SV20c questions

[Essexmark]

Hello all
Further to my previous questions around what studio amp I've decided that the Studio Vintage range is best suited for me
Im thinking potentially the combo will be best suited to me at the moment so I wonder if I can ask some questions please on the SV20c. Quick background. Player in the 90s through a JTM600 head and 4x10 cab, but for at least the last 15 years I've not played at all due to family and work. JTM went many years ago. Picked guitar back up this year, having lessons and starting to build a little collection of amps and guitars to play at home and to take me into retirement in 6 or 7 years time. I hope in the future to maybe be get into friend's small band but we'll see.
So the SV combo and forgive me please if these seem like stupid questions to some of you
1) using an Attenuator. I understand these go between amp and speaker. Is it easy to do this in the SV combo?
2) if I add the 1x12 SV extension cab in the future does connecting this to the SV combo disengage the internal combo speaker or in effect give you a 1x10 and 1x12 speaker configuration?
3) if I do use extension cab but still need to use an Attenuator (and subject to the internal speaker still in use with the extension cab) can the Attenuator go between the Combo and extension cab or does it have to still go between the amp and the internal speaker

Apologies again to those more experienced in these matters if these are dumb questions but they are all genuine

Thanks all
Mark

Mark

 

[Mitchell Pearrow]

Be patient more knowledgeable members will be along to help with your questions. I don’t use an attenuator, so I am not much help here.

Cheers

 

[Mastershon]

I use a Carls Custom Guitars power soak attenuator with my SV20C. Fits perfectly right in the back, sounds fantastic at all volume levels. I love it!

 

[fitz288]

Hello all
Further to my previous questions around what studio amp I've decided that the Studio Vintage range is best suited for me
Im thinking potentially the combo will be best suited to me at the moment so I wonder if I can ask some questions please on the SV20c. Quick background. Player in the 90s through a JTM600 head and 4x10 cab, but for at least the last 15 years I've not played at all due to family and work. JTM went many years ago. Picked guitar back up this year, having lessons and starting to build a little collection of amps and guitars to play at home and to take me into retirement in 6 or 7 years time. I hope in the future to maybe be get into friend's small band but we'll see.
So the SV combo and forgive me please if these seem like stupid questions to some of you
1) using an Attenuator. I understand these go between amp and speaker. Is it easy to do this in the SV combo?
2) if I add the 1x12 SV extension cab in the future does connecting this to the SV combo disengage the internal combo speaker or in effect give you a 1x10 and 1x12 speaker configuration?
3) if I do use extension cab but still need to use an Attenuator (and subject to the internal speaker still in use with the extension cab) can the Attenuator go between the Combo and extension cab or does it have to still go between the amp and the internal speaker

Apologies again to those more experienced in these matters if these are dumb questions but they are all genuine

Thanks all
Mark

Mark

I don't have this amp, but can answer these questions.
1) You may need an extension speaker cable to go from the attenuator to the speaker, and another speaker cable from amp to attenuator.
2) (removed incorrect info) - not sure if the SV112 is the same impedance as the internal VT jr - they would need to match - (more wrong stuff was here)
3) depending on the attenuator output, you may need a cab merger to get both speaker to one cable.
4) no offense to @Mastershon , Carl's Speaker Soak suck (tone).

 

[Chris-in-LA]

Forget the attenuator, get the SC20 and you won’t need one.

 

[Mastershon]

I don't have this amp, but can answer these questions.
1) You may need an extension speaker cable to go from the attenuator to the speaker, and another speaker cable from amp to attenuator.
2) the amp has 2 speaker jacks (parallel, I assume) and a selectable 4-8-16 ohm output - not sure if the SV112 is the same impedance as the internal VT jr - they would need to match - and you'll need to change the selector when you use / don't use the extension cab.
3) depending on the attenuator output, you may need a cab merger to get both speaker to one cable.
4) no offense to @Mastershon , Carl's Speaker Soak suck (tone).

The attenuator does alter the tone, but it’s really only noticeable when reduced to very low levels. Even at mouse fart levels it still sounds great. No extension cab needed just 1 short speaker cable from amp to attenuator IN, then the existing speaker cable plugs into the attenuator OUT.

 

[fitz288]

Another option, that some here say works well, is the JHS Little Black Box volume knob device in the loop.
It's NOT an attenuator, but can accomplish a similar function.

