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[marshallnoise]

I think you can do it, but the thing you really have to be careful with is how much current/voltage/oomph the rotary switch can handle. You are sending outputs from the OT to the rotary switch which will then pass the signal from one of the 3 OT taps to the speaker jack. A simple rotary switch will not do. Look at the back of a Marshall and see what kind of rotary switch THEY use.

[Tortuga]

I have an mod idea . . .

I'm thinking about going from separate output jacks to a rotary impedance selector, and use just 2 output jacks like the Soldanos. There are 5 output jacks currently. The unused output jacks would be used 1) for the rotary selector 2) toggle for DeMartini/scoop mod 3) Effects loop bypass toggle (?). I'm okay with drilling holes on the front chassis for the 2 mini toggles I want like the SLO has, but after that I'd like to use existing holes, and consolidate output jacks at the same time.

What say you?

I like it - have thought it'd be nice to have the output jacks on a switch, but never thought about what I'd do with the rest of the holes. What's the DeMartini mod - same as the normal channel scoop switch that I got from Edge11? And, what will the bypass toggle be for, if not using a footswitch to bypass effects altogether?

How's the Earhart?

[Hipster Salad]

Footswitchable effects on/off would be pretty neat, that could go in place of the effects loop bypass I'm thinking about putting there.

The Earhart...is nice. Still trying to dial it in properly but it sounds great. Tonight I'll give it a run for its money when I A/B with my modded JCA100H

[Jay]

I think you can do it, but the thing you really have to be careful with is how much current/voltage/oomph the rotary switch can handle. You are sending outputs from the OT to the rotary switch which will then pass the signal from one of the 3 OT taps to the speaker jack. A simple rotary switch will not do. Look at the back of a Marshall and see what kind of rotary switch THEY use.

This is what I used on my SLO Clones and other projects

[Jay]

I have an mod idea . . .

I'm thinking about going from separate output jacks to a rotary impedance selector, and use just 2 output jacks like the Soldanos. There are 5 output jacks currently. The unused output jacks would be used 1) for the rotary selector 2) toggle for DeMartini/scoop mod 3) Effects loop bypass toggle (?). I'm okay with drilling holes on the front chassis for the 2 mini toggles I want like the SLO has, but after that I'd like to use existing holes, and consolidate output jacks at the same time.

What say you?

I like it - have thought it'd be nice to have the output jacks on a switch, but never thought about what I'd do with the rest of the holes. What's the DeMartini mod - same as the normal channel scoop switch that I got from Edge11? And, what will the bypass toggle be for, if not using a footswitch to bypass effects altogether?

How's the Earhart?

I got an idea. But......as in typical Jay fashion, it might be too crazy for mere mortals.

First, replace the stock channel switching jack with this or this.

Then, put a pair of 500k pots in two of the unused speaker jacks, hook up some shielded wire in parallel with the crunch channel gain and volume pots with the optos or mosfets as the switch, and voila' a 3 channel JCA.

I know, I know, I still need to get a 50 or 100 and show these things to you guys. lol I'm getting on it.

[Jay]

Footswitchable effects on/off would be pretty neat, that could go in place of the effects loop bypass I'm thinking about putting there.

The Earhart...is nice. Still trying to dial it in properly but it sounds great. Tonight I'll give it a run for its money when I A/B with my modded JCA100H

Well, since the FX loop on these amps are like the SLO loop, I can tell you that they are not transparent, and you will notice a change from switched on to off. Having a hard bypass with a switch might be a better option. Or the two open holes could be used for something like a Solo Boost volume, or a pentode/triode switch, maybe a half-power switch. For the 100H, it could be like the 50w mode on the HDM.

[Jay]

One thing I'd like to work on, is doing custom faceplates or trying to make a template so as we all make mods or changes, (or come up with a community group of mods) we can set a design for a few sets of faceplates based on what mods we have/want with the NAME of the mod AND have the option of different colors/scripts. That way, instead of the black panel with white script, we can have, say, a white panel with black script, or a silver or gold Plexi-type panel.

Also, the panels themselves can be used and drilling templates since most panel makers will drill them out to our specs anyway.

[Jay]

If memory serves Splawn moved away from Heyboer for business reasons and is now sourcing transformers out of a new supplier from Texas. I'll look inside my 2012 Quick Rod and see if I can ID it.

