Speaker drivers for 2 Watt and low watt amplifier

[BasicHIFI]

Experimentation with the primarily Radio Shack 40-1011 and a locally purchased tweeter has shown me, surprisingly that a low powered amplifier just might be all I need for a small room. This article is encouraging: So far I have used the output from powered computer speakers, a Sony CD-6 portable CD/Casette to connect to the 40-1011 speakers in parallel with a tweeter and they sound fairly pleasing. The resistance on the speakers using the multimeter was found to be 8-11 ohms. The question is will I burn out my speakers using a low power amplifier.This post advises not to increase the volume to the point you hear distortion. Is there a better way, for example to use a multimeter to measure output voltage (AC or DC setting) to make sure I do not burn out the speakers due to clipping of the amplifier? Where can I get speaker drivers rated at 2 Watts minimum, are they required anyway?

 

[davedotco]

The use of low powered amplifiers go hand in hand with high sensitivity speakers, frankly the higher the better.

Sadly good quality sensitive drive units are pretty expensive, many vintage drive units have the required sensitivity but unless you know what you are doing, it is very hit and miss.

Take a look at suppliers like Wilmslow Audio and Falcon, see if you can find anything with a sensitivity in the mid to high 90s (dB/m/w) that is within budget.

 

[lindsayt]

Depends what you call pretty expensive...

http://www.ebay.com/itm/One-Pair-2Pcs-ALTEC-drivers-806-8A-H-811B-GOLD-Horn-Voice-Of-The-Theater-/272057690806?hash=item3f57e6eab6:g:tJUAAOSwHjNWCXPS

http://www.ebay.de/itm/Ein-paar-Electro-Voice-EVM-1824-M-und-8HD-/141840608007?hash=item21065beb07:g:J4wAAOSw8-tWW1nn

http://www.ebay.com/itm/JBL-2445J-Compression-Drivers-Horn-pair-from-original-JBL-speaker-subwoofer-/221841709680?hash=item33a6cbda70:g:8qEAAOSwd0BVvMip

http://www.ebay.com/itm/Vintage-Pair-of-Frazier-Mid-High-Drivers-and-Wooden-Horns-Drivers-16-Ohms-/381468847071?hash=item58d150abdf:g:mHIAAOSwd4tT-5-b

 

[davedotco]

I am quite sure that we both know our way around the kit listed but unless you know your 1823 or 1824 from your 1824m, and are sure which bass drivers can be refurbished and which can not, this can be a minefield for the ordinary hi-fi enthusiast.

In any case, £200 and up for a pair of HF units are perhaps a little pricy for someone shopping at radioshack, though I must admit the Altec units look tasty. Know anyone with a decent magnetiser?

 

[BasicHIFI]

The use of low powered amplifiers go hand in hand with high sensitivity speakers, frankly the higher the better.

Sadly good quality sensitive drive units are pretty expensive, many vintage drive units have the required sensitivity but unless you know what you are doing, it is very hit and miss.

Take a look at suppliers like Wilmslow Audio and Falcon, see if you can find anything with a sensitivity in the mid to high 90s (dB/m/w) that is within budget.

The listed Radio Shack speakers are listed with a sensitivity of 92, which is good. I want to firstly make sure that there is a way to prevent burning out the speakers due to clipping of the amplifier. Of course I can use a low powered amplifier, but how do I know at what volume the speakers will get damaged? What about an electronic speaker cut off for the speaker itself or is this overkill?

Wimslow Audio has some reasonable units, thanks.

While I am at it, some low cost amps are recommended on this site.

 

[lindsayt]

Simplest way is to buy or borrow a calibrated sound meter. Measure the sound at 1 metre directly in front of the speaker, paying attention to the peak values. If it's over 90 dbs (with 92 db efficient speakers give or take a bit depending on their impedance) you're in danger of clipping with a 2 watt amp.

You'll probably find that 90 dbs at 1 meter from your speaker is a lot louder at your listening position than you normally listen at - depending on your room size, your ears, your tastes.

