Guitar Gear Forum

HavPT wrote:Hi guys I'm new here and found this thread today, I'm about to buy a JCA100HDM amp + JCA24s cabinet bundle. Can someone pls tell me if the digitech multifx RP1000 will work fine on 4 cable method, this is mostly to use the amp loop with some effects running on the amp fx loop. Has anyone tried this or know if it will gonna work?


Thanks

Have not tried a RP1000 in the loop. The RP1000 manual lists the amp loop level at 8dbu maximum. The SLO/JC loops are typically +4dbu nominal IIRC. This may work fine depending on your preamp level on the JC. Give it a shot, if you get clipping on the peaks you may need to attenuate the send on the JC and then boost the levels on the RP1000 amp out to the return.

Thanks guys, I think I'll give it a shot. Man I hate to buy an amp before I try but I can't afford anything above this price range at the moment...

Why this amp? I need a clean channel (I mean clean it's a covers band and we play some songs that require clean) and a distortion channel (and I really like what I've been heard on youtube about this channel on this JC amps), do you think I could save around 150€ and buy the JCA50H? I'm affraid I can't have that clean volume that keeps up with the drummer with the JC50... Bundle difference is 499€ and 645€. I need portability too and any of these two heads are about the same weight and exact dimensions.

Well "attenuate the send" is this a modification in the amp?

Clean is definitely tough with the stock JCAs. My 50H is modded with a clean switch that cuts the volume considerably when engaged. I can get the overall volume back up some, but it'd probably be better with the 100 watt's headroom.

Without the mod, you're looking at running all volume / little gain, and may still have to cut guitar output volume to get it clean enough.

I'd be concerned, if it were me. I think you really need to try it out to be sure, and take your pedalboard with you.

I understand that but the problem is that no stores around here in Portugal with Jet City amps. I wish I could try one.

I think I can have the same problem with the JC50h and rp1000 4Cm right?

HavPT wrote:Thanks guys, I think I'll give it a shot. Man I hate to buy an amp before I try but I can't afford anything above this price range at the moment...

Why this amp? I need a clean channel (I mean clean it's a covers band and we play some songs that require clean) and a distortion channel (and I really like what I've been heard on youtube about this channel on this JC amps), do you think I could save around 150€ and buy the JCA50H? I'm affraid I can't have that clean volume that keeps up with the drummer with the JC50... Bundle difference is 499€ and 645€. I need portability too and any of these two heads are about the same weight and exact dimensions.

Well "attenuate the send" is this a modification in the amp?

There is a standard modification for the SLO/JC loop. The mod drops the send level to 0dbu and raises the return level to compensate for the lower send signal.
http://www.ampbooks.com/home/classic-ci ... ematic.jpg

The mod requires two components to be added to the amp. If the RP1000 is capable of boosting the return signal enough you could get away with just the send level mod. If you are opposed to modifying the amp you can buy a loop adapter device like this: http://www.toursupply.com/product-p/sa-1.htm . Probably less than having a tech mod the amp for you.

HavPT wrote:I understand that but the problem is that no stores around here in Portugal with Jet City amps. I wish I could try one.

I think I can have the same problem with the JC50h and rp1000 4Cm right?

The 50h and 100h both have the same loop design, so yes the loop problem would be the same. As far as the clean sound on the crunch channel if you are ok with " rock clean" try using an EQ in front when using the crunch channel to help dial it in.

ironman28 wrote:

HavPT wrote:I understand that but the problem is that no stores around here in Portugal with Jet City amps. I wish I could try one.

I think I can have the same problem with the JC50h and rp1000 4Cm right?

The 50h and 100h both have the same loop design, so yes the loop problem would be the same. As far as the clean sound on the crunch channel if you are ok with " rock clean" try using an EQ in front when using the crunch channel to help dial it in.

which one? 50w or 100w? I'd probably be ok with the "rock clean". Will the 100W head have twice the headroom of the 50W?

HavPT wrote:

ironman28 wrote:

HavPT wrote:I understand that but the problem is that no stores around here in Portugal with Jet City amps. I wish I could try one.

