Gotchya now.
Yeah, in stereo mode the ACA output imped. is 0.8 Ohm and reminded me, in the bass department, very much of the last (and only) 300B amp I've owned. Volume was fine but it wasn't the most defined. I don't recall what the output impedance was to be able to compare appropriately.
I am enjoying the ACAs in parallel mono mode. Tightened the bass up quite a bit (logical as the output impedance was halved). Going to stuff the rest of the stuffing in the cabinets since I have it on hand. Will find some time to go back to stereo mode and see how it compares.
DIYing this stuff certainly gives one plenty to do on cold and snowy days.
Yeah, in stereo mode the ACA output imped. is 0.8 Ohm and reminded me, in the bass department, very much of the last (and only) 300B amp I've owned. Volume was fine but it wasn't the most defined. I don't recall what the output impedance was to be able to compare appropriately.
I am enjoying the ACAs in parallel mono mode. Tightened the bass up quite a bit (logical as the output impedance was halved). Going to stuff the rest of the stuffing in the cabinets since I have it on hand. Will find some time to go back to stereo mode and see how it compares.
DIYing this stuff certainly gives one plenty to do on cold and snowy days.
PS: This was the amp! Doctorjohn Cheaptubeaudio: Audio Reviews and More: Review: AES SE-1
Can't seem to find the output impedance but the schematic does show a 4 Ohm tap. Not the same but at least it was setup for handling lower impedance speakers.
Can't seem to find the output impedance but the schematic does show a 4 Ohm tap. Not the same but at least it was setup for handling lower impedance speakers.
Tom,
As you've already observed, the output impedance of the amplifier matters. I have tried a number single ended tube amplifiers including 300B designs, and have found them more suitable with speakers with single wide-band drivers. In a couple of systems where the speakers definitely sounded dry and lacked bass response (over damped) with solid state amps, pairing them with a SET seemed to fill up the low frequency regions. However, with other speakers (that were not over damped), the SET amps sounded wooly and lacked both control and slam.
I have not heard the Halcyons, but my gut feel is that a good solid state amp (plenty of DIY options) will drive them nicely.
What is the output impedance and watts of the ACAs in parallel mode?
As you've already observed, the output impedance of the amplifier matters. I have tried a number single ended tube amplifiers including 300B designs, and have found them more suitable with speakers with single wide-band drivers. In a couple of systems where the speakers definitely sounded dry and lacked bass response (over damped) with solid state amps, pairing them with a SET seemed to fill up the low frequency regions. However, with other speakers (that were not over damped), the SET amps sounded wooly and lacked both control and slam.
I have not heard the Halcyons, but my gut feel is that a good solid state amp (plenty of DIY options) will drive them nicely.
What is the output impedance and watts of the ACAs in parallel mode?
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A 300B SE will typically be in the 1.5 to 4 ohm range, so at the best damped end, about the same as bridged ACA.
dave
dave
Z_out = 0.4 Ohm
P = 16W into 4 Ohm; 8W into 8 Ohm.
https://cdn.shopify.com/s/files/1/1006/5046/files/ACA_Monoblock_Operation_RevA.pdf
Just stuffed the rest of the fill in for a total of 2.5 lb per cabinet, 1.25 lb behind each woofer. Might be packed too tight. It flows out to the end of the middle shelf. Easy enough to pull back out and refill. Critical listening later tonight but enjoying just having it on.
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Definitely tightened it up but there is still authority there. Next up is a feet solution that will pay off if it further tightens the already solid imaging.
Shipping estimates
I am really glad you are enjoying the Halcyons! Thanks for the shout out in your very detailed earlier post.
You can get a shipping quote on any of my kits by putting a kit into your cart and starting the checkout process. It will ask you for your shipping info before you put in your credit card. I just charge the actual amount the shipper charges me, and shipping through my store via Shopify is pretty reasonable.
the Halcyon is the heaviest kit I have, at the moment anyway, weighing in at about 110 lbs shipping weight. You will want to have help moving that box around!
