As title,

 

A lot of people (and the manual) on the net seem insistent that you need to have a cabinet attached to the Marshall JMD50 Guitar Amp Head in order to use it or it will blow the amp/headphones.

This is the amp:

http://www.gear4music.com/Guitar-and-Bass/Marshall-JMD50-50W-Guitar-Amp-Head/MJ6

 

Can you not just use it with a pair of headphones?

 

I bought it as it was a bargain and I wont be able to buy a cab till christmas, just wanted to clear it up weather or not I'll be able to use it with just a pair of headphones??

 

Cheers

 

tris

This is from the amp's manual:

"NEVER use your amp without a (speaker) load attached when the standby switch is in the 'On' position."

 

Maybe the local pawn shop has an old beater cabinet you can use?

Already ordered the above, just double checking.

 

Someone pointed this on the first page that I missed before:

 

When the amplifier is in standby mode the whole preamplifiersection is still functional whilst the power amplifierremains in a standby status. This allows the amplifier to beused for silent recording or pre-amplification purposes.Only when the Standby switch (9) is set to ‘OFF’ can theamplifier be used without a load. Always ensure a load isconnected when switching the Standby switch on.

 

 

So I presume I can turn the amp on, keep the standby switch off, and plug in some headphones or take a xlr-3/4" jack lead from the emulated out on the rear of the JMD50 to the line in on my pc or av system?

 

tris

Yep, that's exactly what that standby switch is for.

 

You can blow a tube amp without having the speaker attached. But that amp has a transistor preamp.

Ahh, so it should be fine using headphones or the emulated line out for now then as long as I make sure I don't switch the standby to the 'on' position?

 

Cheers

 

tris

Got it through yesterday :)

 

I've tried an emulated line out from xlr - 6.3mm - 3.5mm adapter to my av receivers 3.5mm aux in jack and also normal desktop speakers but get no sound at all.

 

Hoping I haven't got a dud unit. I have made sure I have the standby switch set to 'on' and all the pre amp setting should still work according to the manual for the 'silent' recording mode.

 

The wife is picking up a 3.5mm to 6.3mm adapter for the headphones today, so hopefully that will work.

 

tris

@@Rockinbiscuit You're using the wrong output -- the amp has a dedicated headphone output.

Just to add a little to this topic ... There are ways to simulate loads, but generic ones are expensive.  The following one can simulate cabinet loads, but if you are handy with electronics, you can build your own that is exactly matched to your amp.  It will be much cheaper to build one, but you have to do the calculations exactly right, or you can blow your amp.  

 

http://www.thdelectronics.com/product_page_hotplate.html

 

Just search for "simulated speaker load" for lots of discussions on the topic like the following page.

 

http://www.duncanamps.com/technical/dummyload.html

Ahh, thought it might work from the xlr emulated output too to the av receiver  :oops:

 

Just been in touch with the wife and she's got no clue what she's looking for, so it looks like I'll have to order a 3.5mm-6.3mm jack from the net, at least I'll be able to use headphones then.

 

Do you think going from the headphone jack to the 3.5mm jack on my av receiver would be ok and work? If so I can pick up a these:

http://www.amazon.co.uk/3-5mm-Male-Stereo-Audio-Cable/dp/B000Q6LT26/ref=sr_1_3?rps=1&ie=UTF8&qid=1401373427&sr=8-3&keywords=6.3mm+to+3.5mm+cable

and 2x

http://www.amazon.co.uk/Adaptor-stereo-socket-blister-packed/dp/B0016HHYQO/ref=sr_1_16?rps=1&ie=UTF8&qid=1401373479&sr=8-16&keywords=3.5mm+to+6.5mm

 

That way I'd have two adapters for use with the cable from the headphone socket to the 3.5mm aux in on my av receiver and also be able to use one when using headphones of course :)

 

Cheers

 

tris

@@Rockinbiscuit I don't see why you couldn't use the headphone into your receiver, sure. Just turn the volume down at first. But instead of that you should be able to run the preamp out signal into your receiver.

 

Tell you wife you want an adaptor to turn a little one into a big one. I'm sure she'll figure it out :-P

@@Rockinbiscuit I don't see why you couldn't use the headphone into your receiver, sure. Just turn the volume down at first. But instead of that you should be able to run the preamp out signal into your receiver.

 

Tell you wife you want an adaptor to turn a little one into a big one. I'm sure she'll figure it out :-P

 

Not sure she'll be pleased with the results :lol:

 

Ordered one off the amazon now, it'll arrive tomorrow. Much quicker/easier than trying to explain it to the wife :roll:

 

Well, I got two and a 5m 3.5mm-3.5mm cable (will be used for other things too), so hopefully that will work from headphones and/or pre amp out.

 

Just had a look at the switches, here's a pic for ref so everyone sees what they are:

 

http://img.photobucket.com/albums/v200/nero041001/Guitar/IMG_0738Copy.jpg

 

So, to clear this up:

1. left switch = do not turn on without speaker cabinet selected (Keep it off)?

2. right switch = turn this switch on to use headphones, emulated line out etc....?

 

If that's right, then I've been turning the amp on (the left switch), which I shouldn't be doing if the above is correct and leaving the right switch off....