I think I can have the same problem with the JC50h and rp1000 4Cm right?

The 50h and 100h both have the same loop design, so yes the loop problem would be the same. As far as the clean sound on the crunch channel if you are ok with " rock clean" try using an EQ in front when using the crunch channel to help dial it in.

which one? 50w or 100w? I'd probably be ok with the "rock clean". Will the 100W head have twice the headroom of the 50W?

The preamp section of the 50 watt JC and the 100 watt are virtually identical. The 100HDM uses vactrols to switch channels instead of the relays used in the 50h but other than that they have the the same crunch and overdrive channels with the same fx loop. A 100 watt head does not have twice the headroom of a 50 watt head everything else being equal. The SLO design is meant to create distortion in the preamp and run the power amp clean. The problem with the crunch channel being clean is the sensitivity of the preamp which creates distortion even with the crunch volume at relatively low levels. There are some other mods for the crunch channel farther back in this thread to clean it up a little more. One is the mid cut or scoop network used on the Decatone amps which gets you closer to a classic fender style clean sound. The SLO/Jet city preamp will never be able to get that glassy clean sound because of the shared gain stages between the crunch and OD channels. By the time you get the crunch channel clean enough you have neutered the OD high gain sound which is why you buy a SLO .

I think I got it man, thanks for the explanation! Cheers
In the meantime if anyone tried the RP1000 with one of these JCA amps please tell me if it works well.
Thanks

How do you like it with the creamback? I tried my JCA50H with my 4x12 greenback cab, and found it overly harsh / bright. My Marshall head is way better with that cab

I am not sure re; creamback. I do think it is a little stiff (also not fully broken in to be fair). I need more time as I started tinkering with the amp practically right out of the box. I have several speakers and tubes to roll not to mention dicking with the mods. I am not sure how things will settle in. I am awaiting a DPDT's, resistors and caps as well...

Does the JCA100HDM or 50H needs to rebias when changing power tubes? I heard that is auto bias so no need to.

Another thing that is bothering me is that all the people talks about mods for this and mods for that, new kind of valves etc etc, Will this amp sound sucks right out of the box with all stock?

HavPT wrote:Another thing that is bothering me is that all the people talks about mods for this and mods for that, new kind of valves etc etc, Will this amp sound sucks right out of the box with all stock?

I can only speak for the 22h and say no, it sounded great right out of the box, but I bought mine specifically because it is a great modding platform, and I wanted to use its base tones and build off of it by modding it.

HavPT wrote:Does the JCA100HDM or 50H needs to rebias when changing power tubes? I heard that is auto bias so no need to.

Have to bias? No.

But all reports I've seen have been that the amp is set quite cold from the factory, and makes a world of difference. Especially when changing out the stock tubes.

Man I hate that rebias thing, 20 years ago it was change valves and Go! eheheh, mostly on JCM marshall heads.. I need to go maybe 100Km to get the amp biased...

I am actually adding an external bias pot, makes things much easier!

spadearcher wrote:

jb37804 wrote:The Boss NS-2 Noise Suppressor (in an X pattern setup) and the Digitech Hardwire Delay DO NOT work in the JCA50H loop. They suck tone bigtime, sound like its under a pillow.

The Digitech Hardwire Delay (DL-8) works just fine in my JCA100H's loop. In fact that is why I bought it. It's been a while since last time I plugged it in, so I will give it a try just to make sure. I will try it in both channels I cannot remember if I did back in the day.

Yesterday I had the chance to try again my Hardwire DL-8 Delay in the loop of my JCA100H. The signal chain was Les Paul->Input->Send->Hardwire DL-8 Delay->Hardwire RV-7 Reverb->Return

I can confirm that both the DL-8 and the RV-7 work in the loop of the JCA100H without any issues at all. They sound fantastic in fact! No tone suck ando no clipping issues, either engaged or in bypass, and in both channels of the amp. I only tested the delay in digital mode, short setting (500ms), and the reverb in plate mode, but I guess the other modes wouldn't really make any difference regarding tone suck.

