Easy way to cure a scratchy voice coil in a guitar speaker

Posted on 2 CommentsPosted in Amps

I recently had a problem with a Music Man HD130 amp (the one Mark Knopfler used in the early days of Dire Straits). One speaker was creating a scratchy, distorted sound, surprisingly only at very low volume while it was fine at medium or high volume. I managed to cure it with an easy trick, nothing too special or secret but nevertheless something I want to share in case someone runs into similar problems with his amp.

When I removed the speaker to have a closer look at what might be wrong with it, I immediately noticed that infamous scratchiness when moving the cone carefull with two fingers. It was worse when pushing more on particular places while it disappeared when doing so at some other spots. I quickly came to the suspect that the problem came from “standing” upright for decades (it was a 1976 amp with original speakers). The voice coil is not really a heavy part but still it has some small weight, and after years this weight can deform the cone slightly so that the voice coil scratches on one side. For the same reason you should always store speakers horizontally but who stores a combo amp or a speaker cabinet this way?

mm-amp-speakers
The speakers after turning and swapping – the two ‘Music Men’ on those stickers with their heads down now – but the speakers feel happy again

The solution was very easy and inexpensive, even without any costs at all: all I had to do was turning the speaker for 180 degrees, so that what pointed to the top became the bottom end. I did the same with the second speaker, not only to prevent similar problems with it in the future but also to make the connectors of both speakers look to the middle between the speakers again, which means I also swapped the left and the right speakers. Hopefully it will work fine for the next 41 years now πŸ™‚

Of course this easy fix does not always work, if the cone or the voice coil is damaged only a recone job will help. But before doing so you should give it a try.

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Strange guitar sound on the Werchter 1981 recording – Did Mark mix direct out and microphone?

Posted on 5 CommentsPosted in Amps, Dire Straits/ Mark Knopfler live pictures and videos, Mark Knopfler gear

On July 5, 1981, Dire Straits played on the Werchter festival in Belgium. The concert was broadcasted on the radio and on TV and is one of the very few soundboard recordings from the 1980/81 On Location tour.

There is one thing that always strikes me about that recording: Mark’s guitar sound was what I’d call ‘strange’, and completely different from all other recordings of the same tour we have (and there are many…). It had a very different, harsh kind of treble. To my ears it sounds like a direct out of the amp, and not like the mic’ed guitar speaker you would expect here.

You will probably know that a typical guitar speaker is a ‘woofer’, a loudspeaker aimed mainly at low and midrange frequencies. It has a pronounced treble roll off, which means it hardly produces high treble frequencies over maybe 6 kHz. For this reason it strongly colours the sound; it automatically filters out unwanted harsh, crisp frequencies. Without the guitar speaker especially a distorted guitar would not sound as we all expect it to sound. For this reason there are – unlike in a PA system – no tweeters (high frequency speakers) in a guitar cabinet.

celestion-graph
Typical frequency response of a guitar speaker

What is strange about the Werchter guitar sound is that I feel to hear exactly these frequencies that should not be there. How is this possible, as we know that Mark of course used guitar speakers on this tour, Marshall 4 x 12″ cabinets to be precise? And on all other recordings from the tour the sound is not like on this one.

It seems unlikely to me that they had a completely different setup for this day – especially as Mark’s live sound required a full effect rack that is not easy to substitute. And even if a guitar speaker suddenly fails, you can simply put the microphone in front of another one – there are four of them in each cabinet! The only theory that makes sense to me is that there was a second signal path involved, one without the guitar speakers. This ‘direct out’ was blended with the signal from the microphones/speakers. One possible reason to do so might be that this way you have more high end and low end to enrich the ‘normal’ sound of the speakers to a desired extend.

I guess for the radio/TV broadcast the concert was mixed separatedly from the PA mix, most likely by engineers of the broadcasters . This is not unusual, you normally want to mix to a much wider stereo signal than you’d do for a PA system. And the sound guys responsible for this mix simply used the direct signal rather than the mic’ed speakers signal, they maybe did simply not know why there were two different sources and what to do with these.

Interestingly the youtube video of this concert includes a few songs that were missing on the radio/TV broadcast. These came from an audience recording in bad quality (see video description), but you can clearly hear that on these songs the sound is very much as it is on all other recordings from the tour, not as thin and trebly as on the radio mix!