Actually, I happened to stumble on why Splawn is using other Transformers. I'm not sure if he is stopping the use of the Heyboers or he is using an additional supplier. Apparently Heyboer cannot keep up with demand, so Scott is calling on Classictone to do some units also. Another reason he is going with some Classictone iron, is that some of the Vertical-mount Heyboers have been tweaked and shifted one they are shipped in an amp IF the amp has been dropped or abused. Classictone is making Laydown style transformers which hold up a lot better with heavy abuse. Either way, it seems most tone junkies sing the praises of Classictone or Heyboer.

[Jase01]

Hi, can someone please tell me the components to switch out for the "more gain in the crunch channel" mod on the 22h?
Also, there was talk on the HC forum of having switchable resister values on the nfb resistor, but i can't log in over there, somethings screwed up.......
"If you want to make things switchable, try this with the nfb resistor. 8 or 10k more and you will get a much tighter sound."
Anyone know how to make this happen? Diagram?
Cheers..

[Jay]

Well, if you want a little more gain, try putting a 1uF cap in parallel with R4. You can also put it on a switch for when you don't want the extra boost. A lot of the 20H guys do that and get really good results. If you need more after that, we can do some more stuff.

For the NFB resistor switch, was that just ther XL mod for the Hotrods and Lead60?

[Jase01]

Well, if you want a little more gain, try putting a 1uF cap in parallel with R4. You can also put it on a switch for when you don't want the extra boost. A lot of the 20H guys do that and get really good results. If you need more after that, we can do some more stuff.

For the NFB resistor switch, was that just ther XL mod for the Hotrods and Lead60?

Thanks I'll try that. Do I use a dpdt switch? And do I just solder the cap to the switch and run wires from R4 to the switch? ( could you please do a simple diagram?)

Not sure about the NFB mod, it was suggested as an alternative to a switchable slope mod, but I was thinking of doing both.

Oh yeah, whats the best type of capacitor to use?

[Hipster Salad]

Footswitchable effects on/off would be pretty neat, that could go in place of the effects loop bypass I'm thinking about putting there.

The Earhart...is nice. Still trying to dial it in properly but it sounds great. Tonight I'll give it a run for its money when I A/B with my modded JCA100H

Well, since the FX loop on these amps are like the SLO loop, I can tell you that they are not transparent, and you will notice a change from switched on to off. Having a hard bypass with a switch might be a better option. Or the two open holes could be used for something like a Solo Boost volume, or a pentode/triode switch, maybe a half-power switch. For the 100H, it could be like the 50w mode on the HDM.

Hard bypass with a switch is what I meant, but didn't clarify.

[Jay]

Well, if you want a little more gain, try putting a 1uF cap in parallel with R4. You can also put it on a switch for when you don't want the extra boost. A lot of the 20H guys do that and get really good results. If you need more after that, we can do some more stuff.

For the NFB resistor switch, was that just ther XL mod for the Hotrods and Lead60?

Thanks I'll try that. Do I use a dpdt switch? And do I just solder the cap to the switch and run wires from R4 to the switch? ( could you please do a simple diagram?)

Not sure about the NFB mod, it was suggested as an alternative to a switchable slope mod, but I was thinking of doing both.

Oh yeah, whats the best type of capacitor to use?

I'll try and do a simple diagram. Give me some time to find/make a decent illustration though. lol

A 2 position DPDT will work. As for caps, you can use a 63v or 100v cap. I'm going to use the Vishay/Roederstein MKT1813 for my next build, or you can try the Vishay MKT368, which is very comparable to what the SLO uses. A good "poly" type will be your best bet.

[Jay]

Footswitchable effects on/off would be pretty neat, that could go in place of the effects loop bypass I'm thinking about putting there.

The Earhart...is nice. Still trying to dial it in properly but it sounds great. Tonight I'll give it a run for its money when I A/B with my modded JCA100H

Well, since the FX loop on these amps are like the SLO loop, I can tell you that they are not transparent, and you will notice a change from switched on to off. Having a hard bypass with a switch might be a better option. Or the two open holes could be used for something like a Solo Boost volume, or a pentode/triode switch, maybe a half-power switch. For the 100H, it could be like the 50w mode on the HDM.

Hard bypass with a switch is what I meant, but didn't clarify.

Gotcha! A few of the SLO crowd have done it. A lot of players actually like it better without the loop.

