Super Reverb voltage questions

[Leo_Gnardo]

Ok the amp shows fine on the scope. But here is another question. Will tired speakers not sound as loud as they once did? The only other cab I have to test with is a 15in 16ohm speaker. It just really should sound louder they are the original speakers in it and it looks road worn for sure. How can you tell if a speaker is tired or worn out?

Sometimes speaker magnets lose some strength over time, and the sound can become weak & flabby. Comparison with a similar new speaker is the only way I can suggest. Another thing, are you sure ALL your speakers are working? I had a customer come in with his Super Reverb, complaining it sounded weak and broke up badly at low volume. Surprise, only one speaker was working. Sure you can test the amp with your 16 ohm speaker but understand there will be a substantial derating of power with that bad an impedance mismatch, and it may not prove much. If you're up to buying some new, I've found the cheapest 10" speakers I can easily find, Jensen MOD 10-35, sound plenty loud and aren't annoyingly bright.

[Richard]

At what distortion level are you measuring output wattage? Practically every instrument amp will yield disappointing results measured at clip or some other low distortion level, when compared to its maker's claims. Manufacturers seldom reveal the distortion factor when boasting about their amp's power level, it's typically anywhere from 5% to 20% and sometimes flat out square wave clipping. Not too many techs have a distortion % meter on the workbench, I sure don't. I could be wrong, but my "rule of thumb" is you can add 12% more power for every 5% of distortion. IOW the same amp could measure 100W or 150W, depending on whether it's just a smidge below clip, or at 20% distortion. If you're getting 60W at clip from a Super Reverb, that's fantastic & don't worry any more. Most I work on clip in the 40 to 50 watt range.

What does 10% distortion sound like?

[SoulFetish]

I think Leo's right. A fair test is an A/B comparison to newer versions of similar or the same speakers. A different speaker especially different speaker which is a different size can have a completely different sound characteristics altogether. Plus the efficiency may vary quite a bit.

[Leo_Gnardo]

What does 10% distortion sound like?

With a continuous tone it's obvious that you're no longer in the clean zone. Funny that our ears have a high tolerance for distortion but by the time you're at the 10% mark, hard to deny it's no longer a clean tone.

Picked up one of those hi fi test CD's awhile back. One set of tracks has some peppy jazz rock, recorded with increasing amounts of distortion on each replay as they work up by factors of ten from 0.01%. Hard to tell anything's amiss even with 1%. At 10%, sounds positively cruddy like a cheap transistor AM radio. Considering hi fi manufacturers have been flogging expensive super low distortion gear for decades, it's surprising to find out how much distortion can be in a signal before it's objectionable.

With an individual instrument, continuous distortion at 10% easily noticeable. Sounds great for electric guitar. But you can have peaks well beyond 10% on note attacks, they pass by so quickly our ears fail to notice (good studio engineers may be able to detect them) and the guitar or bass (or whatever) still sounds plenty clean.

[SoulFetish]

What does 10% distortion sound like?

There's all kinds of distortion. Depends on what kind of distortion you mean. Even if you meant "total harmonic distortion" I'm not sure I could give you a good answer. It could sound like a legion of Heart fans singing The Battle of Evermore at the gates of Valhalla for all I know. Maybe Leo's description is better.

[potatofarmer]

Those old Utah speakers are definitely a weak point. Better speakers or more speakers are the two easiest ways to make more loudness for a given amp. My Twin from the same era came with a pair of speakers that not only had poor sensitivity, they also probably only had a power rating of 50W each. Not nearly enough for a "135 watt" amp. Sure enough when I reconed them the old voice coils had a number of discolored spots where the wire had nearly shorted. I replaced those speakers with a pair of Eminence Swamp Thangs - very high sensitivity speakers - and the loudness increased dramatically. Before you couldn't stand in the same room, now you can't stand in the same county.

The downside with a Super, of course, is you have to replace (up to) 4 speakers.

[nosaj]

Those old Utah speakers are definitely a weak point. Better speakers or more speakers are the two easiest ways to make more loudness for a given amp. My Twin from the same era came with a pair of speakers that not only had poor sensitivity, they also probably only had a power rating of 50W each. Not nearly enough for a "135 watt" amp. Sure enough when I reconed them the old voice coils had a number of discolored spots where the wire had nearly shorted. I replaced those speakers with a pair of Eminence Swamp Thangs - very high sensitivity speakers - and the loudness increased dramatically. Before you couldn't stand in the same room, now you can't stand in the same county.

The downside with a Super, of course, is you have to replace (up to) 4 speakers.

Well I unsoldered each speaker and ran tone through each on individually all worked. But on the last speaker that connected to the jack for the amp, unsoldering it showed that only 2 or 3 strands of wire were still connected. All the ends got cut back to fresh wire and resoldered on. Pity is the kids are in bed now so it'll have to wait till tomorrow after work to see if that helped any.

Thanks,
nosaj

[SoulFetish]

Come on, wake 'em up. What's the worst that could happen

[nosaj]

Come on, wake 'em up. What's the worst that could happen

The doghouse ain't big enough

[Leo_Gnardo]

Come on, wake 'em up. What's the worst that could happen

They'll want to be rock guitarists when they grow up. And you'll have the unfortunate task of letting them know they can do one or the other but not both.

[SoulFetish]

They'll want to be rock guitarists when they grow up. And you'll have the unfortunate task of letting them know they can do one or the other but not both.

Ha!
Ladies and Gentlemen..... LEO_GNARDO!!! {A THUNDEROUS APPLAUSE}

In mid season form. That's what I like to see.

[nosaj]

They'll want to be rock guitarists when they grow up. And you'll have the unfortunate task of letting them know they can do one or the other but not both.

We got lots of volume now!

Thanks,\
nosaj

[Leo_Gnardo]

Ha! Ladies and Gentlemen..... LEO_GNARDO!!! {A THUNDEROUS APPLAUSE}

I'll be here all week, and nosaj's kids, 'til they go to college.

Tip your waiters don't forget, and I recommend the chicken tonight, chef's special, it's rubbery.