Of course this is speculation but if I am right indeed it tells us something about the way Mark created his stage sound on this tour (or even on others, too ??) .

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The Mark Knopfler Rig on the 2015 Tracker Tour

Posted on 10 CommentsPosted in Amps, Effects, Mark Knopfler gear

Guy Fletcher was so kind to post a picture of Mark’s effect rack in his tour diary . With this blog post I am trying to explain a bit what we can see in the picture, and some details we can conclude from what we see.

But first here is what Guy wrote on it:

As has been requested on more than one occasion, here is some inside info on Mark’s guitar rig. Glenn Saggers station. As anyone who has seen the show will realise, there are a lot of guitar changes not only for Mark but for everyone. Mr. Saggers works flat out during the show, tuning and preparing amp setups and delivering instruments to Mark flawlessly through the evening. I really don’t know how he does it as every amp sound and effects setting is recalled meticulously for each and every song. Two Reinhardt amps are used in leap-frog fashion and whilst we are performing one song, the next one is being set up. Also there is the ’59 Bassman (offstage) which is used for slide along with Mark’s β€˜Dano’ and of course the Tone King which resides onstage in between the two 4×12 cabinets. The Tone King settings remain constant during the show.

MKGEARmontage-700
Picture courtesy Guy Fletcher (guyfletcher.co.uk)

Well, Mark uses four different amps on this tour. While Guy speaks of two Reinhardts, what we see is one Reinhardt Talyn (top left) and a Komet Linda (bottom left). Then we have a Tone King on stage, and a 1959 Fender Bassman off-stage. The tone King is for some clean guitar sounds, and the Bassman for slide with the Danelectro guitar.

Guy says two Reinhardts “are used in leap-frog fashion”, meaning one is in use while the other is prepared for the next song. I guess the same is true for the Reinhardt and the Komet we see here. However, this also means that when Mark wants to play two songs that both require e.g. the Komet but with different settings, he has to play one other song with a different amp in between so that his technician Glenn Saggers has time to prepare all settings. Or Glenn has to be very quick and change the settings in a short break while Mark e.g. announces the next song.

The Effect Rack

Some devices in the rack are the same as on previous tour (compare to the 2008 rack): we see the familiar D.A.V. electronis pre-amps (with EQ, possibly some limiting/compressing, exact model unsure, probably custom made), the same switching units, and the TC Electronis 2290 delay. There is a Furman power conditioner again, this time at the bottom of the rack. It seems to be this model.

We see that all devices – except a compressor – are arranged in pairs. Theoretically this can be for several reasons: one for each “leap-frog pair” so that Glenn can adjust the device for the next song, one for each stereo channel, or one in use and one as a spare in case of some defect.

We can’t know for sure, but there is one detail in the pictures that makes one think it is the third option: the power LEDs on some devices (the lower of the two D.A.V. electronics pre-amps and lower of the switching units) are off, so I guess these are spares.

There is one ‘new’ effect – new does not sound right for a classic that was introduced in the 1970ies – a dbx 160A mono compressor. If I had to guess I would say it is for clean slide guitars.

Let’s have a look at the switching system:

On the left we have a gain control – I guess the D.A.V. comes first so the gain will not do that much, next five insert slots, a mute button, and then five outputs.

Insert1:
unsure if green LED is on or off, no label, might be unused, has an additional mini switch (can also be a ‘bypass all inserts’)

Insert2:
labelled with FX (effects). Which effects? All the ones in the rack are in the other inserts (see below), so I guess this is for effects on stage. This makes sense as it is the first insert in the line.

Insert3:
labbeled with VP (volume pedal). The Ernie Ball volume pedal is used in the effect insert, just like on previous tours. Mark’s guitar does not go directly into the device to his feet as you might assume, but to the rack, then it goes back to the volume pedal, and from the volume pedal back to the rack. You need long cables, but as the signal is low impedance here this does not matter really.

Insert4:
labelled dbx, so it is the 160A compressor

Insert5:
the TC 2290

It seems each insert can be active (green LED on) or bypassed here.

The signal can then be routed to any of the four amps.

If you see more details, or want to speculate what the little boxes on topf of the Talyn and Linda amps (labelled with Talyn and Linda) are, share your thought in a comment to this blog post (no registration required).

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