[macdane]

Here's the deal. My primary speakers are single-driver Super 3S from Omega, driven by Wright Sound WPA-3.5 2A3 amps. Lovely sound in all regards but one: no matter how you slice it, there's just no real bass.

I have a pair of Fried D/2 subs sitting idle at the moment, but they have no crossovers (don't ask). It seems to me that this could be a great solution if I could find a competent stereo amp for them. I'm of course thinking of a dedicated subwoofer amp with built-in crossover controls; I'd run the Omegas full-range and just augment the bottom end a bit.

Audiogon has a Paradigm X-850 that may be what I need -- if a bit over the top -- but I'm having trouble discerning whether it's a stereo amp or simply a mono amp designed to drive two subs. With that bit of background, any thoughts?

Thanks!
Dane

[srb]

If you don't need a whole lot of power and just need to augment the bottom end a bit for music, the Dayton Audio APA150 75W/ch stereo amplifier with 50-150Hz low-pass filter might work for you.  4 Ohm Class A/B with toroidal transformer, it does have a fan but users say it rarely comes on and when it does that it's quiet.

Under $160 with free shipping and 45-day return, you'd only be out return shipping if it didn't work out.

Steve

[macdane]

Thanks, I'll look into that. 75 w/ch is more than enough!

[csmgolf]

I have a pair of C3/L with D2s that are in the process of a major overhaul. I have removed the stock crossovers for the subs and bought a pair of plate amps for them. It will require building a small enclosure on the back panel to avoid having the amp in the transmission line. I found a pair of plate amps on EBay made by Apex that will fit neatly within the confines of the panel that are 100 watts each into 8 ohms and 150 into 4 ohms. I have not gotten to the point of using them yet, as the project is on going. They look to be pretty well built and were $220 for the pair. With a little time, skill, and effort, a long term solution is there to be had for your D2s. Good luck.

[macdane]

Ok, so I sort of impulsively ordered two of those Dayton amps last night.

Since my preamp only has a single set of outputs, I'm thinking of splitting those with something like the Audioquest RCA splitter and then running one set of interconnects to the subs and one set to my main amps. Any reason not to do it this way? If so, how would you do it?

Thanks!
Dane

[srb]

Why are you using two amplifiers (you did say you ordered them impulsively  )?  I don't know what the impedance of the Fried subs are, but keep in mind if your plan is to run each stereo amp in mono bridged mode with each amp powering one subwoofer, they are only rated for bridged operation into an 8 Ohm load (as each bridged amp sees half of the actual impedance).

Many people do use splitters off of the preamp outputs as you propose and for many it does work, but you are connecting amplifier inputs together in parallel and reducing the input impedance that the preamp sees, so you'll just have to see if the particular combination of your preamp's output impedance and the input impedance of the two paralleled amplifiers audibly affects the sound.

Steve

[macdane]

Yep, more impulse than anything else. They're so cheap, it was easy to just say "why not?"

As I recall, the Fried subs are a pretty benign 8 ohm load. As you say, listening will tell. The most significant issue I face now is making room for them alongside the Omegas.

In the event that it doesn't work well as I described, how would you suggest connecting everything?

Thanks,
Dane

[srb]

Splitting the preamp outputs is the only option for your existing setup.

You could get an accessory speaker to line level converter box that attaches to the speaker outputs of the main amplifier and provides RCA outputs to the subwoofer amplifier(s).  They are a high impedance (resistance) load so they should have little effect on the comparatively low main speaker impedance, much like the speaker inputs on many subwoofer plate amplifiers.  They do use resistors that dissipate a small amount of power, so you have to make sure that the convertor has a similar wattage rating as the main amplifier.

But hopefully, the splitters on the preamp outputs will work fine.  It would be interesting to see how a single Dayton amp performs in your setup compared to using both amplifiers bridged, if in fact the subwoofers are 8 ohms as you recall.

Steve

[macdane]

If I'm reading things correctly, another option would be to run one set of interconnects from my preamp to the Dayton amp, then another from the line-level outputs on the amp to my primary amps. Right? I don't like the idea of inserting extra gunk in the signal path but I think that should work ... and eliminate the need for two long runs of cable between the preamp and the amps.

Since my first two attempts to locate my RCA splitters in the basement have been fruitless -- and the amps are due to arrive in the morning -- this may very well become Plan A. I'll definitely try a single stereo amp first and let you know how it does. These subs (along with the matching C/3L speakers) really rattle the walls when driven by my wife's little 35 wpc Luxman receiver, but that's one hell of a 35 wpc ... I've also driven Apogee Stages with it. I guess we'll see what these Dayton amps are made of!

