General Music Chat

The difference in sound was probably due to a different speaker type in your extension cabinet. A lot of CBS-era Fender amps had to have their transformers replaced! I know my Bandmaster's had been done, along with the power caps (twice because the first time as not done correctly) - all before I got it. Never questioned why, but probably for exactly that reason.

Umm the twin is ear splitting loud at setting four....external speakers? why?

I found this for ya;

Most Fender Twin Reverb amps, including the Blackface reissue, operate only on a 4 ohm load and have no means of selecting any other impedance. Exceptions to this are the last original silverface issues that are rated at 135 watts, and later channel-switching models. Operating both together brings the speaker load to 2.7 ohms which is not a problem at all for the Twin Reverb to handle. If, however, you use only the 8 ohm Marshall cab and unplug the Fender speakers, then the amp could be at risk if you play at loud volume.

Whenever you mismatch a tube amp with a much higher load (speaker) impedance, a higher signal voltage is produced across the primary of the output transformer. One loud popping note on the high E string and you could arc-over the output tube sockets, fry the tubes, or zap the output transformer. This is why you cannot run a tube amp without a speaker connected to it. If you must mismatch the load impedance use a lower than rated one, as you are doing now by connecting both cabinets.

Having said this, and making it very clear that I do not advise anyone to connect a higher than rated impendence to any tube amp, generally there is no problem when operating the amp at 8 ohms if your amp is well designed and in good working condition. Connecting a 16 ohm load to a 4 ohm amp is, of course, more risky.

Having said this, and making it very clear that I do not advise anyone to connect a higher than rated impendence to any tube amp.

I don't know where that came from but it is the exact opposite of what is usually recommended for tube amps. Running a higher speaker impedance will only make the amp work a little harder. Running a LOWER impedance speaker can damage the amp. Running a 4 ohm amp like the Twin Reverb with an 8 ohm speaker load will not hurt a thing. It will work a little harder, may run slightly warmer, but should not cause any electronic failure. Running the same 4 ohm amp with a 2 ohm load has a good chance of frying a transformer or other serious damage. Solid state amps are more forgiving.

If you want to run an extension cabinet with the Twin Reverb, disconnect the internal speaker. If the cabinet is the same 4 ohm load, the speaker jacks are wired parallel, which results in a 2 ohm load if both are plugged in. Plug the extension cabinet into the main output jack, if it has two.

If it sounds quieter with the extension cabinet, at the same 4 ohm load, it's probably because the speakers in that cabinet are less efficient. More efficient speakers are louder at the same power level. If it were me, I would check the impedance of the cabinet with a multimeter to be sure it has the correct impedance. If anyone has ever tinkered with the wiring it might not be the same as labeled. Some speakers also just sound cleaner than others to begin with. Some guitar speakers are designed to break up a little easier, just for rock and roll players. Others, like the older EV speakers, had a reputation for being really clean. Don't know about the newer ones, I haven't kept up with them. Some I've seen listed in catalogs, like Celestion and Emminence, list some as being designed to break up faster and some cleaner, some "tuned" so to speak, for blues etc. I don't have my Sweetwater catalog handy to get a direct quote, connection is crappy right now so I won't do any serious searching...

Number of speakers has little if any impact. I can run my 6 watt Fender Champ through the Kustom 2x12 cabinet, 4 ohm so it's close enough to the right impedance of 3.2, and it makes no difference I can discern in volume or sound, except that the 2x12 cabinet is a fuller sound sound since it's moving a lot more air than one 8 inch speaker. Just for kicks I ran a small transistor radio through the speakers of a 2x12 combo amp once, worked just fine. I kept the Champ plugged into the 2x12 cabinet for at home practice for around a year before I moved back to Texas. Never had any problems with either. It only gets a little more bass, no other difference. I ran it through a 4x12 once at a guitar store, same thing. Number of speakers makes no difference, impedance is the main issue, and if the speakers are less efficient, they will not be quite as loud. More speakers will also produce more bass, they are moving a lot more air.

The common advice is never run a tube amp with no speaker load, which is always a good idea, that said, many newer tube amps are built so that it will not do any damage. I can't remember exactly, but I think it uses a grounded jack that will not allow any output signal unless a jack is plugged in. Make sure that jack is connected to a speaker load. That's why the main jack must be used for the extension cabinet. Otherwise it should shut the signal off.

Some amps have one output jack, so you can use a closed back cabinet if you want instead of the internal open back speakers. Closed back cabinets tend to have a tighter bass response. Some have two, you can use one matched impedance cabinet through the main jack, or a pair that will total the right impedance. The jacks are wired parallel, so if you plug in two 8 ohm cabinets you should end up with a 4 ohm load. Mainly it's for sound, open back combo amps can have a flabby bass if you're not careful with tone settings at loud volumes, closed back cabinets have a tighter bass response, not quite as touchy. I've been using my Super Reverb with the built in 4x10 speakers, no problems but I have to be careful about the bass if I crank it a little, it can get really flabby if I give it too much bass. Keep the bass below about 6 and it does great. At lower volumes, it works fine, bass gives me no problems, I usually run it about 7 with volume on 3 to 4 for low volume gigs. We play some places I could use my 6 watt Fender Champ if it didn't sound like a cheesy 8 inch speaker...

I'm trying to use a Fender Pro Jr but having to use a 10 band EQ, the thing gets almost no bass. And I'm spoiled by the Super Reverb, I've had that and a Peavey MX behind me for 25 years, bass that barks like a 10 foot bulldog. The little Pro Jr just won't do much bass with one 10" speaker. If I try to lug the 2x12 cabinet around it defeats the purpose of switching to a small amp that only weighs 30 lbs...and it's 4 ohm, wouldn't work anyway, the amp is 8 ohm.

I've done things like that before. Fortunately not often.

I have a Cort CL1500 hollowbody, much less feedback problems than most Gibbys I've played. I Can crank the Super Reverb to 10 and play it with almost no feedback at all unless I get too close to the amp and turn toward it. If I want feedback I can punch up the Marshall overdrive (Bluesbreaker) pedal and it does great. Still no feedback problems, just there if I want it. I use it all the time with both overdrive and distortion, works perfect.

I had a Rat pedal years ago, sold it because it was too much treble. Great distortion, good volume control and so forth, but too bright. Now I wish I Had kept it, found out years after selling it I could do some modifications and cure that...I'm using my old favorite Ibanez SD 9 distortion now, best distortion pedal I've ever played. If it ever goes south I think I might cry...

I just now noticed Alex LA, I lived there in the 70's, first band I ever played in, first few times onstage (but only one was in Alex other than school jazz band), lost track of everyone I knew long ago though. Haven't been back in 30 years at least.