I am really glad you are enjoying the Halcyons! Thanks for the shout out in your very detailed earlier post.
You can get a shipping quote on any of my kits by putting a kit into your cart and starting the checkout process. It will ask you for your shipping info before you put in your credit card. I just charge the actual amount the shipper charges me, and shipping through my store via Shopify is pretty reasonable.
the Halcyon is the heaviest kit I have, at the moment anyway, weighing in at about 110 lbs shipping weight. You will want to have help moving that box around!
Hoping to get the feet test mounted this weekend. In the meantime, I'm already thinking of more power. Maybe an F5 is in the works. Dunno but I think I'm hitting the limits on those cute little ACAs.
Tom,
The Pass F5 is a fine amplifier, and many DIYers have had the opportunity to build DIY clones thanks to Mr. Pass's generosity.
Since you are contemplating more power, have you considered something with more watts as in a Class AB design first? (You should definitely build the F5, F6 or M2 some time!)
I built a Class AB amp (link below) a few months back and find it good at driving speakers with sensitivity in the low/medium range.
FH9HVX - Budget Conscious 100w Class AB for Lean Times
This is a fairly easy to build project, and pretty economical too.
The Pass F5 is a fine amplifier, and many DIYers have had the opportunity to build DIY clones thanks to Mr. Pass's generosity.
Since you are contemplating more power, have you considered something with more watts as in a Class AB design first? (You should definitely build the F5, F6 or M2 some time!)
I built a Class AB amp (link below) a few months back and find it good at driving speakers with sensitivity in the low/medium range.
FH9HVX - Budget Conscious 100w Class AB for Lean Times
This is a fairly easy to build project, and pretty economical too.
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Tom,
I just checked the summary of specs for First Watt amps:
FIRST WATT PRODUCTS
On second thought, I would say stick with your plan of building an F5 clone; I had mistakenly thought that the F5 would give 13 watts at 4 ohms (that is actually for the Aleph J which is a single ended amp vs the F5 which is push-pull). The F5 will give you 40 watts at 4 ohms, and the amp has lower output impedance vs the other FW offerings, so damping factor will be higher. However the gain is 15dB, so ideally you will need a preamp with some gain.
I just checked the summary of specs for First Watt amps:
FIRST WATT PRODUCTS
On second thought, I would say stick with your plan of building an F5 clone; I had mistakenly thought that the F5 would give 13 watts at 4 ohms (that is actually for the Aleph J which is a single ended amp vs the F5 which is push-pull). The F5 will give you 40 watts at 4 ohms, and the amp has lower output impedance vs the other FW offerings, so damping factor will be higher. However the gain is 15dB, so ideally you will need a preamp with some gain.
Thanks for the inputs. I've migrated from building vacuum tube kits to the solid state variety so I'm still learning. Many similarities but many differences as well. With the love of simple tube circuits, I'm enthralled with the Pass designs. So, yeah, the F5 is on my mind. Maybe the F6. But, I keep taking on endeavors that many times seem to have no end. (of which, audio as a whole is one of those.) So I'll keep cogitating on it and, in the meantime, put on some albums and just not turn it up quite as much (even though these Halcyons love it as pointed out by Alan).
In the meantime, I'm working on mounting those fancy IsoAcoustic feet and upgrading the speaker cables to see what that gets me. Yes, neverending...
In the meantime, I'm working on mounting those fancy IsoAcoustic feet and upgrading the speaker cables to see what that gets me. Yes, neverending...
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From the amps to the speakers, maybe some Goertz ribbon cables or one of the inexpensive offerings from Analysis Plus. Nothing too fancy but better than lampwire stuff from the hardware store. I'm still running handwoven strands of 4x20ga. hook-up wire. Looking more to get something that is meant to handle current. The nice thing is I can move the amps closer to the speakers, shortening up the cable runs needed. Going to end up paying more for the spades and termination labor than the fancy-dancy wire is worth.
Do try a pr of single strands from a CAT5/6 cable and let us know how it works in your system. If you are lucky you could save enuff to take the wife out for dinner at a fancy restaurant.
dave
dave