Class 5 at bedroom volume secret

[ClubAndCountry]

Even if it doesn't blow the transformer, it will still stop the amp working - in a way that the average user can't easily fix for themselves, unless they're happy to open the amp up and clean or straighten the contacts.

It's not a major criticism and there is obviously more than one way of achieving internal/external speaker/headphone switching - I just prefer simpler and more reliable arrangements, even if it requires some things (like disconnecting the speaker when using headphones) to be done manually - especially if it also allows more flexibility. This is one of the common bugbears with a few of the Valvestate models - they actually have a plug-in speaker, but *still* the headphone jack is used to cut off the speakers. And the jack switch is one of the most frequent causes of trouble with these (otherwise quite reliable) amps. This is a simple, non-serious fault - and easy to fix permanently, you just bridge the jack switch, but it shouldn't be like that in the first place!

I'm only a repair tech, not an amp designer, but it does frustrate me to come across the same faults over and over again (in all amps, not just Marshalls) - when they're things that could be eliminated by considering the possible failure modes during the design process...

[SteveD]

I hear what you are saying but this was a design choice based on many factors and service info. There are many faults that can occurr that will not be fixable by the customer in any amp but the important thing is that it will be a simple jack socket replacement if it ever happens. If anyone felt passionate about this it would be a simple job to replace the internal speaker lead with another that instead exited through the bottom vent and plugged into the extension speaker socket.

One of the most common questions we get emailed about is ' I accidentally played my amp without a speaker attached, will I have caused any damage?' Some of these people can't sleep at night until they are reassured.

[parvulesco]

Thanks Steve! I'll probably do just that when I get one. It's not a big deal at all but I'd like to at least try the internal speaker run from the headphone output.

Another question for you—on another forum (The Gear Page), two people have reported a rattling noise that they seem to think is coming from the chassis or the control plate vibrating (they're pretty sure it's not tube rattle). Have you heard of this complaint? It didn't sound like either of the people who had the problem attempted to contact Marshall.

[SteveD]

I hadn't heard about this problem but I will mention it on Monday as something to be checked out. Thanks. I certainly haven't had any prototypes that rattle but once production quantities are available there's always going to be something, that's Murphy's Law.

[slowpokerhino]

And here's a demo vid using the bedroom volume secret.

[youtube][/youtube]

[slowpokerhino]

So, for the sake of discussion, let's say I modded the amp so that the speaker had a regular jack on the back. Could I then use the internal speaker for the bedroom volume secret or would I still need to have a load on the regular speaker jack?

[Kongels]

Of course I certainly would never do it on our higher power amps but I have extensively tested the Class 5 with no load and there was no damage, so I consider any risk to be extremely low.

I believe that is what he is confirming here man.

[ClubAndCountry]

When the switch is set to headphones, you don't need a load - there's an internal dummy load. So if you fit the combo speaker with a cable with a plug on it, you can plug it either into the extension speaker jack (for normal speaker operation, it doesn't matter that it's labeled as an extension) or into the headphone jack for low volume. I'm assuming that the stock cable to the internal speaker will be connected to the board with push-connectors since that's current Marshall practice, so you can remove it completely.

You should be able to get a speaker cable with a right-angle plug on it - it's the same as the part Marshall use on most of their other combos, so you could buy one and keep your amp 'genuine'! If you don't want to order anything special and don't mind soldering to the speaker, at these low power levels a cut-down guitar cable (the sort you get free with a lot of cheap electric guitars) will actually work fine.

[SteveD]

Yes C&C pretty much tells it like it is. The internal speaker lead is indeed on push fit spade connectors both to speaker and to PCB so is easily removed.

You could actually make a speaker lead that had a stereo 1/4" jack plug on one end and terminated with spade connectors for the speaker on the other (if you didn't want to solder anything). Connect the signal to the 'tip' and the ground to the 'sleeve'. Leave the 'ring' disconnected. This way you can plug the jack all the way in for either situation. The new speaker lead can reach through the rear panel opening and just needs to be long enough to plug into either socket.

Note however that if you plug into the headphone out but have the switch in the 'extension speaker' position, the output is unloaded. Now as I said, I have carried out extensive tests on the output being unloaded with no negative results, but I would still encourage people to check and make sure everything is plugged in and switched correctly! It's good practise to get into the habit of doing that anyway.

[ClubAndCountry]

Just for interest, when I had my Studio 15 (which also has this internal dummy load and headphone jack feature), I wired the headphone jack so that the tip was hot as normal and the ground was connected to the *ring* connection, not the ground - with no connection to the actual ground. (This requires replacing the jack because the Studio 15 used a mono jack for the headphones, oddly.) The result of this is that if you plug in a mono plug - ie the one on the speaker cable - it connects as normal except that the ground connection is via the ring position, which makes no difference. But when you use headphones, the hot is connected to the hot of the left phone but the ground is connected to the *hot* of the right phone, with the headphone ground floating... this puts the phones out of phase with each other and creates a huge, spacious headphone sound. Without having seen inside one, I doubt this would be easy on the Class 5 because the headphone jack is board-mounted, but it is theoretically possible if you don't mind cutting traces and re-routing things.

[slowpokerhino]

Bare with me here guys, I can be a little dense at times.
So I could just remove the internal speaker cable and then use either the extension speaker jack (for normal use) or the headphone jack for low volume playing with the internal speaker? Just make sure I have the switch in the right position for the jack I'm plugged into? Cool!

[parvulesco]

Bare with me here guys, I can be a little dense at times.
So I could just remove the internal speaker cable and then use either the extension speaker jack (for normal use) or the headphone jack for low volume playing with the internal speaker? Just make sure I have the switch in the right position for the jack I'm plugged into? Cool!

That's right.

[SteveD]

Bare with me here guys, I can be a little dense at times.
So I could just remove the internal speaker cable and then use either the extension speaker jack (for normal use) or the headphone jack for low volume playing with the internal speaker? Just make sure I have the switch in the right position for the jack I'm plugged into? Cool!

Also remember if you're using a mono speaker jack to only plug it halfway in to the headphone socket.

[Green Manalishi]

I plan on getting one of these, and it looks like I will probably create a lead with a plug for use on the internal speaker. My concern was using the internal speaker with an attenuator, I have a Weber Mini Mass that works great.

SteveD, can I leave the internal leads attached, then also attach another lead for use with an attenuator? What I mean is if I leave them both connected to the speaker, but when I want to use an attenuator, I use the ext plug into the attenuator then to the lead I added, or decide just to use the normal internal wiring, would that work? Or would it cause an issue by both being attached?

How would that sound compared to using the headphone trick?

[SteveD]

You would have to disconnect the internal speaker lead I'm afraid but its very easy to do.