The ultra-low switch on an SVT

[logdrum]

I had an SVT CL at one point but I never really used it and sold it eventually. I also never had a an 810. The most cab I had was my Mesa 1X15 and a 210 or 2 1X12 Aguilars and those cabs just got too boomy when I had the ultra low switch engaged even if I cut the bass. I was subbing for a reggae gig they had an 8X10 and I think that's the only cab that makes sense to have the ultra low engaged. The BL asked me to engage it and it sounded tight. I think it's how the 810 Fridge is constructed and the response of those drivers.

I now have an Ampeg pedal and the ultra low switch is still useless with my cab setup unless you want mud. Anyway, not news for you folks but the 8X10 is an integral part. I would say that unless you got an 8X10, do not bother getting an SVT.

Anyway here is the block diagram of the SVT and it is interesting how the EQ flow is set. The mid shaping is last. I wonder what the experts can tell about this. So different from the Mesa 400+ which I am used to (it is quirky because the treble affects the bass and then there is the graphic EQ ).

 

[callofcthulhu]

If you cut back the added low end using the bass knob it’s just a 500hz mid scoop. You can then use the mid knob to add back more musical/cutting/useful frequencies as appropriate.

That’s the way I use mine, anyway.

 

[inflatablefilth]

I suppose it depends what kind of sound you want, but I have an SVT-CL and an 810e - and play rock with a P bass and a pick - and there's more than enough low end without engaging the ultra low switch. Having the switch in seems a good way to not really be heard in the mix (tho certainly felt)

 

[logdrum]

If you cut back the added low end using the bass knob it’s just a 500hz mid scoop. You can then use the mid knob to add back more musical/cutting/useful frequencies as appropriate.

That’s the way I use mine, anyway.

I get that but only with the 810 am I able to make it useful without cutting the bass. It just created this punch that was not overwhelming. The mesa on the other hand had the bass boost on the end and was more quirky. There is a reason why the SVT/810 combo works.

I was wondering if the bass/treble on the SVT is a Baxandall

 

[logdrum]

I suppose it depends what kind of sound you want, but I have an SVT-CL and an 810e - and play rock with a P bass and a pick - and there's more than enough low end without engaging the ultra low switch. Having the switch in seems a good way to not really be heard in the mix (tho certainly felt)

Yeah - But of all cab choices, the ultra low seems to be useful with the Ampeg 810 only. It was so effective with a jazz bass with more bridge pickup in that reggae band . I was sent a recording of that gig by the BL lately and I really like how the bass sounded. I remembered how I felt it as well. Anyway, I've seen Avishai Cohen - an upright bass player in a jazz trio (he sings too ) and he uses an SVT with an 810. I love how he sounds with it. His backline rider specs an SVT and 810. I do not think he engages the ultra low. It's not for loud rock bands only.

Anyway - the SVT architecture has not changed for ~50 years now. I am just reminiscing I guess on this cold frigid evening/

 

[beans-on-toast]

The bass and treble are part of a James tone stage, the circuit works as a unit. The mid is typically next. It takes the high and low end shaping and acts on the mid frequencies between them.

The ultra-low switch, when engaged, notches out -20dB @600Hz. This gives you the illusion that there is more bass.

 

[Wasnex]

@logdrum

Here's a low-rez chart that shows what the Ultra-Low switch does in the vintage circuit. The deep mid notch is the Ultra-Low switch.

The magazine article this is from says, "a notch filter is provided at about 500-600hz." The 1977 Service Manual say "-20dB at 600hz," but as you can see, it has a flat null that appears to start just below 500hz and runs up to almost 600hz.

Ref: Totally transparent combo bass amp?

If you squint just right you can read the article.

My appraisal of the switch is it provides instant bedroom tone, except it's hyped way too much. It sounds sort of "HiFi" through an 810 when you play by yourself, but it's a recipe to get lost in the mix when you are playing with a band. Also IMHO, if you want to use this sort of tone, you need way more power than a 300W SVT can provide.

So in short, I think the switch is just too extreme and I find it totally useless even with an 810. I also find the bright switch useless.

The Mid-Selector has value. I generally prefer the 800hz position and my second choice is 250hz. I generally don't care for the 3khz position.

I don't agree with this statement, "...unless you got an 8X10, do not bother getting an SVT." I own a 69 SVT and an 87 Skunk SVT and I think they sound fabulous through my Genz Benz 1288Ts and they also sound fabulous through my home brew Electro Voice TL405s loaded with EVM18Bs.

The first bass rig I ever bought was a brand new MTI era SVT and 810. I consider that purchase a huge mistake. I had it special ordered based on the SVT's stellar reputation. When the rig came in, the music store let me play it and IMHO it sounded so bad that I thought something was wrong with it. Since then I have learned that is just the way SVTs sound through an 810. The key is I am not a fan of the way Ampeg 810s sound.

Since the rig was special ordered I had to pay it off. I took it home and wound up running it as part of a huge biamp rig. Sounded great, weight a ton, but at least I was young, strong, and inexperienced . All part of growing up, and I definitely learned something in the process--try before you make a down payment on a super expensive rig.

Lot's a of people love the 810, so I don't really intend to infer anything other that it's not my sound. If you love 810Es, by all means INJOY! Just don't try to ram one down my throat, because I have a well researched position and very strong opinion on the cab...to be succinct .

 

[bobyoung53]

I had an SVT CL at one point but I never really used it and sold it eventually. I also never had a an 810. The most cab I had was my Mesa 1X15 and a 210 or 2 1X12 Aguilars and those cabs just got too boomy when I had the ultra low switch engaged even if I cut the bass. I was subbing for a reggae gig they had an 8X10 and I think that's the only cab that makes sense to have the ultra low engaged. The BL asked me to engage it and it sounded tight. I think it's how the 810 Fridge is constructed and the response of those drivers.

I now have an Ampeg pedal and the ultra low switch is still useless with my cab setup unless you want mud. Anyway, not news for you folks but the 8X10 is an integral part. I would say that unless you got an 8X10, do not bother getting an SVT.

Anyway here is the block diagram of the SVT and it is interesting how the EQ flow is set. The mid shaping is last. I wonder what the experts can tell about this. So different from the Mesa 400+ which I am used to (it is quirky because the treble affects the bass and then there is the graphic EQ ).

View attachment 4168117

As others said it doesn't boost bass, it cuts mids. You can use the ultra lo and add mids with the mid switch set at 220 and turn up the mid pot a little, I'll do that sometimes, different rooms are different and take different settings. I will also sometimes use ultra lo when playing an SVT head through Ampeg B-15T single 4 ohm 15" cabs. The pots on an ampeg go a long way, just learn to be judicious with how much you turn them either way. A little goes a long way. That being said I don't use it that often but it's nice to have especially in a studio.

 

[metron]

I had a few SVTs and my thoughts on the ultra low are ignore it because it sounds awful. Its like contour on an RB amp... not an option.