How to know wattage of unlabeled speakers?

Madeline12

Madeline12

Super Member
Got some Scott S-11’s the other day. Sound great, but there’s no indication of the wattage. Also, I understand it’s adjustable ohms of 6-8. I noticed they’re a bit quieter than the other two sets of speakers I own. Is this possibly because of the wattage capacity? Also, how do I adjust the ohms? I don’t see anything that will let me control that. I have a pic of the back. I’ll try and get better close up photos when I’m back home from work. The only switch I see is an adjustment for high frequency levels. Can’t seem to find anything online.

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I don't think that their impedance is adjustable. It says 6-8 ohms because that is the range at which they operate within across most frequencies. Impedance varies by frequency, so they may drop well below and above 6-8 ohms at certain frequencies.

Based on their era, I would guess that they have fairly low power handling capabilities, but this is not particularly important. You can use them with an amplifier capable of putting out more power than they are capable of handling. Simply use the volume control to limit the power. If the speakers start sounding strained or harsh, make a popping noise, or otherwise sounding different than they do at moderate volumes (other than louder, of course), turn down the amplifier.
 
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spark1 said:
Their impedance is not adjustable. It says 6-8 ohms because that is the range at which they operate within across most frequencies. Impedance varies by frequency, so they may drop well below and above 6-8 ohms at certain frequencies.

Based on their era, I would guess that they have fairly low power handling capabilities, but this is not particularly important. You can use them with an amplifier capable of putting out more power than they are capable of handling. Simply use the volume control to limit the power. If the speakers start sounding strained, make a popping noise, or otherwise sounding different than they do at moderate volumes (other than louder, of course), turn down the amplifier.
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I've worked on a few pairs of Scott speakers from that series. If I remember correctly, they used Temple capacitors...not known for their quality. Every such cap I've ever removed from a crossover was significantly out of spec...so if you plan on keeping these speakers, replacing the crossover caps would almost assuredly improve their sound quality.
 
spark1 said:
I've worked on a few pairs of Scott speakers from that series. If I remember correctly, they used Temple capacitors...not known for their quality. Every such cap I've ever removed from a crossover was significantly out of spec...so if you plan on keeping these speakers, replacing the crossover caps would almost assuredly improve their sound quality.
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Great info! Do they have high voltage? I hope to learn how to replace capacitors, but I’d rather start out small. I know how to solder. I’m just curious if the quietness could be attributed to these capacitors, as it’s noticeable but not extreme.
 
The output of the midrange and tweeter could certainly be reduced if the caps are significantly out of spec. They often drift higher in capacitance with age, raising their crossover points. Also, ESR (resistance) often goes up with age...resulting in lower output.

Also, it is likely that the sensitivity of these speakers is fairly low...probably around 86dB or so. The lower the sensitivity, the more power they need to achieve a given loudness. Nothing you can do about this. EDIT: So what this means is that to achieve the same loudness as a pair of speakers with a higher sensitivity rating, the volume control would have to be turned up higher.

One of the challenges with speakers of this ilk are that you are somewhat boxed in by relatively low sensitivity and relatively low power handling. They need quite a bit of power to get loud, but can't handle high power levels very well.

No worries about getting zapped with capacitors like the ones you will find in these speakers.

Pretty easy to change them. While folks like to experiment with various higher-end caps in better speakers, I would recommend just going with Dayton polypropylene caps (Parts Express). The 5% tolerance will be just fine for those old Scotts. Note that they will be larger, so you may need to place them differently than the current caps. If so, you can just solder in some jumper wires if needed to reach from the new caps to their connection points.

Note that you may not be able to find the specific values Scott used. You can wire caps in parallel to add up to the needed value. For example, if you need a 5uf capacitor, you can use a 4uf and a 1uf, in parallel (NOT series).
 
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The difference in loudness between your different speakers comes down to their efficiency, which is rated in decibels. A 90dB rated speaker will sound twice as loud as a 87dB rated speaker at the same position of the volume control.
 
http://www.hhscott.com/speakers.htm

Looks like your speakers are rated to 60w/channel.