 

I'll add that when I do turn the left switch on, the glass bulby things in the back begin to light up.

3. I presume thats not meant to be happening if I just want the use of the xlr/headphones etc....?

4. Or are we meant to switch both switches to the on position?

 

I had a red power led lit up on the front as I turned the left switch on and kept the right switch at the off position.

 

It is strange, after looking at it properly, the right switch looks as if it's labelled to say that turning it on turns the standby mode on. The manual doesn't help much, there's not much detail in there.

 

Don't mind me, I get confused a lot.... still getting used to this sort of equipment, it's a little different to my usual home cinema enthusiast background.

 

tris

Leave the standby in the OFF position (pressed toward the top). Turn on the power switch -- it makes sense that there's a slight glow, because the purpose of the standby is to preheat the tubes before giving them full power.  But you'd need power to use the preamp part, obviously.

 

You ought to look around for a cabinet though -- you need one rated at 8 Ohms. (But you can also use one rated at 16 Ohms -- 8 ohms seem to be more common though) I bought one new from Thomann for only 100 euros a couple of years back, so you'll definitely be able to find something used for much less. That should be enough to hold you until you can get a 'real' cabinet (I'm going to assume you'll want to match the head with a Marshall cabinet).

 

Maybe ask around -- you'll likely find someone with a couple of cabs gathering dust in a closet. (I used mine exactly twice, hated lugging the thing around).

 

This one from Thomann would do it: http://www.thomann.de/fr/harley_benton_g112.htm

Leave the standby in the OFF position (pressed toward the top). Turn on the power switch -- it makes sense that there's a slight glow, because the purpose of the standby is to preheat the tubes before giving them full power.  But you'd need power to use the preamp part, obviously.

 

You ought to look around for a cabinet though -- you need one rated at 8 Ohms. (But you can also use one rated at 16 Ohms -- 8 ohms seem to be more common though) I bought one new from Thomann for only 100 euros a couple of years back, so you'll definitely be able to find something used for much less. That should be enough to hold you until you can get a 'real' cabinet (I'm going to assume you'll want to match the head with a Marshall cabinet).

 

Maybe ask around -- you'll likely find someone with a couple of cabs gathering dust in a closet. (I used mine exactly twice, hated lugging the thing around).

 

This one from Thomann would do it: http://www.thomann.de/fr/harley_benton_g112.htm

 

Cheers mate.

 

I found the problem in the end with using the xlr emulateed out to my av receiver.... I had forgot that I needed to turn the volume nearest the gain up.... and completely forgot to turn the gain up at all :roll:

 

Did I mention how new am am to this type of equipment? ;)  At least I have some sound now.

 

I'm making sure I don't double dip when it comes to cabinets. I have seen and heard a few second hand ones at a shop in town, they all have speakers that crackle, which is why I was looking for a way round using what I have, which I have done now which is good :)

 

Thanks for the link, been talking extensively on about all this on the Avforums, that one popped up, but then I saw this one which I have my eye on:

http://www.thomann.de/gb/harley_benton_g212_vintage.htm

 

I was thinking about buying a couple of vintage 30's and building my own box.... though I don't know how that would turn out, plus the G212 uses the same speakers which I was thinking of, but if I bought them on their own they would have been a couple of quid more expensive than buying a ready built cab with them both in.

I'd flip the switch on that cab to 8ohm mono and have both speakers working that way with that cab.

 

There is a Marshall 2x12 cab for around £280 with the Celestion Seventy 80's in there, so I'd be paying an extra £120 for inferior speakers than what is in the G212 and a plastic brand name stuck on the cabinet. I listened to loads of celestions around my budget and the vintage 30's came out on top (to my ear anyway), hence why that is the cab I'm looking to buy :)

 

tris

I had that cabinet (I don't believe mine had Celestions though -- mine cost a lot less than that), I was using it paired to a Laney VC15, because the built-in speaker was pretty bad (I had a two-amp setup with a Vox AC30 on the other side). Pretty decent cab for the price, for sure.

 

It depends on what you'll be doing -- if this is just for playing at home, then sure, this one will be fine. But they cut a lot of corners to get the price of those Harley Benton -- for one thing, the cabinet is wrapped in paper, basically. It'll rip if you just look at it the wrong way. All the other bits (feet, corner protectors, etc) are cheap plastic. Not a big deal if it's never going to leave your house. But if you dropped it on the way to a gig (and something always gets dropped), it'd probably just shatter. 

 

Also, I admit that I'm brand-conscious when it comes to gear. The only thing in my life where the brand matters to me. I should have held out and gotten the Vox cabinet I wanted. But I ended up selling both amps anyway. :-P

There are two of them, one has the vinatege 30's in it, the other doesn't :)

 

Without the vintage 30's:

http://www.thomann.de/gb/harley_benton_g212.htm

 

and the one with them:

http://www.thomann.de/gb/harley_benton_g212_vintage.htm

 

It's a shame they are not very good at answering emails, and at 25p a minute to call, it's a bit costly to give them a call for me (I talk too much).

 

I'm in the uk, and been trying to find as good bang for buck as the german site that sells them, but no luck so far.

 

I'll be at home mainly, so it'll be sat nice and comfy most of the time :)

 

tris