 

[junk notes]

Hello all
Further to my previous questions around what studio amp I've decided that the Studio Vintage range is best suited for me
Im thinking potentially the combo will be best suited to me at the moment so I wonder if I can ask some questions please on the SV20c. Quick background. Player in the 90s through a JTM600 head and 4x10 cab, but for at least the last 15 years I've not played at all due to family and work. JTM went many years ago. Picked guitar back up this year, having lessons and starting to build a little collection of amps and guitars to play at home and to take me into retirement in 6 or 7 years time. I hope in the future to maybe be get into friend's small band but we'll see.
So the SV combo and forgive me please if these seem like stupid questions to some of you
1) using an Attenuator. I understand these go between amp and speaker. Is it easy to do this in the SV combo?
2) if I add the 1x12 SV extension cab in the future does connecting this to the SV combo disengage the internal combo speaker or in effect give you a 1x10 and 1x12 speaker configuration?
3) if I do use extension cab but still need to use an Attenuator (and subject to the internal speaker still in use with the extension cab) can the Attenuator go between the Combo and extension cab or does it have to still go between the amp and the internal speaker

Apologies again to those more experienced in these matters if these are dumb questions but they are all genuine

Thanks all
Mark

Mark

Glad you are back playing and getting back to the GAS. You will be ahead of the curve and doing just fine being in that band down the road.

Is the JHS similar to the soak; I wonder if you could use that soak like the JHS little black amp box in the loop then IDK?

The usual suspects in attenuators have more than one speaker out so using and extension cab will be tricky with the soak - designed cosmetically like a pedal, with one in and one out. You would also have to check load ratings. (edit: If there is one, the extension speaker might have a parallel jack that would help.)

..and your questions are far from stupid, just having your concerns in making good choices. GL
get a real attenuator since you are getting an SV. plenty to choose from in various price ranges.

 

[Gene Ballzz]

@fitz288 , @Essexmark & All,

The SV20C, as with all the Studio series combos and heads does NOT have a pair of parallel jacks and a selector. They instead have five speaker output jacks, that are labeled: 1 x 16Ω, 1 x 8Ω/2 x 16Ω & 1 x 4Ω/2 x 8Ω.

Properly matching the impedance is critical. The internal speaker is simply plugged out of the 1 x 16Ω jack and can be "unplugged" to use just an extension speaker or attenuator> internal speaker or> extension speaker. In the case of using an attenuator and the internal speaker, simply unplug the internal speaker from it's jack, plug the attenuator input out of the proper impedance jack of the amp and plug the speaker plug out of the output of the attenuator. If the cable on the speaker is too short, just get a device like the one below and use another speaker cable to extend the length.

It should be remembered to always use a speaker cable and NOT a shielded instrument cable for connecting speakers! Although the plugs are the same, the wire and it's current capabilities are not.

When it comes to attenuators, they are certainly not all created equal. Some compromize tone more than others. The best "passive" (requires no power supply) unit is the @JohnH unit (linked below) designed by our very own genius JohnH. The only downside is that you need to build it yourself, or have someone do it for you! It is by far, the best and least tone sucking design of all passive speaker attenuators! It should be noted that many who don't actually use attenuators seem to think they are all the same, but nothing could be further from the truth!

Simple Attenuators - Design And Testing

Summary: September 2019 This thread started with a few resistors to make a simple attenuator for valve amps, and then developed into multistage resistive and reactive designs. The latest designs work much better than I’d expected and have been built and tested by others. April 2020: After...

www.marshallforum.com

All that said, the SV20, both C & H, are some of the best products that Marshall has offered in many years! A quick question, what part of the world are you located in? The answer to that may have a great impact on what help and advice may pertinent to you!

Enjoy,
Gene

 

[fitz288]

The SV20C, as with all the Studio series combos and heads does NOT have a pair of parallel jacks and a selector. They instead have five speaker output jacks, that are labeled: 1 x 16Ω, 1 x 8Ω/2 x 16Ω & 1 x 4Ω/2 x 8Ω.

I was thinking the same thing, but saw this on the Marshall site...

I apologize if my statements are not correct - as i said, I don't have this amp.

 

[Essexmark]

@fitz288 , @Essexmark & All,

The SV20C, as with all the Studio series combos and heads does NOT have a pair of parallel jacks and a selector. They instead have five speaker output jacks, that are labeled: 1 x 16Ω, 1 x 8Ω/2 x 16Ω & 1 x 4Ω/2 x 8Ω.

