Roland JC-120H Head

[sean106alcon]

I just got one and the **** thing is so loud I cannot even get it pass like 6:30-7 O'clock with out it being ear shattering thus my neighbors want to kill me.

I am using it through a modded Roadster 2x12 wired to take the two 8 Ohm inputs for full stereo chorus (cab has two 16 ohm V 30's). 4nkam on the board has the same head and he said he can get it even up to around 11 O' Clock and is fine. Is mine a dud? I even tried a THD hot plate but those are really meant for one set of speakers and I tried it and got no sound. Any one have some input?

I have two Diezel 4x12's. But only one here at my place as I keep the other at my vocalists house for gigs when we play out he brings it. Maybe it is meant for two 4x12's and not a modded 2x12? Thanks!

Are they meant to be this loud?

 

[Mongo1]

No doubt, that head can be smokin' loud, and crystal clean! That's basically the same amp configuation as the original standard JC120, which uses (2) 12's. Taking into consideration that it's using a seperate 60 watt amp on each speaker. That equates to LOUD on anyones scale...

 

[sean106alcon]

No doubt, that head can be smokin' loud, and crystal clean! That's basically the same amp configuation as the original standard JC120, which uses (2) 12's. Taking into consideration that it's using a seperate 60 watt amp on each speaker. That equates to LOUD on anyones scale...

I know man. Is there anyway to tone it down so like you can at least get it to 11-12 noon and it not be ear shattering? But I am assuming since it is SS it will sound the same at 6:30-7 o' Clock as 11 O'Clock? Thanks.

 

[Mongo1]

Maybe use less efficient speakers?

 

[sean106alcon]

Maybe use less efficient speakers?

Huh? :?:

 

[Mongo1]

An 8ohm speaker that is 'highly efficient' will sound louder than a 'lesser efficient' speaker at the same wattage.

Someone else here may be able to elaborate further as to why, and whether there is a standard way to determine a given speakers efficiency rating.

 

[t0aj15]

First of all DO NOT use a THD Hot Plate with ANY ss amp, here is a quote from the faq section of the Hot Plate manual:

"Q. Can I use the Hot Plate with a solid state amp?
A. NO! The Hot Plate and the power section of the amp will be damaged if the amp does
not use output tubes. Thus, even if an amp has preamp tubes, it CANNOT be used with
the Hot Plate if it has a solid state output section. However, an amp that has a solid-state
pre-amp section but a tube output section CAN be used with the Hot Plate."

Second yes using less efficient speakers will help with a 'too loud' amp. For example if your using a pair of speakers that have an efficiency rating of 100 db and switch to a pair that only have an efficiency rating of 97 db that 3 db drop will effectively cut the perceived volume in half. You can usually get the db efficiency ratings from the manufacturers website. For instance your V30's have a sensitivity (efficiency) rating of 100 db so switching to speakers that are only 97-98 db (or less) will cut the volume. Also running higher speaker impedence (like 16 ohms instead of 8 ohms) will cut back on the amps ability to "blow your brains out".

 

[sean106alcon]

First of all DO NOT use a THD Hot Plate with ANY ss amp, here is a quote from the faq section of the Hot Plate manual:

"Q. Can I use the Hot Plate with a solid state amp?
A. NO! The Hot Plate and the power section of the amp will be damaged if the amp does
not use output tubes. Thus, even if an amp has preamp tubes, it CANNOT be used with
the Hot Plate if it has a solid state output section. However, an amp that has a solid-state
pre-amp section but a tube output section CAN be used with the Hot Plate."

Second yes using less efficient speakers will help with a 'too loud' amp. For example if your using a pair of speakers that have an efficiency rating of 100 db and switch to a pair that only have an efficiency rating of 97 db that 3 db drop will effectively cut the perceived volume in half. You can usually get the db efficiency ratings from the manufacturers website. For insance your V30's have a sensitivity (efficiency) rating of 100 db so switching to speakers that are only 97-98 db (or less) will cut the volume. Also running higher speaker impedence (like 16 ohms instead of 8 ohms) will cut back on the amps ability to "blow your brains out".

Thanks for the input man. The speakers in the cab are 16 ohm. So technically would it not take more power to push them? Just thinking out loud. Say if it had 4 ohm V30's would those be more sensitive and easier to push with less power? I would think since I have 16 ohm V30's inside it would take more volume to push them. Thanks guys.

 

[t0aj15]

Thanks for the input man. The speakers in the cab are 16 ohm. So technically would it not take more power to push them? Just thinking out loud. Say if it had 4 ohm V30's would those be more sensitive and easier to push with less power? I would think since I have 16 ohm V30's inside it would take more volume to push them. Thanks guys.