[Jay]

Well, if you want a little more gain, try putting a 1uF cap in parallel with R4. You can also put it on a switch for when you don't want the extra boost. A lot of the 20H guys do that and get really good results. If you need more after that, we can do some more stuff.

For the NFB resistor switch, was that just ther XL mod for the Hotrods and Lead60?

Thanks I'll try that. Do I use a dpdt switch? And do I just solder the cap to the switch and run wires from R4 to the switch? ( could you please do a simple diagram?)

Not sure about the NFB mod, it was suggested as an alternative to a switchable slope mod, but I was thinking of doing both.

Oh yeah, whats the best type of capacitor to use?

I'll try and do a simple diagram. Give me some time to find/make a decent illustration though. lol

A 2 position DPDT will work. As for caps, you can use a 63v or 100v cap. I'm going to use the Vishay/Roederstein MKT1813 for my next build, or you can try the Vishay MKT368, which is very comparable to what the SLO uses. A good "poly" type will be your best bet.

Okay, try this. I hope this diagram works for you. It's my first time doing an illustration. Don't laugh. You want the capacitor to have a voltage reference, or you will get popping when you switch it on or off.

[Jay]

On a side note, I found some of my leftover SLO clone boards, so instead of doing a 20H build, I think I may end up doing a 22H instead.

[Jase01]

Well, if you want a little more gain, try putting a 1uF cap in parallel with R4. You can also put it on a switch for when you don't want the extra boost. A lot of the 20H guys do that and get really good results. If you need more after that, we can do some more stuff.

For the NFB resistor switch, was that just ther XL mod for the Hotrods and Lead60?

Thanks I'll try that. Do I use a dpdt switch? And do I just solder the cap to the switch and run wires from R4 to the switch? ( could you please do a simple diagram?)

Not sure about the NFB mod, it was suggested as an alternative to a switchable slope mod, but I was thinking of doing both.

Oh yeah, whats the best type of capacitor to use?

I'll try and do a simple diagram. Give me some time to find/make a decent illustration though. lol

A 2 position DPDT will work. As for caps, you can use a 63v or 100v cap. I'm going to use the Vishay/Roederstein MKT1813 for my next build, or you can try the Vishay MKT368, which is very comparable to what the SLO uses. A good "poly" type will be your best bet.

Okay, try this. I hope this diagram works for you. It's my first time doing an illustration. Don't laugh. You want the capacitor to have a voltage reference, or you will get popping when you switch it on or off.

Cheers for that!! Is it pin 3 or 8 for the cathode?

[Jase01]

Just tried to bias my new "Matched" TAD str EL84's from the TubeStore.com and one reads 22ma and the other is 18ma? WTF?
I did it using the method in the video on the last page, have I fucked up or are these tubes haywire?


Put my JJ's back in and there's less than 1 difference... Looks like they're staying there.

[edge11]

Oh snap!
22h/50h/100h mod thread!
I'll bring the 20h thread here soon too!
viewtopic.php?f=5&t=3840

[Jase01]

Well, if you want a little more gain, try putting a 1uF cap in parallel with R4. You can also put it on a switch for when you don't want the extra boost. A lot of the 20H guys do that and get really good results. If you need more after that, we can do some more stuff.

For the NFB resistor switch, was that just ther XL mod for the Hotrods and Lead60?

Thanks I'll try that. Do I use a dpdt switch? And do I just solder the cap to the switch and run wires from R4 to the switch? ( could you please do a simple diagram?)

Not sure about the NFB mod, it was suggested as an alternative to a switchable slope mod, but I was thinking of doing both.

Oh yeah, whats the best type of capacitor to use?

I'll try and do a simple diagram. Give me some time to find/make a decent illustration though. lol

A 2 position DPDT will work. As for caps, you can use a 63v or 100v cap. I'm going to use the Vishay/Roederstein MKT1813 for my next build, or you can try the Vishay MKT368, which is very comparable to what the SLO uses. A good "poly" type will be your best bet.

Okay, try this. I hope this diagram works for you. It's my first time doing an illustration. Don't laugh. You want the capacitor to have a voltage reference, or you will get popping when you switch it on or off.

Cheers for that!! Is it pin 3 or 8 for the cathode?

Whats the value of the resistor?

