It's stupid question time...even without a subwoofer output, can my tube amp/preamp support a subwoofer?

[jt1stcav]

Several years ago I built a DIY subwoofer utilizing a 15" Dayton Audio DVC Series driver inside a 3 cubic foot sealed enclosure powered by a Carver M-400t power amp bridged to mono for 500 watts, using an AudioControl Richter Scale Series II active crossover for my audio system (see my profile and click on the top link). It blended well with my Cornwalls, with bass frequencies from 90Hz on down going to the sub (which I figured went down to 18Hz tops).

When I was later laid off and forced to liquidate my assets, everything but my Cornwalls was eventually sold...since then, I've built up my audio system again but in a much more simplified form, using a 300B SET stereo amp, a 6SN7 SRPP linestage preamp, a CD player and cassette deck, and my Cornwalls. These classic Heritage loudspeakers only go down to 38Hz, which in itself isn't bad, but I listen to alot of pipe organ music that's rich in extreme low bass content well below 25Hz, and I miss not having a subwoofer connected to my system that's capable of reproducing these low frequencies.

My concern is this...

If I had an AV receiver/preamp/processor with a dedicated sub output, connecting a subwoofer like those from Sunfire, Definitive Technology, and Earthquake would be a simple affair by using a single interconnect. Unfortunantly, my tube amp and preamp don't have a second output for a sub, so I just assumed that I was out of luck and not able to add a sub to my simple audio system.

I recently looked at a Sunfire subwoofer on eBay and it has a stereo pair of input and output jacks, so I was wondering if I could actually add a sub like this one to my tube system. Is it possible to:

1) Connect my stereo amp straight to this type of subwoofer's left and right outputs, and connect my tube preamp's output to the sub's left and right inputs?

2) Would this become an active or passive connection to the sub's crossover controls?

3) Would my Cornwalls play at full range, or would the sub's crossover take over the Cornwall's bass output at a certain frequency?

4) Would I have to use a "Y" connector for summed mono output?

5) Or would I have to use the sub's speaker level inputs, utilizing another pair of speaker cables?

6) Is any of this even possible with my simplified system, or am I simply out of luck, inwhich case I'll have to continue using the Cornwalls by themselves and miss out on the lowest bass frequencies while listening to pipe organ recordings?

Any or all answers to these questions would be greatly appreciated! Thanks in advance.

[meuge]

I have reviewed a wonderful piece of equipment earlier, the Outlaw ICBM-1 here:

http://forums.klipsch.com/idealbb/view.asp?topicID=56794

It's an analog in-line external crossover, which is a great $250 (or $200 for B-stock) way to add a subwoofer to a 2-channel system. Check out my review for an in-depth look at the device.

I would not recommend using high-level inputs/outputs. It takes detail, soundstage and life out of the system, in my experience.

You can split the signal using a Y-adapter and adjust the sub's crossover in order to make a seamless transition, but I am not sure if that's as reliable as using an actual crossover.

[formica]

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On 1/20/2005 12:21:11 AM jt1stcav wrote:

Is it possible to:

1) Connect my stereo amp straight to this type of subwoofer's left and right outputs, and connect my tube preamp's output to the sub's left and right inputs?

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Yes

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2) Would this become an active or passive connection to the sub's crossover controls?

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Varies according to the subwoofer (ie: it's amp) but it will usually be an active type... and it will split the line level signal into high and low frequencies.

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3) Would my Cornwalls play at full range, or would the sub's crossover take over the Cornwall's bass output at a certain frequency?

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If hooked up as you mentioned in (1) and if (2) is "typical" the sub would take over from the Cornwalls below the crossover frequency. It is useful when using Tube amps as it'll reduce their power requirements... and you'll end up with a greater dynamic range.

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4) Would I have to use a "Y" connector for summed mono output?

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From what you described in (1), it has stereo line level input so this would be a mute point?

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5) Or would I have to use the sub's speaker level inputs, utilizing another pair of speaker cables?

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Again... From what you described in (1), it has stereo line level input so this would be a mute point?

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6) Is any of this even possible with my simplified system, or am I simply out of luck, inwhich case I'll have to continue using the Cornwalls by themselves and miss out on the lowest bass frequencies while listening to pipe organ recordings?

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You can always find a matching sub to fill in your Cornwalls bottom end.

Good luck...

Rob

[DrWho]

You can also use a few Y-adapters to split the signal before your amp and then plug them into the stereo line level inputs on your sub. You might be able to get away with another Y-adapter if your sub only has one input, but this might introduce crosstalk and other impedance related issues. A better approach would be to use a stereo to mono adapter that uses transformers to keep the signals isolated.

[dodger]

The truly stupid question is the one not asked.

dodger

[Colin]

I love stupid questions! They are so easy.

Yes. Do it. Corns need a powerful sub.

