SWR Bass 350 Red Face

[MichelD]

There is a SWR Red Face Bass 35O for sale here locally for a stupid cheap price.

I see a few reviews but not a lot on this site.

Some say the fan is very noisy, that they can overheat and that they are more mid-rangey than "bassy."

Do people like them?

Are they heavy? I see it has a tube preamp.

 

[agedhorse]

Beware that some parts are no longer available. Haven’t been for some time.

 

[MichelD]

Beware that some parts are no longer available. Haven’t been for some time.

Thank you.

 

[Jeff Scott]

I had one back on the late '90s that I ran a pair of Bag End S15D cabs with. I found the amp's frequency balance to be tilted in favor of the high end with less bottom end, but that could possible also be due to the BE cabs which didn't have any real bottom end to them, IME. As they were the only cabs I had at the same time I had the Bass 350 I have no idea which was the real culprit in this frequency imbalance, so take that with a whole mine full of salt, say, the one under Lake Erie.

I don't recall the fan being noisy, but the amp did run rather hot which concerned me a bit.

 

[Smokey P]

Reviving this thread. Any difference between the red face bass 350 and the chrome bass 350? Thanks

 

[Count Bassie]

I had one back on the late '90s that I ran a pair of Bag End S15D cabs with. I found the amp's frequency balance to be tilted in favor of the high end with less bottom end, but that could possible also be due to the BE cabs which didn't have any real bottom end to them, IME. As they were the only cabs I had at the same time I had the Bass 350 I have no idea which was the real culprit in this frequency imbalance, so take that with a whole mine full of salt, say, the one under Lake Erie.

View attachment 4454493

I don't recall the fan being noisy, but the amp did run rather hot which concerned me a bit.

The amp is designed to run hot because the chassis is aluminum- the whole thing is a heat sink. That is, believe it or not, the cooling system. Hot=Happy.
I think the Bag End cabs was your problem with the lack of low end. That said, I've got an Eden WT405 that brings a sweet, clean, very low-end bloom that the SWR doesn't really deliver. Still, my Bass 350 into a Big Ben or Goliath-II is pretty darned satisfying.

 

[agedhorse]

The amp is designed to run hot because the chassis is aluminum- the whole thing is a heat sink. That is, believe it or not, the cooling system. Hot=Happy.
I think the Bag End cabs was your problem with the lack of low end. That said, I've got an Eden WT405 that brings a sweet, clean, very low-end bloom that the SWR doesn't really deliver. Still, my Bass 350 into a Big Ben or Goliath-II is pretty darned satisfying.

That’s not really true, the chassis is not used as a heat sink and there is no direct thermal connection between the heat sinks in the amp and the chassis. It’s an urban myth.

 

[Count Bassie]

That’s not really true, the chassis is not used as a heat sink and there is no direct thermal connection between the heat sinks in the amp and the chassis. It’s an urban myth.

I have understood that the reason the chassis is aluminum is to dissipate heat. So this is a flaw? But all of the SWR stuff was built this way, right?

 

[Count Bassie]

That’s not really true, the chassis is not used as a heat sink and there is no direct thermal connection between the heat sinks in the amp and the chassis. It’s an urban myth.

From the manual:
"Most musical instrument amplifiers on the market today use steel for their chassis, which does not conduct heat as well as aluminum. The 350x uses an all aluminum chassis and front panel because it has less impurities than steel, is less susceptible to rust, and is a better conductor of heat. This results in the chassis acting as an additional heatsink, drawing heat away from heat-producing components inside and thus extending their life. In this manner, we feel we have produced a more reliable amplifier, but at the same time, the outside of the 350x will get warmer than cases made out of steel."
I dunno, it may be a novel way of doing a thing, but it seems that it's a simple and common sense method of keeping things cool. I've never had one go belly up, and they get hot.

 

[agedhorse]

IMO, this was a marketing statement, reinforced by Fender’s need to redesign the power amps and cooling systems to reduce failures and comply with modern safety regulations.

 

[Count Bassie]

IMO, this was a marketing statement, reinforced by Fender’s need to redesign the power amps and cooling systems to reduce failures and comply with modern safety regulations.

The same read was in the pre-Fender model's manual.
All I got is what the manufacturer says, and they were very successful.

