a B1, then no, it won't be loud enough with the 87dB 8 Ohm speakers. If you use a pre with some gain (15dB should work quite well), then I guess you'd be happy with the sound, even though it's only 8W.
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Thanks Skylar88. I do have pre amp (12AX7 based) with gain and I do drive them with single ended EL 84 amp, (5-6w)but was not sure if the 8W solid state will be strong enough.
( by the way I said the speakers are mini, actually it’s TOTEM MITE model)
Thanks again.
( by the way I said the speakers are mini, actually it’s TOTEM MITE model)
Thanks again.
If you have a SE EL84 amp and it drives them to levels you are happy with, the ACA will do as well or better. 🙂
The ACA is single-ended and has a grossly oversized PSU, giving it clipping characteristics very much like a SE tube amp.
The ACA is single-ended and has a grossly oversized PSU, giving it clipping characteristics very much like a SE tube amp.
Even better, build two 😉
The stock ACA has quite remarkable performance, and it also has simple options for expanding its capability when used as monoblocks.
For those who are willing to color outside the lines a little bit (or a lot), it is capable of even more.
I completely agree with the above, ( and not because it will sell another amp ) - the ACA in self bridged mode (driven from the RCA jacks) has the perfect dose of negative-phase 2nd harmonic that is the "magic sauce" that so many people love and enjoy.
This is not to cast any negatives on a single ACA - it's just that 2 is greater than the sum of it's parts, as you get more power AND an increase in overall beauty.
Makes for an no-brainer upgrade path. 🙂
This is not to cast any negatives on a single ACA - it's just that 2 is greater than the sum of it's parts, as you get more power AND an increase in overall beauty.
Makes for an no-brainer upgrade path. 🙂
Thanks, Tungstenaudio and 6L6. Will consider.
Would you know if 250VA 18v+ 18v toroidal transformer be good enough to run both ACA amps? I can fit both in my chassis.
(Was gonna build my own PS... and a buy just the ACA parts kit, I have a chassis)
Would you know if 250VA 18v+ 18v toroidal transformer be good enough to run both ACA amps? I can fit both in my chassis.
(Was gonna build my own PS... and a buy just the ACA parts kit, I have a chassis)
Based on what I have been doing lately, a 250VA 18V + 18V transformer will be sufficient for one ACA. A pair of monoblocks would need two of these.
Since a linear PSU does not include power factor correction, as the usual ACA kit SMPS does, the transformer needs a higher current rating to make up for the fact that it is only able to charge the reservoir capacitors during a small portion of the AC power cycle.
Since a linear PSU does not include power factor correction, as the usual ACA kit SMPS does, the transformer needs a higher current rating to make up for the fact that it is only able to charge the reservoir capacitors during a small portion of the AC power cycle.
The above is true, but the ACA, being single-ended class-A has a constant draw on the PSU regardless of output.
I ordered 2 kits to begin with and very glad I did.
Did try one of them in stereo while building the 2nd, and believe it, 2 ACA's is 3x better than one.
Math may be fuzzy, but the sound is clean and delightful.
Did try one of them in stereo while building the 2nd, and believe it, 2 ACA's is 3x better than one.
Math may be fuzzy, but the sound is clean and delightful.
Ok, my system is with the latest ACA, the AKSA preamp, and running the Rogers LS7.
The problem is that with the music running at normal sound, the volume is at around 80% and if I make it a little higher volume the speakers is crackling the tweeters. Swapped it back with the original MusicalFidelity P150, and none of that crackling.
I'm sure that running the volume at the top will be damaging the tweeters etc, and don't want to hear it crackling! Not enough amp spare for the ACA and the Roger LS7.
So, I need to give it a better Amp. With a double ACA, how much extra power would it be for the system before the crackling again?
Any other Amps I should be looking for? Have seen the MoFo, anything else?
Are you talking about a bridged ACA or a normal ACA? 250VA seems high for the latter, 80VA is what usually is recommended.
Why not try the ACA in bridged mode? That should get you about 15 watts into 8 ohms. OK it will only be mono, but you will know if it will drive the LS7s to an acceptable level. (Just do not expect twice as loud for 2 times the watts...)
Go from there.