Re changing capacitors, I cut off the leads right at the ends of old cap. Using a needle-nosed pliers make a loop at the ends of the old leads. Tie the new cap in place and solder. If the original leads and new cap leads combined are long enough, you should be able to solder in free space. As noted the new caps might be larger so don't solder and clip the unused ends until your sure you have clearance or enough room to secure(if necessary) them to the insides of the speaker. You'll have to do this through the woofer opening since the backs look glued in place. I didn't find a picture of the crossover for these in my searching.

I got back into soldering by doing simple crossovers and still shy away from circuit boards.

Mark
 
The wpc on my receiver is 16W so I will stop using these speakers. I’ll probably switch them out with my sisters, which are less wattage. Don’t want clipping.

Thank you everyone for all the info! I will be sure to listen when I recap!
 
I'm using a 3w/channel amplifier on speakers that are rated to 75w/channel. I've had my 75w/channel receiver playing on speakers rated for 25w/channel. In the second example, I just don't over due it with the volume knob. Much of it is trial and error. If it sounds strained then turn the volume down.
 
I think those are late 60's. Sound better than most of it's type for the time. Not thought of as power hungry. A very easy to drive impedance stable speaker made to run with the Scott receivers of the day. Most of which were a modest 20 to 30 watts. Some as few as 15. The three caps are most likely Temple and suspect at best. If they are bad the CTS mid will choke. It will sound dull. If it's not clean and lively but the mid is working with 16 watts somethings wrong. The cap board on most similar Scott speakers is easy to remove and work on. The switch cleans up good too.
Good speaker. Don't get fooled by the loud thing on this one.
 
Madeline12 said:
The wpc on my receiver is 16W so I will stop using these speakers. I’ll probably switch them out with my sisters, which are less wattage. Don’t want clipping.

Thank you everyone for all the info! I will be sure to listen when I recap!
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To put it simply, clipping does not depend on the speaker power rating. Clipping is a result of overdriving the power supply in your power source.
 
F1nut said:
To put it simply, clipping does not depend on the speaker power rating. Clipping is a result of overdriving the power supply in your power source.
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Unfortunately because of the lower volumes of the speakers I end up pushing more power out of my receiver by turning the volume up, if I’m thinking correctly. So...not sure I guess. But you are probably right.
 
What F1nut said! Don't worry so much about what the speakers are rated for watt's wise. The manufacturer was not saying you NEED 60 watts to drive them. They were saying pushing above *might* cook something. People use low watt output receivers with speakers capable of handling lots of watts all the time. Many also use high watt amps with speakers built at a time when 15 wpc was the norm. (albeit, with some sanity regarding the volume knob.)
 
cubby01 said:
What F1nut said! Don't worry so much about what the speakers are rated for watt's wise. The manufacturer was not saying you NEED 60 watts to drive them. They were saying pushing above *might* cook something. People use low watt output receivers with speakers capable of handling lots of watts all the time. Many also use high watt amps with speakers built at a time when 15 wpc was the norm. (albeit, with some sanity regarding the volume knob.)
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Gotcha, alrighty! Looks like I’m good then :) I’ll post updates on replacing the capacitors once I get to it. Possibly in a different thread. May need some hand-holding through it but I’m gonna try!
 
Madeline12 said:
Unfortunately because of the lower volumes of the speakers I end up pushing more power out of my receiver by turning the volume up, if I’m thinking correctly. So...not sure I guess. But you are probably right.
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The perceived loudness at any point along the volume knob rotation It would depend on the sensitivity of the speakers, not the wattage rating. What receiver are you using and what are the other two sets of speakers you compared them to.
 
cubby01 said:
The perceived loudness at any point along the volume knob rotation It would depend on the sensitivity of the speakers, not the wattage rating. What receiver are you using and what are the other two sets of speakers you compared them to.
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My receiver is a Kenwood KR-2400.
The other two speakers are Lafayette Sk-300’s and University Sound Ultra 1’s.
 
The new
cubby01 said:
The perceived loudness at any point along the volume knob rotation It would depend on the sensitivity of the speakers, not the wattage rating. What receiver are you using and what are the other two sets of speakers you compared them to.
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Deja vu all over again.
 
Welp, just took out the woofer of the Scott’s, and there’s tons of insulation in these things. Is it likely I’ll have to take it all out in order to change the capacitors? What a pain...

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