[srb]

Yes, that would also work.  The line outs on the Dayton amp appear to be full-range even if the low-pass filter is engaged.  I don't know if running the main signal through them would muck things up much or not, but you can always compare to splitting directly off of the preamp outputs should you later locate the splitters.

Steve

[Poultrygeist]

I used the same Dayton amps to drive a pair of efficient H-frame subs ( Alpha 15As ) augmenting my full range speakers but never got quite the power I was looking for.

I switched to a couple of cheaper Yung class D plate amps and now I get all I need and then some.

The Yung plate amps mounted in simple wooden frames are ideal for outboard sub power solutions and their crossover goes to 40hz whereas the Dayton stops at 50hz. The output on the Dayton is a pass through so you can daisy chain them together. You can gain a little more power by splitting the source with Y cables.

The manual that comes with the Dayton is lacking but there's a better one on the Emotiva site ( the BPA-1 is the same as the Dayton ).

[Poultrygeist]

This may be similar to what you plan to do. I'm using a 2a3 amp for the Tektons running full range and  two Daytons with crossovers driving the H-frame subs.

[macdane]

This may be similar to what you plan to do. I'm using a 2a3 amp for the Tektons running full range and  two Daytons with crossovers driving the H-frame subs.

Yes, Poultrygeist, that's very similar to what I'm doing. In a nutshell:

Sources (Sony SACD and Well Tempered via a PS Audio Phonolink) and preamp (actually a Meier Corda Prehead) are around the corner in another room. They'll be connected to the Dayton amp(s) by a long interconnect run. The Dayton(s) will drive the Fried subs while their line-level outputs carry on to the Wright 2A3 amps driving the Omegas.

If these Dayton amps have any guts at all, they should easily handle the Frieds. If not, I do like the idea of lowering the cutoff to 40Hz. We'll see soon! Everything is in place awaiting the UPS driver. I've been listening for the past two hours and the tubes are nice and warm ... I should be able to get a Dayton inserted and playing within a minute of unpacking for a quick comparison. Stand by!

[Rusty Jefferson]

Here's an option I used for a period of time in my system.
http://www.roundsound.com/sub-woofers/reference-sa-amp.html

It's very effective. Built in crossover, eq, phase, and about 150 watts per at 8 ohms, Stereo. Best of all, you can use speaker level inputs instead of interconnects, thereby eliminating sound degradation. Pretty common on Audiogon for $4-500.

[Poultrygeist]

Per the manual two Daytons in bridged dual mono ( RCA inputs split between the two ) is said to deliver 150 watts into 8 ohms. You'd think that would be plenty but I wished for a little more with 91db woofers. You may find it's enough for your box subs.

The nice thing about buying from PE is their no questions asked return policy.

[mjosef]

Been using this Crown, xti1002, for about a year now to power my bass. Stable down to 2ohms, 3year warranty. Price 499.
Stereo Wattage: 700W @ 2 ohms, 500W @ 4 ohms, 275W @ 8 ohms.
DSP input for Xover, EQ, etc
 http://www.sweetwater.com/store/detail/XTi1002

[ohenry]

I also use a crown amp, but from their XLS line.  They're class D, very flexible in use, lightweight and have a built-in crossover.  The only thing lacking is a phase switch.  I have an XLS2500 that'll drive 2400 watts into 4 ohms (bridged).  The XLS1000 and XLS1500 are enough to rock the house as well and are pretty inexpensive.

It's hard to beat class D bass. 

http://www.crownaudio.com/xls-drivecore.html

[macdane]

I should be able to get a Dayton inserted and playing within a minute of unpacking for a quick comparison. Stand by!

Yep, that was me about 3.5 years ago. I hope reviving this thread isn't some sort of no-no ... I just figured it's all related and it might help to have the original contributors notified. And yep, I kinda disappeared after that post, for a couple of reasons. At first, silly as it may sound, I vanished because everything sounded so dang good that all I wanted to do was listen to music. I then developed what I thought was a tube problem (it wasn't, but that's another story). While wrestling with that my SACD player bit the dust, and I left my system to gather dust for a couple of years.

I recently inherited an unwanted MacBook Air and decided to get things cooking again. I bought a used Hegel H80 integrated amp (75wpc) and while awaiting delivery I got the old system fired up again. The MBA was feeding a Meier Corda Prehead via a Meridian Explorer. The Prehead was then connected to the two Dayton APA150 amps driving my Fried subs, and then the line level output of the Daytons fed my Wright 2A3 mono amps (3.5wpc) driving the main Omega Super 3S speakers. After a simple matter of tuning the crossover point and output level of the Daytons, pure magic came out. Are you with me?