Properly matching the impedance is critical. The internal speaker is simply plugged out of the 1 x 16Ω jack and can be "unplugged" to use just an extension speaker or attenuator> internal speaker or> extension speaker. In the case of using an attenuator and the internal speaker, simply unplug the internal speaker from it's jack, plug the attenuator input out of the proper impedance jack of the amp and plug the speaker plug out of the output of the attenuator. If the cable on the speaker is too short, just get a device like the one below and use another speaker cable to extend the length.

It should be remembered to always use a speaker cable and NOT a shielded instrument cable for connecting speakers! Although the plugs are the same, the wire and it's current capabilities are not.

When it comes to attenuators, they are certainly not all created equal. Some compromize tone more than others. The best "passive" (requires no power supply) unit is the @JohnH unit (link below) designed by our very own gwenius JohnH. The only downside is that you need to build it yourself, or have someone do it for you! It is by far, the best and least tone sucking of all pssive speaker attenuators!

Simple Attenuators - Design And Testing

Summary: September 2019 This thread started with a few resistors to make a simple attenuator for valve amps, and then developed into multistage resistive and reactive designs. The latest designs work much better than I’d expected and have been built and tested by others. April 2020: After...

www.marshallforum.com

All that said, the SV20, both C & H, are some of the best products that Marshall has offered in many years! A quick question, what part of the world are you located in? The answer to that may have a great impact on what advice may pertinent to you!

Enjoy,
Gene

Hi Gene
I'm UK based, in Essex mate
Thanks for your reply
Mark

 

[paul-e-mann]

Hello all
Further to my previous questions around what studio amp I've decided that the Studio Vintage range is best suited for me
Im thinking potentially the combo will be best suited to me at the moment so I wonder if I can ask some questions please on the SV20c. Quick background. Player in the 90s through a JTM600 head and 4x10 cab, but for at least the last 15 years I've not played at all due to family and work. JTM went many years ago. Picked guitar back up this year, having lessons and starting to build a little collection of amps and guitars to play at home and to take me into retirement in 6 or 7 years time. I hope in the future to maybe be get into friend's small band but we'll see.
So the SV combo and forgive me please if these seem like stupid questions to some of you
1) using an Attenuator. I understand these go between amp and speaker. Is it easy to do this in the SV combo?
2) if I add the 1x12 SV extension cab in the future does connecting this to the SV combo disengage the internal combo speaker or in effect give you a 1x10 and 1x12 speaker configuration?
3) if I do use extension cab but still need to use an Attenuator (and subject to the internal speaker still in use with the extension cab) can the Attenuator go between the Combo and extension cab or does it have to still go between the amp and the internal speaker

Apologies again to those more experienced in these matters if these are dumb questions but they are all genuine

Thanks all
Mark

Mark

I would think just using a pair of speaker cable splitters to go between the amp-attenuator-speaker would do the trick. Make sure to get the same ohm speaker for your cab as the combo. Or maybe to simplify your setup just get a 2x12 cab, disconnect the combo internal speaker and connect directly to the cab. You'd definitely get a better sound disconnecting the 10" speaker and just go through a pair of 12" speakers.

 

[Gene Ballzz]

I was thinking the same thing, but saw this on the Marshall site...
View attachment 110247
I apologize if my statements are not correct - as i said, I don't have this amp.

@fitz288 ,
The five jack configuration can indeed be a bit confusing. Especially when you factor in that some of the designers from Marshall (one or two of them frequent this site) claim that you can even use mismatched impedance cabinets with this configuration, although it only works for an 8Ω load and a 16Ω load. You plug the 16Ω speaker from the 8Ω out and the 8Ω speaker from the 4Ω out, for a "half" load on each. Though the experts may say its "OK" I'm still a bit leary and prefer to have properly matched speakers and amp output impedances! You then get into sensitivity differences between different speakers as well as many other issues the live down that rabbit hole!

You're a good guy and I certainly didn't mean to call you out, but misinformation shared is rarely a good thing, especially when some of that "misinformation" is fostered by sloppy product support from the manufacturer itself, as evidenced by the exerpt you shared! It does however appear that Marshall has by now corrected the error at their website!

And FWIW, the SV20 C & H are exactly the same amps , in different boxes, with a reversed/upside down faceplate and one has a speaker, while the other does not!

Happy Marshallin'
Gene

 

[fitz288]

It does however appear that Marshall has by now corrected the error at their website!

Correct in the manual.

Website still shows the screen clip I posted earlier.
Unless I'm getting a different Marshall website?

