SDA1 Efficiency
Zen Dragon
Posts: 501
Hi All.
I have been absent from the forum for some time after a move to CA, new job, settling in. Stuff like that. I have been from an audio perspective more focused on tube audio than speakers for a time as I got my first tube amp Antique sound labs AQ-1002 about a year ago. I am very close to having learned enough (dangerous stage) that I want to try to build my own Single ended Triode amp. At any rate I have owned the SDA-1C'c for several years and love them. They are generally regarded as the preferred in the SDA-1 series as they were the last rev in the series.
Now however with low power SET's possibly on the horizon I am looking at efficiency. I know the SDA-1C's are 90 db and I have seen that the 1A's are 95 db. Now what's a few DB between friends? Well at low power rather significant. Is there a noticeable drop in overall sound quality from the SDA-1C's to the SDA-1A's. The 1A's are a much better efficiency match for a lower power tube amp, especially since I do prefer some volume.
Would love to hear opinions. I remember F1 to be an especial SDA guru.
Thanx
Brian
I have been absent from the forum for some time after a move to CA, new job, settling in. Stuff like that. I have been from an audio perspective more focused on tube audio than speakers for a time as I got my first tube amp Antique sound labs AQ-1002 about a year ago. I am very close to having learned enough (dangerous stage) that I want to try to build my own Single ended Triode amp. At any rate I have owned the SDA-1C'c for several years and love them. They are generally regarded as the preferred in the SDA-1 series as they were the last rev in the series.
Now however with low power SET's possibly on the horizon I am looking at efficiency. I know the SDA-1C's are 90 db and I have seen that the 1A's are 95 db. Now what's a few DB between friends? Well at low power rather significant. Is there a noticeable drop in overall sound quality from the SDA-1C's to the SDA-1A's. The 1A's are a much better efficiency match for a lower power tube amp, especially since I do prefer some volume.
Would love to hear opinions. I remember F1 to be an especial SDA guru.
Thanx
Brian
The Family
Polk SDA-1C's
Polk SDA-2
Polk Monitor 10B's
Polk LSI-9's
Polk Monitor 5's
Polk 5 jr's
Polk PSW-450 Sub
Polk CSI40 Center
Do not one day come to die, and discover you have not lived.
This is pretty f***ed up right here.
Polk SDA-1C's
Polk SDA-2
Polk Monitor 10B's
Polk LSI-9's
Polk Monitor 5's
Polk 5 jr's
Polk PSW-450 Sub
Polk CSI40 Center
Do not one day come to die, and discover you have not lived.
This is pretty f***ed up right here.
Post edited by Zen Dragon on
Comments
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Also, along the same lines of efficiency, does anyone know what makes the SDA-1A 5 db more efficient than the SDA-1C? I would think the crossover must be the biggest contributor.
Any thoughts?The Family
Polk SDA-1C's
Polk SDA-2
Polk Monitor 10B's
Polk LSI-9's
Polk Monitor 5's
Polk 5 jr's
Polk PSW-450 Sub
Polk CSI40 Center
Do not one day come to die, and discover you have not lived.
This is pretty f***ed up right here. -
Any SDA with a pin/blade connector, and 6ohms will be less efficient than the blade/blade speakers. Also the pin/blades send the SDA info via the ground to the opposing speaker.Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
Thanks
Ben -
Hey Zen,
You may find the sound of the 1A's to be quite different than what you're use to because of the dimensional tweeter and the 2 "bass drivers." The SDA SRS will sound closer to your 1C's and with an efficiency of 93dB should work with one of the higher powered SET amps.
The crossover and drivers used make the difference.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Thanx for the response F1. Problem is, there's never a pair of SRS's laying around when you need one.
I don't think I can sneak that in the budget. The 3 pairs of matched 300B's i orderred assures me of that. I am darn curious now how the SDA-1A would sound. I mean, it's a question of a point of balance I would think. I mean word on the street is single ended triodes can tame the horn of a Klipsch, (didn't mean to curse) and that's no small task (my ears hurt just thinking about them on solid state)
So the difference from the 1-A's to the 1-C's I would imagine is much less, and the difference might be an easy tradeoff for the 5db gain in efficeincy.
Man I wish I still had my house in WA with the living room and the family room. This would be an easy decision, 1A's, 1C's......Both.
Have any of the forum members listened to a single ended triode amp through a pair of SDA-1A's?The Family
Polk SDA-1C's
Polk SDA-2
Polk Monitor 10B's
Polk LSI-9's
Polk Monitor 5's
Polk 5 jr's
Polk PSW-450 Sub
Polk CSI40 Center
Do not one day come to die, and discover you have not lived.
This is pretty f***ed up right here. -
I have to ask, what are you going to do with 3 matched pairs?
The main difference has to do with the use of the dimensional tweeter as it can add a somewhat phasey effect to some folks.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
I just hate doing things in a small way, so i am going to attempt 3 parallel on each side with a goal of about 20W. There are plenty of 2 parallel per channel designs out there, and I just couldn't resist going for a third. I know from a power perspective the gain is not particularly relevant, but I'll let my ears decide. I will be using adjustable negative voltage to set the bias, so I can easily pull one tube each side out, reset the bias and see how it sounds with just 2 on each side. Not quite that simple with all the impedance matching on the O/P tranny, but I have tube cad software on the way to help me out. I wore a groove into the buttons on my calculator and broke down and purchased the software this week.The Family
Polk SDA-1C's
Polk SDA-2
Polk Monitor 10B's
Polk LSI-9's
Polk Monitor 5's
Polk 5 jr's
Polk PSW-450 Sub
Polk CSI40 Center
Do not one day come to die, and discover you have not lived.
This is pretty f***ed up right here. -
F1 I just had to pick up a local pair of SDA-1A's and hear for myself. There was a pair local I got for $280, no interconnect, and some wear on the grills, but I thouht I'd give them a spin. As Henry David Thoreau might say
" If the SDA-1A's proved to be mean, why not get the whole and genuine meanness of them, and publish their meanness to the world, of if they were sublime, to know it by experience, and be able to give a true account of it"
Well, the SDA-1A's are not mean, but neither are they sublime. You were correct in that they have a much different sound then the 1-C's. The highs are not as liquid or clear. The highs are a bit darker and perhaps a bit veiled. The bass is accentuated more than the 1-C's, and can get a bit boomy. The timber from the mids up to the highs is a bit darker. Overall I find for my tastes the SDA-1C's are the better speaker for me.
It is one thing to read about the differences between speakers, and quite another to hear them. It is very likely I will let these go, as they do not timber match the rest of my system t all.
Just thought I'd share my impressions with the community.The Family
Polk SDA-1C's
Polk SDA-2
Polk Monitor 10B's
Polk LSI-9's
Polk Monitor 5's
Polk 5 jr's
Polk PSW-450 Sub
Polk CSI40 Center
Do not one day come to die, and discover you have not lived.
This is pretty f***ed up right here.