Express Wattage?

[jckid649]

Does anyone know how many watts the Express is?

[M Fowler]

Considered a 36w amp however, the transformers are spec'd for 50w with 300mA PT, wow!

[Bob S]

Just think of it as a 36 watter that eats 50 watters for breakfast.
Or an amp that drummers love to hate.

[M Fowler]

It's crazy just how loud the Express is compared to my JCM800 50w and Plexi 100w.

The Fenders don't even come close in loudness as the Marshall or Express. But then I'm after good tone and with power.

Mark

[jckid649]

Yeah I'm loving the versatility of this circuit and how at the turn of a knob or adjustment of pick attack you can make it do anything you want!

[jckid649]

Oh and I'm building this as a combo with extension ability. I'm using barn wood that's almost 100 years old for a very different look. A friend is also making a nameplate with my own name for it. I will post picks soon.

[zambo]

Barn wood rules. good call!

[geetarpicker]

Wattage and loudness is somewhat effected by the output transformer used. My originals (and two Pacific tranny clones) aren't all that loud for x2 EL34 amps, and I've compared them side by side to an original 60s Marshall JTM45 and they were very similar in loudness. I've owned some metal panel Marshall 4 input 50s that were actually louder than my Express, and 100 watt Marshalls are WAY louder if they are healthy examples. I've even played a Ceriatone Express clone that when equiped with 6V6 tubes was STILL louder than my original '89 Express with EL34s in it! FYI both my old Express amps have 6.6k primarys. The gain of an Express however is what can make it seem louder as it's harder to control for sure, but if you get in a band situation you can tell the Express is genuinely about a 35 watt amp.

[Roe]

Actually I think its less than 35w if we speak of clean power, not max output. Measured at the point of breakup it more like 25-30w IMHO

these amps are not particularly loud, they only seem to be because of the aggressive, bright tone and the fast response.

BTW: changed filter caps to BC Vishay 450v - highly recommended!

[JazzGuitarGimp]

Another parameter that must be considered when it comes to amp volume is speaker efficiency:

1. One dB in volume change is considered the smallest increment the human ear can discern. (Mastering engineers notwithstanding )

2. Doubling an amp's output power only increases its output by 3dB. This is a logarithmic relationship; if you start at an output power of 25W with say 110dB SPL output, and then double the power to 50W to get 113 dB SPL, then double again to 100W to get 116 dB SPL - you can see that we only added 25W to get the first 3dB increase, but had to add another 50W to get the second 3dB increase. This is how the human ear responds to changes in volume.

If you compare the same amp, played through two different speakers; the first speaker with an efficiency of 96dB, and the second speaker with an efficiency of 99dB, the apparent volume change will be the same as doubling the amp's output power into the 96dB speaker. This knowledge can serve you well; If you have an amp that is just too loud, you can use a less efficient speaker; likewise, if the amp is not quite loud enough, go for a more efficient speaker.

Another fun fact; when you double the distance from you to your speaker, you lose 6dB in volume.

[jckid649]

I have a Marshall 1960A cabinet. I've used it as an extension with other amps and the Celestion G12T-75's just sounds too "bassy". It's like it muddy's up the sound in a lot of ways. My thoughts, based on some of the things I've read around the Amp Garage forum, is that I will swap out the top 2 with some vintage Pre-Rola Celestion 25W paper cones and swap the 2 bottom ones with some Scumback M75-LHDC. Any thoughts about that combo?

[JazzGuitarGimp]

I don't know enough about the Celestion speakers to comment, but let me ask you this: Does the bass-heavy issue with this cabinet only manifest with the Express Amp? If so, maybe a better approach would be to fine-tune the bypass capacitor values to trim out some of the bass?

[Roe]

the g12-75w is not good with an express

[jckid649]

No it's been bassy with other amps as well.

[jckid649]

I don't know enough about the Celestion speakers to comment, but let me ask you this: Does the bass-heavy issue with this cabinet only manifest with the Express Amp? If so, maybe a better approach would be to fine-tune the bypass capacitor values to trim out some of the bass?

I think I'm gonna hold off on any circuit changes until I get the proper speakers I'm actually gonna use. That's the only way that I know how the amp will really sound with those.