NAD - Marshall content (UPDATE: now NCD)

victorludorum

ICBM said:

Modulus_Amps said:

One should never buy a Marshall 1912, They are really boxy sounding next to a better cabinet.

There's a surprising difference between the ply ones and the MDF ones. The ply ones aren't bad at all - the MDF ones are terrible.

That said, the best I ever heard one sound was a ply one with an EV, used with a Trace Elliot AH150 for a super-compact bass rig...

I made mine out of pine using 1912 dimensions. It's for a small 5w amp which lacks bass, so I made a closed back and it works well for me and for that amp.

Jonathangus

Picked up a nice SV112 cab on t'Bay.  Just given it a quick blast (my neighbours are out).  I reckon the V-Type suits it very nicely indeed.

Jonathangus

You know, it's been said many times on these pages, but there's something really quite magical about the way the Boss SD-1 and GE-7 interact with the 2204 circuit...

ThePrettyDamned

Jonathangus said:

You know, it's been said many times on these pages, but there's something really quite magical about the way the Boss SD-1 and GE-7 interact with the 2204 circuit...

Sd-1 into a Marshall just works so well. 

shaunm

Ok, I am absolutely going to do this to my 2104. 

I only did a thread a couple of weeks ago about doing it. That looks a total game changer. Lugging the combo about is no fun.

My only issue is that I do like the two Black Backs I have in mine and I don’t think running one would be an option. Making a 2x12 sort of makes the idea of lightening the load a waste of time. Maybe a neo creamback 1x12 but I’d sure miss those Blackbacks.

Jonathangus

Go for it, @shaunm .  The head weighs in at around 15 kg, (which is manageable), as opposed to the 30 kg or so for the combo (which isn't).  Not sure how much the chassis weighs on its own, so don't know how much the remaining 2x12 would come to.

ICBM

shaunm said:

My only issue is that I do like the two Black Backs I have in mine and I don’t think running one would be an option. Making a 2x12 sort of makes the idea of lightening the load a waste of time. Maybe a neo creamback 1x12 but I’d sure miss those Blackbacks.

A smaller-size open-back 2x12" with Neo Creambacks shouldn't be too heavy or a million miles from the Blackbacks.

shaunm

@Jonathangus & @ICBM if I do this I think a 1x12 with a Neo Creamback would be great. 

Solves the problem of weight

Emiel

shaunm said:

Ok, I am absolutely going to do this to my 2104. 

I only did a thread a couple of weeks ago about doing it. That looks a total game changer. Lugging the combo about is no fun.

My only issue is that I do like the two Black Backs I have in mine and I don’t think running one would be an option. Making a 2x12 sort of makes the idea of lightening the load a waste of time. Maybe a neo creamback 1x12 but I’d sure miss those Blackbacks.

I've heard the Neo Creamback; sounds great and weights next to nothing!

You can send me your Blackbacks (if they are the G12M 75hz variant) 

THR1LLHAU5

This looks so good! Kind of wishing I'd gone for the 50 watter than the 100 now... that looks really smart in the compact shell. 

ICBM

shaunm said:

@Jonathangus & @ICBM if I do this I think a 1x12 with a Neo Creamback would be great. 

Solves the problem of weight

True, but a 1x12" doesn't sound as good, and a 2x12" isn't *that* much heavier - probably around 50% more, rather than double.

Jonathangus

Just taken delivery of a rotary switch and assorted gubbins to replace the impedance selector.

Supposing I were to fit this myself (it's only four solder joints, after all), how do I do it without blowing myself up?  I need to construct one of these, I think?

https://www.ifixit.com/Guide/Constructing+a+Capacitor+Discharge+Tool/2177

ICBM

Jonathangus said:

Supposing I were to fit this myself (it's only four solder joints, after all), how do I do it without blowing myself up?

It's actually very easy on one of these - simply leave the amp powered up on standby for a couple of minutes. The standby switch is upstream of the rectifier and the first filter cap, so the caps will discharge through the valves.

Beware - this doesn't apply to all amps, although it does to most fairly modern ones.

Jonathangus

ICBM said:

Jonathangus said:

Supposing I were to fit this myself (it's only four solder joints, after all), how do I do it without blowing myself up?

It's actually very easy on one of these - simply leave the amp powered up on standby for a couple of minutes. The standby switch is upstream of the rectifier and the first filter cap, so the caps will discharge through the valves.

Beware - this doesn't apply to all amps, although it does to most fairly modern ones.

So:

Turn on (so power switch lights up).
Leave 2 minutes on Standby (so no sound).
Switch off power and unplug.

That simple?

(I'll still check with a multimeter, just so I'm satisfied.)

ICBM

Jonathangus said:

So:

Turn on (so power switch lights up).
Leave 2 minutes on Standby (so no sound).
Switch off power and unplug.

That simple?

(I'll still check with a multimeter, just so I'm satisfied.)

Yes, that simple.

If you meter the caps you may still find a few volts - maybe even tens - on them after that, since they 'recharge' a bit due to chemical action in the electrolyte, but there isn't enough charge to be dangerous.

Jonathangus

Right, opened up and caps in the region of 3-4 volts.  This is what I've got:



So I think it's black to speaker jacks, grey to 16, green to 8, and purple & yellow to 4.  (Yes, the green needs a bit of heat shrink.)

This is what's going in:



So going clockwise, I want black / grey / green / yellow & purple, yes?

Also, this is the voltage selector.  @ICBM - you thought it might already be hardwired to 240V?

Jonathangus

Right, got it all connected up.  Before I power on, can I just check something - there's now continuity between all three input tags and the output, regardless of the switch position.  Am I right in thinking that this is just via the secondary of the OT, and perfectly normal?

ICBM

Jonathangus said:

So going clockwise, I want black / grey / green / yellow & purple, yes?

Yes, the single terminal should be the black and the other three the different impedances.

Jonathangus said:

Also, this is the voltage selector.  @ICBM - you thought it might already be hardwired to 240V?

The PT has been changed (you knew that) but the selector is still functional. The yellow wire in the middle needs to be moved to the terminal for 240V, which should be the one with the other yellow wire going to it. (Move it and connect both to the same terminal, don't link the middle to the outer.)

Jonathangus said:

Right, got it all connected up.  Before I power on, can I just check something - there's now continuity between all three input tags and the output, regardless of the switch position.  Am I right in thinking that this is just via the secondary of the OT, and perfectly normal?

Yes. The resistance of the whole secondary is a couple of ohms at most, which the meter will see as a connection.

Jonathangus

Fantastic, thanks!

Jonathangus

We have sound!  (And no smoke.).