Jcm 900 dual reverb

billando

Does anyone use an attenuator with a Jcm 900 dual reverb for gigs? If anyone has tried this do they prefer the attenuated sound or master low? 

billando

I find at drummer level I can get the master to 3.5 (gain at 2pm). I think sweet spot on these is around 6 on the master but when I'm there I have to attenuate a little. I have had nearly every attenuator over the years (ps2 now) and it def takes a life from the tone. Just wondering if anyone uses an attenuator with the jcm 900 amps.  

timmysoft

Never needed it in a 900, I find the volume control adequate 

billando

I find it good too but have u compared it in a live situation with an attenuator? 

timmysoft

billando said:

I find it good too but have u compared it in a live situation with an attenuator? 

Yes, I don’t think it needed it. I use to use a 4500 head into a 412 and never needed any sort of attenuation. 

Are you bridging the fx loop with a patch cable and winding up the fx mix to about  11 o’clock?

ICBM

timmysoft said:

Are you bridging the fx loop with a patch cable and winding up the fx mix to about  11 o’clock?

This really doesn’t do anything. There are no extra components in the loop circuit apart from the level pot and some resistors, which are bypassed when there’s nothing in the loop. You may get a very slight change in volume due to the two halves of the level pot not tracking each other accurately, but that's all.

(The bit inside the dotted box at top right and middle left.)

timmysoft

ICBM said:

timmysoft said:

Are you bridging the fx loop with a patch cable and winding up the fx mix to about  11 o’clock?

This really doesn’t do anything. There are no extra components in the loop circuit apart from the level pot and some resistors, which are bypassed when there’s nothing in the loop. You may get a very slight change in volume due to the two halves of the level pot not tracking each other accurately, but that's all.

(The bit inside the dotted box at top right and middle left.)

It does something different to the sound, it adds low end and adds a responsiveness to pick dynamics.

ICBM

timmysoft said:

It does something different to the sound, it adds low end and adds a responsiveness to pick dynamics.

With respect, you’re imagining it. There is no additional circuitry which could do that.

At most, it’s increasing the signal level very slightly which will have exactly the same effect as turning up the master volume by the same amount.

It’s not even the same as something like the Fender Hotrod which uses an IC for the send and return.

Maynehead

Didn’t Randall Smith say that “every single part is a tone control in an amplifier”? 

timmysoft

ICBM said:

timmysoft said:

It does something different to the sound, it adds low end and adds a responsiveness to pick dynamics.

With respect, you’re imagining it. There is no additional circuitry which could do that.

At most, it’s increasing the signal level very slightly which will have exactly the same effect as turning up the master volume by the same amount.

It’s not even the same as something like the Fender Hotrod which uses an IC for the send and return.

Not imagining it at all, it’s something a lot of 900 owners do and have done since the amps release.

ICBM

timmysoft said:

Not imagining it at all, it’s something a lot of 900 owners do and have done since the amps release.

Just look at the schematic and explain to me how it can be so.

There are no active components in the FX loop. All you’re doing, at most, is increasing the volume slightly.

octatonic

@ICBM is correct.

timmysoft

ICBM said:

timmysoft said:

Not imagining it at all, it’s something a lot of 900 owners do and have done since the amps release.

Just look at the schematic and explain to me how it can be so.

There are no active components in the FX loop. All you’re doing, at most, is increasing the volume slightly.

I don’t need to read a schematic, I can hear a difference as have many 900 users over the years.

olafgarten

timmysoft said:

ICBM said:

timmysoft said:

Not imagining it at all, it’s something a lot of 900 owners do and have done since the amps release.

Just look at the schematic and explain to me how it can be so.

There are no active components in the FX loop. All you’re doing, at most, is increasing the volume slightly.

I don’t need to read a schematic, I can hear a difference as have many 900 users over the years.

It's physically impossible to hear a difference. 

ICBM

Thousands of people genuinely believe they can hear a difference between mains cables and different brands of caps in guitar too, but they’re still imagining it.

There may be a small volume change - the loop has two level pots (on the same physical shaft) which work in opposite directions, and some extra resistors which are intended to maintain the same signal level as the pot is turned but don’t quite, so what you may be hearing is the well-known psycho-acoustic effect that a slightly louder sound sounds ‘better’ rather than louder - but there isn’t any real change that wouldn’t occur if you just turned the volume up by the same amount.

octatonic

This is how religion managed to take hold.

timmysoft

ICBM said:

Thousands of people genuinely believe they can hear a difference between mains cables and different brands of caps in guitar too, but they’re still imagining it.

I’d rather trust my ears and first hand experience than a man in Scotland who has no time to actually fix amps because he’s too busy posting on Internet forums.

ICBM

timmysoft said:

I’d rather trust my ears and first hand experience than a man in Scotland who has no time to actually fix amps because he’s too busy posting on Internet forums.

Lol

I also have a lot of first-hand experience with these amps, *and* I can read a schematic .

octatonic

timmysoft said:

ICBM said:

Thousands of people genuinely believe they can hear a difference between mains cables and different brands of caps in guitar too, but they’re still imagining it.

I’d rather trust my ears and first hand experience than a man in Scotland who has no time to actually fix amps because he’s too busy posting on Internet forums.

poopot

have you tried pulling two of the power valves out and running it at half power?

fretmeister

timmysoft said:

ICBM said:

Thousands of people genuinely believe they can hear a difference between mains cables and different brands of caps in guitar too, but they’re still imagining it.

I’d rather trust my ears and first hand experience than a man in Scotland who has no time to actually fix amps because he’s too busy posting on Internet forums.

ha ha hahahahahaha!

You're the reason that audiotard IEC power cables can charge £1500 for a kettle lead!

If it doesn't show up on a 'scope you ears cannot hear it.