Maybe your problem was the Boss NS-2. Did you try the DL-8 alone?

spadearcher wrote:

spadearcher wrote:

jb37804 wrote:The Boss NS-2 Noise Suppressor (in an X pattern setup) and the Digitech Hardwire Delay DO NOT work in the JCA50H loop. They suck tone bigtime, sound like its under a pillow.

The Digitech Hardwire Delay (DL-8) works just fine in my JCA100H's loop. In fact that is why I bought it. It's been a while since last time I plugged it in, so I will give it a try just to make sure. I will try it in both channels I cannot remember if I did back in the day.

Yesterday I had the chance to try again my Hardwire DL-8 Delay in the loop of my JCA100H. The signal chain was Les Paul->Input->Send->Hardwire DL-8 Delay->Hardwire RV-7 Reverb->Return

I can confirm that both the DL-8 and the RV-7 work in the loop of the JCA100H without any issues at all. They sound fantastic in fact! No tone suck ando no clipping issues, either engaged or in bypass, and in both channels of the amp. I only tested the delay in digital mode, short setting (500ms), and the reverb in plate mode, but I guess the other modes wouldn't really make any difference regarding tone suck.

Maybe your problem was the Boss NS-2. Did you try the DL-8 alone?

Thanks man, nice to hear that. Just ordered a JCA100Hdm 3 days ago and have an RV-7 waiting to try

Anyone knows if the Boss delays work too on the JCA FX loop ?

It was good to see the Grimespace's "list of effects found to be compatible with the JCA effects loop" a bigger list.

Got my JCA100HDM + JCA24s+ today, so far I'm impressed with sound, tried only with a telecaster with single coils and loved the sound, I have all the clean sound that I need and more. Pure valve sound really like it out of the box, it sounds very good to me. The cabinet is perfect for me and a good match to the amp.

Tried some pedals in the loop and as known the Hardwire RV-7 works good, tried an old Marshall echohead and sounded ok, no volume loss. Also tried a FAB chorus and sounded good in the loop. Well all of this was with master at 1 I can't go further, my little son is sleeping and I live in a apartment so the test will be in the next band practice.

Well chances are if it sounded good at low volumes it will smoke at band practice volumes.

So far I'm a happy JCA100 owner!

Congrats! Keep us posted.

Hey Guys, I've been gleaning much info off of these pages for the last couple of weeks because I just got a JCA2212C and simply wanted to know more. You all have been a wealth of knowledge, so I had to register just to say thank you!

When I got it, I thought it was a decent amp for the cash, but it wasn't stellar... until I dropped in a new set of JJ EL84s, Completely different beast now! also dropped in a 12AT7 into V2. Tried V1 first, but it made a bigger difference in V2 slot. Going to roll in more pre's when I get a chance, but what a great little amp.
I got it on a thursday afternoon and gigged it the next day. With the original power tubes it was a bit harsh, and crackled a bit, which led me to believe it may have had a bad power tube (or both). But all in all it kept right up with my other guitarists classic 30.

So again, thanks so much for all of the info!

~Lee

Hi All, Just made some mods to my new JCA 22 combo. Those are; new tubes (tung sol V1,2, EH V3, JJ V4, V5- Tungsol el 84), biased, Creamback speaker, Depth mod, choke, slope resistor mod, cathode resistor R49, C2 and C9 from 22n to 10n.
Sounds great however the last mod I want to do is the SLO. I understand the VR 1-2 to 500K pot change and I just need the two other resistor and cap changes. Thanks in advanced for any help

Hi - check the reference on the first page of this thread. I've got a link to Jay's tutorial on the SLO mod there. Should be fairly complete, although I think a few components are ID'd different on the 22. Good luck! SLO is definitely happening for me this summer.

Hi Grimespace, thanks... I've looked that link over countless times and what throws me off is that it indicates that the schematic is for the 50. Kasebrot makes mention of the two resistor and cap changes in the thread at some point but didn't elude to which two they are and I am good at guessing wrong