Ok, when the Hegel arrived yesterday morning, I slipped it into the system in place of the Prehead (still using the Explorer as DAC, but a USB cable is on its way so I can try out the Hegel's built-in DAC). The Hegel drives the Omegas, and the Hegel's pre-out goes to the Dayton/Fried subwoofer department. Easy peasy, right? And in addition to getting those pesky tubes out of the system, I have the bonus of no longer having the Dayton amps in my main signal path to the Omegas.

The problem is ... there's no bass. The volume controls on the Dayton amps are at maximum, and with most music I literally have to feel the sub drivers to tell if they're doing anything at all. The subs DO play, and their output DOES track with the Hegel's volume control, but at any given volume the output of the subs is so far below that of the main speakers as to be utterly useless. There's nothing unusual about the Daytons' input sensitivity (1V), so I'm left to assume that either (a) there's something deficient about the pre-out on the Hegel, or (b) the sound output from the 150wpc Daytons/88-89dB(?) Fried subs simply can't compete with that of the 75wpc Hegel/94.5dB Omegas.

I'm not equipped to do the technical stuff, but it seems that if the Hegel is feeding the same signal to the Daytons as it is to its own internal amp, the ~6dB difference in speaker sensitivity would mean I need 4x as much power for the subs as for the Omegas ... is that correct? Well, I only have 2x the power. Is this as simple as sticking a 400wpc Crown amp in there in place of the Daytons, or am I missing something?

Thanks for your patience if you made it this far!

Dane

[RDavidson]

I think you’re probably correct. Your Omegas are likely using just a hand full of watts, probably 2-3 at most times. So, at such a low volume setting on your Hegel your Dayton amps are not getting enough voltage gain to drive the much less sensitive Fried drivers. In essence, the Daytons are likely only receiving small fractions of 1V....not nearly enough to reach their full power rating. Amps with more power won’t likely make a single bit of difference. You need to look for sub amps that have lower input sensitivity, but less than 1V is really quite low. I’m not sure you’ll find what you need going that route. I suggest talking to Louis at Omega about this. I’m sure he’s helped others with this issue. Maybe a simple solution would be to try and attenuate the gain from your source with something like Harrison Labs attenuation plugs. What this would do is allow you to "open up’" the Hegel’s volume control a bit more and thus provide more voltage gain to the Daytons. There’s a few other solutions, but dealing with voltage gain is sort of a complex issue. The further you dig into this, the more you will understand how important amp/speaker matching is, not just from an audible standpoint, but from the often overlooked / and often misunderstood electrical standpoint.

[macdane]

I think you’re probably correct. Your Omegas are likely using just a hand full of watts, probably 2-3 at most times. So, at such a low volume setting on your Hegel your Dayton amps are not getting enough voltage gain to drive the much less sensitive Fried drivers. In essence, the Daytons are likely only receiving small fractions of 1V....not nearly enough to reach their full power rating. Amps with more power won’t likely make a single bit of difference. You need to look for sub amps that have lower input sensitivity, but less than 1V is really quite low. I’m not sure you’ll find what you need going that route. I suggest talking to Louis at Omega about this. I’m sure he’s helped others with this issue. Maybe a simple solution would be to try and attenuate the gain from your source with something like Harrison Labs attenuation plugs. What this would do is allow you to "open up’" the Hegel’s volume control a bit more and thus provide more voltage gain to the Daytons. There’s a few other solutions, but dealing with voltage gain is sort of a complex issue. The further you dig into this, the more you will understand how important amp/speaker matching is, not just from an audible standpoint, but from the often overlooked / and often misunderstood electrical standpoint.

Thanks for the reply. You're right about Louis, and he's the first guy I called ... I've spent a total of about an hour on the phone with him and he wants to help but says he's never encountered this. It appears most Omega customers tend to go with Omega subs, which he builds using plate amps with high level inputs ( the Daytons' inputs are line level). He's actually the one who suggested a more powerful amp like the Crown, but also suggested bouncing it off the guys here for ideas.

As for the idea of using attenuation plugs, I'm having trouble getting my head around that. By attenuating the signal between the source and preamp, wouldn't that just preserve the gap between the top and bottom? If I could somehow insert them between the preamp and power amp sections of the Hegel, that would make sense to me. But doing it this way just seems like I'll be attenuating the entire signal — including the bass — only for the purpose of being able to turn it up more? Meanwhile, the exact same thing is happening to the signal heading for the Omegas.

Maybe this helps. I pulled up the owners manual for the Crown amp Louis suggested, and it shows an option to increase the input sensitivity (to 0.775V) for sources with inherently low output.



Thanks!
Dane