[edge11]

Hi to all!
First steps here...
Happy to join the Jet City Lounge

Hiya, sevenmusic, welcome to the happiest place on (virtual) earth! Are you the same guy from the HCAF? If so, thanks so much for posting the HDM schematic over there! Assuming so, do you have an HDM, and would you be willing to take some gut shots of your amp for us? I'd very much like to see the labels on the transformers, inside wiring for the 50/100 switch, channel LED, and depth knob, and some shots of the PCB and back panel wiring as well.

Hi Grimespace,

I'm the same guy from HCAF
Unfortunately, i don't have the HDM but a JCA 100H...

mind if i put the hdm schematic the mod threads in both sites?

[sevenmusic]

Hi to all!
First steps here...
Happy to join the Jet City Lounge

Hiya, sevenmusic, welcome to the happiest place on (virtual) earth! Are you the same guy from the HCAF? If so, thanks so much for posting the HDM schematic over there! Assuming so, do you have an HDM, and would you be willing to take some gut shots of your amp for us? I'd very much like to see the labels on the transformers, inside wiring for the 50/100 switch, channel LED, and depth knob, and some shots of the PCB and back panel wiring as well.

Hi Grimespace,

I'm the same guy from HCAF
Unfortunately, i don't have the HDM but a JCA 100H...

mind if i put the hdm schematic the mod threads in both sites?

Hi Edge 11,

Quite the contrary, it seems to me a great idea...

[Jay]

Hi to all!
First steps here...
Happy to join the Jet City Lounge

Hiya, sevenmusic, welcome to the happiest place on (virtual) earth! Are you the same guy from the HCAF? If so, thanks so much for posting the HDM schematic over there! Assuming so, do you have an HDM, and would you be willing to take some gut shots of your amp for us? I'd very much like to see the labels on the transformers, inside wiring for the 50/100 switch, channel LED, and depth knob, and some shots of the PCB and back panel wiring as well.

Hi Grimespace,

I'm the same guy from HCAF
Unfortunately, i don't have the HDM but a JCA 100H...

mind if i put the hdm schematic the mod threads in both sites?

I posted a link to the Scheme. We have started doing individual threads in the DIY section for mods/documentation and stuff. Welcome back!

Is that captain tube in your avatar?

[Jay]

Well, if you want a little more gain, try putting a 1uF cap in parallel with R4. You can also put it on a switch for when you don't want the extra boost. A lot of the 20H guys do that and get really good results. If you need more after that, we can do some more stuff.

For the NFB resistor switch, was that just ther XL mod for the Hotrods and Lead60?

Thanks I'll try that. Do I use a dpdt switch? And do I just solder the cap to the switch and run wires from R4 to the switch? ( could you please do a simple diagram?)

Not sure about the NFB mod, it was suggested as an alternative to a switchable slope mod, but I was thinking of doing both.

Oh yeah, whats the best type of capacitor to use?

I'll try and do a simple diagram. Give me some time to find/make a decent illustration though. lol

A 2 position DPDT will work. As for caps, you can use a 63v or 100v cap. I'm going to use the Vishay/Roederstein MKT1813 for my next build, or you can try the Vishay MKT368, which is very comparable to what the SLO uses. A good "poly" type will be your best bet.

Okay, try this. I hope this diagram works for you. It's my first time doing an illustration. Don't laugh. You want the capacitor to have a voltage reference, or you will get popping when you switch it on or off.

Cheers for that!! Is it pin 3 or 8 for the cathode?

Whats the value of the resistor?

R4 should be a 2.2k resistor.

[Meelocheck]

Just tried to bias my new "Matched" TAD str EL84's from the TubeStore.com and one reads 22ma and the other is 18ma? WTF?
I did it using the method in the video on the last page, have I fucked up or are these tubes haywire?


Put my JJ's back in and there's less than 1 difference... Looks like they're staying there.

I am guessing those new tubes aren't as matched as they claim. My stock tubes had a difference of 8mA...One would read 20mA while the other just a hair above 12mA. The new tubes I bought are Mesas (tested and matched) and they are less than 1mA apart in readings (20mA and 19.2mA)...If it is the video I think it is I am the one who posted it on the last page. I am using the same method and Jay had confirmed it is indeed the correct way to bias these amps using a DMM. If your new tubes are off 4mA then I would suggest trying to return them for another set or trying a different brand all together. Why did you try to replace the JJ's anyway? Not the sound you were looking for?

Jay, I will try to get in touch with my buddy today and get that contact info for you. Sorry - been out of town for about a week.