SV20C

The power of a Plexi in a new portable style. Now the legendary sound of the 1959SLP is yours for the taking, packaged in a 20W combo that you can enjoy at home or in the studio. It’s got the same vintage tones you know and love, just redesigned for the modern player.

marshall.com

 

[Gene Ballzz]

Correct in the manual.
View attachment 110249
Website still shows the screen clip I posted earlier.
Unless I'm getting a different Marshall website?

SV20C

The power of a Plexi in a new portable style. Now the legendary sound of the 1959SLP is yours for the taking, packaged in a 20W combo that you can enjoy at home or in the studio. It’s got the same vintage tones you know and love, just redesigned for the modern player.

marshall.com

Yeah, I searched a little bit for the "error" but didn't find it! Maybe it's on a single page of ad copy that the editors may have missed? A link would be nice and maybe one of us should point it out to Marshall?

Thanks Again,
Gene

 

[donwagar]

I have the SV20C with a JohnH attenuator. I don't have a need for an extension cab, you might find the same.

Someone with more knowledge than me can maybe address this.

I just use the internal 10", a 16 ohm speaker, so I built a 16 ohm attenuator. Using the adaptor Gene shows above, easy to use.

But, if you are using the internal 16 ohm speaker, plus an external 16 ohm speaker (the attenuator should have two speaker outs), now your speaker impedance is 8 ohms. As I understand it, the most important match is between the amp and the attenuator, I don't know if it's okay to mismatch the attenuator to the speakers. If not, you are going to need a 16 ohm attenuator to use just the internal speaker, and an 8 ohm attenuator for when you are using two speakers, or find an attenuator that will switch between 8 and 16 ohms.

 

[Gene Ballzz]

Wait, I did find the error on the SV20C "TECHNICAL SPECIFICATION" page! The error does not show up on the the tech spec page for any other Studio model, though!
Thanks,
Gene

 

[Gene Ballzz]

I have the SV20C with a JohnH attenuator. I don't have a need for an extension cab, you might find the same.

Someone with more knowledge than me can maybe address this.

I just use the internal 10", a 16 ohm speaker, so I built a 16 ohm attenuator. Using the adaptor Gene shows above, easy to use.

But, if you are using the internal 16 ohm speaker, plus an external 16 ohm speaker (the attenuator should have two speaker outs), now your speaker impedance is 8 ohms. As I understand it, the most important match is between the amp and the attenuator, I don't know if it's okay to mismatch the attenuator to the speakers. If not, you are going to need a 16 ohm attenuator to use just the internal speaker, and an 8 ohm attenuator for when you are using two speakers, or find an attenuator that will switch between 8 and 16 ohms.

It is in fact totally "safe" to use an 8Ω speaker load with the JohnH, 16Ω unit, but there will be a slight loss of 1-2 db in a portion of the upper mid range! That area of the frequency spectrum is absolutely crucial for my style of "Screechin' & Squawkin'" so I built an extra 8 ohm unit, for my 8 ohm, 4x10, 1965B cabinet! The difference/loss is pretty subtle, but I hear it!

And FWIW, even though these attenuators are not commercially available for purchase, "I know a guy" willing to build one. Anyone wanting one, but lacking the means to build one should contact me privately for info!

Still Crankin'
Gene

 

[Coachmoe]

I am not sure what you want to use an attenuator for. The SV 20C and H variants have a HIGH / LOW power switch. At how, I use the low side and it is a very reasonable volume for bedroom or basement. For live shows, I can go high power and let the amp breath. As we always mike the amps, It has plenty of volume and the guys on stage don't complain.

 

[Gene Ballzz]

I am not sure what you want to use an attenuator for. The SV 20C and H variants have a HIGH / LOW power switch. At how, I use the low side and it is a very reasonable volume for bedroom or basement. For live shows, I can go high power and let the amp breath. As we always mike the amps, It has plenty of volume and the guys on stage don't complain.

I've found that with the amp fairly cranked up, the power reduction at LOW only drops about 3-4dbs in overall volume and is still quite loud. The default fiirst stage of my @JohnH attenuators is -7db and the low power switch of my SV20 drops the volume considerably less than that! FWIW though, that LOW power mode does not seem to mess much with the tone, other than reduced air movement from the speaker(s). For general band use, I use the Full power setting , with -7db attenuation, which is just a tad quieter than LOW power, by itself!
Just My $.02,
Gene