 

[Jeff Scott]

Note the heatsink and the fan at the end of it. The case top has slots at the other end (not shown as the case top is removed, here) for the heat to exhaust out the amp.

The aluminum case is there (most likely) to reduce the weight of the amp.

 

[Count Bassie]

Note the heatsink and the fan at the end of it. The case top has slots at the other end (not shown as the case top is removed, here) for the heat to exhaust out the amp.

View attachment 4557345

The aluminum case is there (most likely) to reduce the weight of the amp.

Fair enough. The fact that the whole chassis gets hot though means that it's dissipating heat. For whatever reason this situation exists, it is contributing to cooling.
I can't go any further, to me it's not an issue if the amp functions without issue- meaning no noticeable issue.

I am not actually knowledgeable about this kind of thing...

 

[Jeff Scott]

Of course the case will get hot and help in dissipating the heat. IMO+E, given the SWR amps I have owned and others I have used, too, the main issue I believe is that the amps just do not have adequate cooling capability, to begin with.

 

[agedhorse]

Of course the case will get hot and help in dissipating the heat. IMO+E, given the SWR amps I have owned and others I have used, too, the main issue I believe is that the amps just do not have adequate cooling capability, to begin with.

This is more true in the older models, the newer Fender revised models addressed much of this.

 

[Jeff Scott]

All of my experience is with pre-Fender models.

 

[Al Kraft]

This is more true in the older models, the newer Fender revised models addressed much of this.

This matches my user experience as well. SWR actually started to address this during their pre-Fender years by adding a cooling fan to some models. Below is a cut and paste from the SM-400 owner's manual and explains why those "SWR's were designed to run hot" thoughts about the early SWR heads are out there. IMO the chassis/case material discussion was accurate in terms of the difference in heat transfer coefficients between steel and aluminum. However, to the best of my knowledge that wasn't actually enough to deal with heat at the sources where the heatsinks really needed some active air movement to get the convective heat transfer to where it needed to be.

CONCERNING CHASSIS HEAT One of the most asked questions about our amplifiers is why they tend to get warmer than other amps. The chassis of your amplifier can get quite warm during normal usage. This is especially true if you are using a 4 ohm total impedance in the Bridged mode. This is because a 4 ohm impedance (or 2 ohms per channel in the Stereo mode) introduces the least efficient condition of the unit (ie: power drawn from the outlet in relation to power produced in the speakers). The difference in these two figures can be as high as 300 Watts. This would be the equivalent of putting a 300 Watt light bulb inside a metal box which would obviously get quite hot. Most musical instrument amplifiers on the market today use steel for their chassis which, in most cases, is considerably cheaper than aluminum and does not conduct heat as well as aluminum. SWR uses all aluminum chassis because they have less impurities than steel, are less susceptible to rust and it is a better conductor of heat. This results in the chassis acting as a heatsink drawing heat away from heat producing components inside and thus extending their life. In this manner, we feel we have produced a more reliable amplifier, but, at the same time, the outside of our units will get warmer than cases made out of steel. The only condition you should be aware of is if one or more of the power amplifiers in your unit becomes "over biased." This condition can be recognized by turning your amplifier on and letting it sit without speakers plugged in and without playing it. If, under these conditions, your unit becomes quite warm, it may be over biased. This situation should be attended to and can be easily remedied in about 15 minutes by a service tech. A power amp can become over biased through continuous vibration or by any large jolt received in shipping, etc. NOTE: UNITS MANUFACTURED AFTER SEPTEMBER, 1993 AND HAVING A SERIAL NUMBER GREATER THAN #6125 HAVE AN INTERNAL COOLING FAN.

 

[slagheap]

some time ago i used a red faced one ( the model with a fan defeat switch, ) as a back up amp. never any problems, but it only came out of the trunk of the car a few times...

 

[avi]

This is more true in the older models, the newer Fender revised models addressed much of this.

So do you feel that the Fender era ones are a safer bet used? As far as parts available and heat dissipation, etc. I think I trust your opinion the most on amps. You have designed some of my favorites.

 

[agedhorse]

So do you feel that the Fender era ones are a safer bet used? As far as parts available and heat dissipation, etc. I think I trust your opinion the most on amps. You have designed some of my favorites.

Yes, the designs are better and the thermal management is better, but there are still the significant issue of some part no longer being available. Fender has no parts or support for SWR.