The website you linked to gave good advice - especially for the American market where Dynaco ST 70's are more plentiful than in the UK. They do mention the NAD 3020, which along with the Creek CAS4040 (which I prefer to the NAD) and the A&R A60 (which I prefer to the Creek) offer good sound for almost no money. I also like classic, old, high end pro amps that can be bought really cheaply and can sound really good (better than the A60).

Something like a T amp is great if you want something that sounds acceptable and can fit in your pocket. For sound quality I would take an A&R A60 over every T amp I've heard so far.

If that website were to give advice on good cheap speakers / speaker drive units I'd expect it to be in a similar vein - ie don't buy new; buy used. Buy a tried and tested classic that can be bought for little money.

 

[friendly_ghost]

In your link the author claims the following:

I recently bought a 31-year-old NAD 3020 integrated amplifieron eBay for $66. It was rated at just 20 watts per channel into 8 ohms, but it can deliver as much as 58 watts into 4 ohms, and 72 watts into 2-ohm speakers!

How is that even remotely possible? How can a speaker output 290% of the power when the impedance halves?

 

[davedotco]

In your link the author claims the following:

I recently bought a 31-year-old NAD 3020 integrated amplifieron eBay for $66. It was rated at just 20 watts per channel into 8 ohms, but it can deliver as much as 58 watts into 4 ohms, and 72 watts into 2-ohm speakers!

How is that even remotely possible? How can a speaker output 290% of the power when the impedance halves?

Either they are quoting instantaneous peak power into lower impedances, perfectly reasonable in my view, or they are just making it up.

Note. Some manufacturers deliberately downrate their amplifiers into 8 ohms so that the can say they double their power into 4 ohms, seen as a mark of a good amplifier in some quarters.

 

[chebby]

In your link the author claims the following:

I recently bought a 31-year-old NAD 3020 integrated amplifieron eBay for $66. It was rated at just 20 watts per channel into 8 ohms, but it can deliver as much as 58 watts into 4 ohms, and 72 watts into 2-ohm speakers!

How is that even remotely possible? How can a speaker output 290% of the power when the impedance halves?

Having been an owner of a NAD 3020 amplifier (when I was in my late teens) I can vouch that it must have been capable of a lot more than 20 watts per channel. Even through a little pair of AR18s it sounded vast. I used that combination for a few parties and it sailed through (with an Akai 4000D open reel usually). I didn't even need the 'soft-clipping'.

I've no doubt the sound was coloured - didn't know about such things back then - but hey! It sounded excellent. I'd still like to hear a well-serviced 3020 and AR18s system even now. Although maybe not. Maybe it would sound #### and i'd be disillusioned.

 

[plastic penguin]

The use of low powered amplifiers go hand in hand with high sensitivity speakers, frankly the higher the better.

Sadly good quality sensitive drive units are pretty expensive, many vintage drive units have the required sensitivity but unless you know what you are doing, it is very hit and miss.

Take a look at suppliers like Wilmslow Audio and Falcon, see if you can find anything with a sensitivity in the mid to high 90s (dB/m/w) that is within budget.

I know my old Wharfedale E20 have a sensitivity rating of 96db, but minimum amp power IIRC is 5-40 watts.

 

[DocG]

In your link the author claims the following:

I recently bought a 31-year-old NAD 3020 integrated amplifieron eBay for $66. It was rated at just 20 watts per channel into 8 ohms, but it can deliver as much as 58 watts into 4 ohms, and 72 watts into 2-ohm speakers!

How is that even remotely possible? How can a speaker output 290% of the power when the impedance halves?

Either they are quoting instantaneous peak power into lower impedances, perfectly reasonable in my view, or they are just making it up.

It's probably the former. NAD often quote "Continuous Output Power into 8 and 4 Ohm" and "IHF Dynamic Power into 8, 4 and 2 Ohm". Which IMO is useful info for use in the real world.

 

[BasicHIFI]

I have a few of these on my phone. Seems accurate for the quiet room I am in. Maybe these could take the place of a sound meter?