[jt1stcav]

Thanks everyone for your generous answers to my many questions. I didn't realize I could use a powered sub with my simple tube gear (thought I needed the proper outputs). As long as I purchase a sub with the proper stereo inputs and outputs, it looks like my Cornwalls may be treated to some low octave bass in the near future!

[mike stehr]

You know I have a little 5-watt Single-ended Magnavox 6BQ5 console amp.

It has sufficent bass itself with the Cornwalls of mine. But you like organ music, and I like weird stuff with lots of bottom end.

If you have a nice powerful PP amplifier with lots of wattage on the bottom end, then a subwoofer may or may not be needed, depending on preference.

I still have and use my SVS 16/46's, one parked next to each Cornwall. Depending on the amplifier used and types of music, I either use them, or just leave them off.

The DVD unit I'm using has a analog subwoofer line out, or you can use a splitter from the source.

I bought a Audio Control PCA thingie at a pawn shop, it has a 3-way active crossover.

I run a 40 Hz single to a rather wore out bridged NAD amplifier. The subs are wired in series.

You could try splitting the line out at your pre-amp, but I dunno if there may be impedance matching issues, one would just have to try it.

You could use the pre-amp VC to control the bass level with the rest of the single level, once the gain is set on the sub amp.

I need to start looking for some sort of replacement amp/amps for the SVS's.

The SVS help for watching movies, they help with techno, thrash, dark ambient, or just ambient stuff. Anything with the low bass beats, you won't hear these frequencies with a flea amp. Kinda, but just little poofs and oomphs...

My little re-cased SI digi-amp lashes up real nice with the SVS. The sand-flea amp.

Though the SI amp has better SS-like bass sonics than the low watt tube amps.

[mike stehr]

I gotta quit hitting "back" when I already "submitted".

[jt1stcav]

I hear ya, Mike. The Cornwalls do a decent job with jazz, blues, classical, and some rock. But then with industrial, gothic, technodance mixes, and naturally organ, a sub can really come in handy.

I'm not really interested in DIY setups like I was years ago, and I don't care to go back to rigging up a make-shift system for myself like I had before. Don't get me wrong, I'm not in no way, shape, or form knocking what you're doing with your NAD and SVS rig (I know my previous DIY Carver/Dayton/AudioControl setup thumped like you wouldn't believe)! Guess I've gotten lazy in my old age; I just want a plug 'n' play subwoofer that has all the input/outputs that will connect to my SET amp and linestage pre, and not have to go through obtaining additional amps and processors like I had before. Now that I know I can connect the proper sub to a system like mine (without subwoofer outputs), that's what I'm going to look for.

I'm tired of the lil' poofs and oomphs...

[mike stehr]

I can agree with you there. A self-powered subwoofer makes life way more easy.

I gotta deal with a real tired NAD amp, and active crossover that is almost fried.

I really, really need to find a couple of plate amps that will push the SVS 16/46 to at least respectable levels at a realistic price. a internal built-in x-over would be nice.

[jt1stcav]

Would any of these sub plate amps from PartsExpress.com work for you?

http://www.partsexpress.com/webpage.cfm?webpage_id=3&SO=2&&DID=7&CATID=43&ObjectGroup_ID=505

[formica]

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On 1/20/2005 9:08:14 PM mike stehr wrote:

I gotta quit hitting "back" when I already "submitted".

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You would think that you'd have it down-packed after 3000posts...

You could also take a look at some of the Rythmik Audio plate amps which have a good reputation. Personally I prefer a regular amp in the equipment rack... like you are running now, but perhaps a better x-over like the Paradigm X-30 or the Outlaw ICBM.

But that is just me...

Rob

[mike stehr]

"You could also take a look at some of the Rythmik Audio plate amps which have a good reputation. Personally I prefer a regular amp in the equipment rack... like you are running now, but perhaps a better x-over like the Paradigm X-30 or the Outlaw ICBM.

But that is just me..."

Rob

Yeah, I would prefer a regular looking amp. I just mentioned plate amps because they are a little cheaper.

All I want is just a simple active low-pass crossover with a gain pot and a way to adjust center frequency using resistors instead of a variable pot.

The Active crossover I use now use resistors to adjust center frequency. You can dial it in to any frequency you want. I may have blew a op-amp, or a bad coupling cap....

Maybe I'll lurk eBay when I'm more flush.

I have a kit to build a breadboard active crossover, and a service manual for the amp. That may be the cheapest fix.

[jt1stcav]

Ah, yes...reminds me of years past when I had my Carver M-400t cube strapped into 500 watts mono, fed through the classic AudioControl Richter Scale active crossover/bass EQ for my DIY 15" sub. I'm quite confident it went well below 20Hz...on certain organ passages with a full-blown 32' pedal note playing low D, you could actually "feel" the air moving about the room from the sealed sub enclosure! Goosebump central, baby!