I'm not familiar with the JC 120 H but if the output is stereo (like the combo version) then your Mesa cab should be wired in stereo also, so that each of the 16 ohm speakers plugs into it's own amp output channel. If your already doing this then there's not much else you can do to lower the volume of that setup short of throwing a heavy blanket over it. Your next best choice is to find speakers less sensitive (efficient) then what you have now.

BTW, yes with ss amps 4 ohm speakers will be louder then 16 ohm speakers of the same kind at the same volume setting.

 

[sean106alcon]

Thanks for the input man. The speakers in the cab are 16 ohm. So technically would it not take more power to push them? Just thinking out loud. Say if it had 4 ohm V30's would those be more sensitive and easier to push with less power? I would think since I have 16 ohm V30's inside it would take more volume to push them. Thanks guys.

I'm not familiar with the JC 120 H but if the output is stereo (like the combo version) then your Mesa cab should be wired in stereo also, so that each of the 16 ohm speakers plugs into it's own amp output channel. If your already doing this then there's not much else you can do to lower the volume of that setup short of throwing a heavy blanket over it. Your next best choice is to find speakers less sensitive (efficient) then what you have now.

BTW, yes with ss amps 4 ohm speakers will be louder then 16 ohm speakers of the same kind at the same volume setting.

yeah is exactly have it set up. Stereo outs into to inputs of a Mesa Roadster 2x12. Oh well will just deal with it till I move again :lol:

 

[kingston11]

Sean, are you trying to turn it up so that it overdrives? Its a solid state, so I wouldnt expect that to happen. These JC-120 are loud CLEAN amps. Its not going to get crunchier or sweeter the louder you play. Its only for clean playing.
If you want to sell it, let me know. Im looking for one. lol. Mine was stolen long ago, and I miss it.

 

[CoG]

hahaha yeah and if he won't buy it I will

 

[kingston11]

hahaha yeah and if he won't buy it I will

I dont want it. lol.
They are too expensive for what it is. I am searching for a Peavey Stereo Chorus 400 instead. I have 2 near where I live that are less than 200 bucks, come with speakers, and footswitch. Its like an exact copy of the Roland JC-120, but WAY more versatile and controlling!

 

[MrMarkIII]

Also, find out what the speaker impedance is supposed to be. It should say something by the speaker jacks on the back of the head. Unlike tube amps, solid state amps are very sensitive to mis-matches and you will blow it up. Glad you bought it, huh?

 

[sean106alcon]

Also, find out what the speaker impedance is supposed to be. It should say something by the speaker jacks on the back of the head. Unlike tube amps, solid state amps are very sensitive to mis-matches and you will blow it up. Glad you bought it, huh?

LOL yeah I am totally glad I bought it. I love the tone of the JC120H heads. Plus one day when I am back in a house I can blast it. Maybe I should get my other Diezel 4x12 which has a 8 ohm input on each and run them space apart if I have a bad mismatch.

How I modded it and was told was a safe mismatch......is converted the back of a roadster cab to 2 8 ohm inputs into the V30's Now the V's 30's when I opened it up are 16ohm V30's? bad mismatch? If so do you think buying to 8ohm V30's might fix the volume issue?

I am not trying to get ANY grit just that nice fanboy Hetfield clean tone. I just basically A/Bing it with my Mark V. So Mark V for dirties and lead, the JC-120H for cleans. But again the issue of not even getting past 7 O'Clock it is ear shattering. I recall that to with my old combo also it was uber loud. but was able to raise the volume to at least 11 O'Clock....but then again I was living in house with my Ex. No I am in an apt so get kill the neighbors

Thanks as always guys.

 

[sean106alcon]

here are some high rez pix of the mod and connections:
Ignore the wires in the first one as that was before I clipped him to put the adapter plate on to make em stereo as the original back plate only had one 8 ohm input so the JC-120 had no chorus (or totally off chorus)
Thanks again guys!

 

[sean106alcon]

Forget solved.


So I realized I had a POD XT in my gear closet. Plugged the guitar into it and then into input.......raised the volume to about 9-10 O'Clock on the JC-120...then used the output and channel volume to adjust my level so I have full tone and can play at any volume and still get that JC-120H chime plus a compressor, plus the Pod Chorus added.....plus a second set of Bass, treble, mid etc. knobs. I dunno why it never dawned on me LOL it is midnight and I was playing at low volume and still getting that full Hetfield fanboy open G chime. LOL :lol:

 

[pirre81]

Maybe some vids ?

 

[sean106alcon]

Maybe some vids ?

yeah when I get a chance. I used to make a ton of gear vids. But just so busy this past two years. I will try to get one up. Sounds great now.

Even Hetfield only has his volume on his JH-120H head to like 11 O' Clock so yeah these things are LOUD.

Pic by 4nkam.

 

[pirre81]

I'm looking forward for it... Just got VH4 and concidering a new cab. Any suggestions?