DiGi+Analyser

JBL Tools

1 watt at 1 metre means a 2 watt per channel amp is close to clipping or does that apply to 1 watt per channel amps?

 

[Vladimir]

Zilch's Econowave design comes to mind.

Eminence Beta-10CX (2" voice coil) 95dB/2.8V/m + Selenium D220ti + Pyle PH612.

 

[Vladimir]

In your link the author claims the following:

I recently bought a 31-year-old NAD 3020 integrated amplifieron eBay for $66. It was rated at just 20 watts per channel into 8 ohms, but it can deliver as much as 58 watts into 4 ohms, and 72 watts into 2-ohm speakers!

How is that even remotely possible? How can a speaker output 290% of the power when the impedance halves?

Having been an owner of a NAD 3020 amplifier (when I was in my late teens) I can vouch that it must have been capable of a lot more than 20 watts per channel. Even through a little pair of AR18s it sounded vast. I used that combination for a few parties and it sailed through (with an Akai 4000D open reel usually). I didn't even need the 'soft-clipping'.

I've no doubt the sound was coloured - didn't know about such things back then - but hey! It sounded excellent. I'd still like to hear a well-serviced 3020 and AR18s system even now. Although maybe not. Maybe it would sound #### and i'd be disillusioned.

20W in 8 ohms continuous is plenty to get loud, but every larger transient peak will be trimmed. Maybe this would explain its dark and a bit muddy character.

 

[BasicHIFI]

This SPL calculator seems to indicate that with ordinary 86 " dB SPL (1 W/1 M)" sensitivity speakers, I can get 77.2 "dB SPL at listening postion[/b]" of 9 feet with only 0.5 watt. If this is correct, then I have found the specs for my minimum system.

This leaves me with a wider range of speakers to choose from, since many speakers are at least of sensitivity 86.

I am in the process of putting together my own low watt chip amp. I have already done some testing with a chip amp and the Radio Shack 40-1011 let's say I am impressed.*smile*

Quote from Paul Klipsch interview:

"Bragging about input power is a little like bragging about how much gasoline your car can bum."

"...distortion (to a first approximation) is proportional to power input in any loudspeaker. It follows that distortion is inversely proportional to efficiency. Horn speakers are inherently more efficient"

 

[Boomer]

http://www.blumensteinaudio.com/all-products/

I've got a set of orca minis and a set of tritons on the way. Excellent, very sensitive drive units and they sell individual drivers.

My Tritons are 92db sensitivity.

 

[BasicHIFI]

Those are some good looking speakers. Having listened to a single/midrange woofer I can see dimly as if through a veil, the value of having one speaker cover all the important frequencies, especially for vocals and acoustic intruments.

They sell individual drivers for $30 which is an incredible steal. Any questions about real low end bass was answered by this review, suggesting using a subwoofer for completeness. In fact, some full ranges use a tweeter as well (heresy?). All they need is a wall-mounted version - but maybe I could use their drivers to build one.

From the review : "Not only did the soundstage explode in all three directions, these little speakers distinctively revealed the differences in amplification handily. Pretty damn impressive for a $500 pair of speakers."

 

[Boomer]

They are so right, I have the orca minis which are now discontinued for there new model, but I promise anyone they are absolutely brilliant. They are so satisfying, you need to hear to believe and my door is always open if anyone wishes to audition them.

 

[BasicHIFI]

Interesting "Boomer", but that *dash1* is there no way in this day and age for you to communicate how it sounds- maybe a video, maybe a close miked recording, or maybe a screenshot from a spectrum analyser? Play a piece of music through normal speakers and then the full range ones, record both and send the file over?

 

[Boomer]

OK, ile do my best. Im away at the moment but when I get back and when have 5 mins I will post a you tube video. I'm waiting for my Tritons to turn up so I will video them aswell, but they may take a while.

By the way there are videos and reviews online of the Blumenstien kit.

 

[BasicHIFI]

Does this You Tube video of the Blumenstien sound like the real thing? Very clear sound, though.