Output transformer for SVT-CL that doesn't limit low frequencies

[EricssonB]

As someone who runs a steep HPF at 27.2Hz to preserve the efficiency of my amps/cabs and reduce the mud (as well as being too caffeinated on a night shift told hold back), how much musical information do you get from a bass guitar fundamental of 30Hz?

At that range, you can feel it, but it doesn't always discern itself as musical information, and is liable to add mud depending on the situation/venue.

I really don't mean to open an unwanted can of worms. Just wondering.

 

[Slevage]

As someone who runs a steep HPF at 27.2Hz to preserve the efficiency of my amps/cabs and reduce the mud (as well as being too caffeinated on a night shift told hold back), how much musical information do you get from a bass guitar fundamental of 30Hz?

At that range, you can feel it, but it doesn't always discern itself as musical information, and is liable to add mud depending on the situation/venue.

I really don't mean to open an unwanted can of worms. Just wondering.

Also, I believe inductors let all of the low stuff through---- capacitors block the low stuff. I used to put a cap in series with the tops of my 3way active PA in case someone moved the x over point at the rack.

 

[Chris 'Wighat' Jordan]

As someone who runs a steep HPF at 27.2Hz to preserve the efficiency of my amps/cabs and reduce the mud (as well as being too caffeinated on a night shift told hold back), how much musical information do you get from a bass guitar fundamental of 30Hz?

At that range, you can feel it, but it doesn't always discern itself as musical information, and is liable to add mud depending on the situation/venue.

I really don't mean to open an unwanted can of worms. Just wondering.

What HPF are you using and how do you like it?

I'm not sure what you mean by musical information. I can give you a specific example. My band does a pretty out there cover of "Lively Up Yourself". There is an extended guitar solo during which we break it down. Guitarist kicks in his Moogfooger and we go into outer space. At this point, I switch from what I've been doing around the C on my E string and go down low to the B string. If it's a gig where I'm using my combo, it's nothing special. If I have one of my 410HLF's, it's compelling.

Some cabs have it, some don't.

I A/B'd my CL with a SS amp and the difference was astonishing. The SS amp produced much more fundamental.

 

[JimmyM]

What SS amp?

 

[Coolhandjjl]

I A/B'd my CL with a SS amp and the difference was astonishing. The SS amp produced much more fundamental.

SS heads have higher damping factors, the ability to keep the cone steady and in control at low frequencies. A conventional tube head has a low damping factor, the cone gets sloppy at low frequencies.

 

[Rip Van Dan]

Got a question for you agedhorse if you don't mind. My understanding of saturating transformers was, especially with tube amps, that once saturated, it generated a distorted signal. Limiting the low frequency response in his transformers was one of the things that Leo Fender specifically did in his earlier guitar amps to saturate the transformer, which resulted in a creamy overdrive sound.

Is saturating the transformer in a bass amp desirable? sometimes? always? Inquiring minds, etc.

Thanks,
Dan

 

[Mr. Foxen]

Saturated transformer distortion sounds like nasty square wave synth. Assume anything Leo Fender did was to make things cheaper to make, and any excuses for doing so are down to the marketing department.

 

[walterw]

Limiting the low frequency response in his transformers was one of the things that Leo Fender specifically did in his earlier guitar amps to saturate the transformer, which resulted in a creamy overdrive sound.

i think it was the opposite, that the earlier tweed stuff wasn't low end limited, and thus broke up earlier, and in a looser, rattier way. IIRC the blackface amps were rolled off, and are thus tighter in the lows even with the built-in EQ scoop, as long as you stay in the amp's clean range.

Saturated transformer distortion sounds like nasty square wave synth. Assume anything Leo Fender did was to make things cheaper to make, and any excuses for doing so are down to the marketing department.

Cheaper sure, but also with the goal of clean, Leo never tried for overdrive on anything.

 

[seamonkey]

As you put more power into a output transformer the more limited the bandwidth is

More power, less bass.

Once you hit saturation, it's clipping. That is regular odd harmonic clipping, with bass compression, straight from the transformer.

All the "Tone" someone claims to hear is heard in the mids and high frequency. Not from sine waves down low. Add a good clean SS powered crossovered sub to reproduce the lows and you'll have more power for the mids and highs from your current amp for all the tone you could want.

 

[Korladis]

Something to keep in mind is that without the super low frequencies somewhat limited, you'll eat up more power producing them.

 

[Jeff Scott]

All of the Fender tube amps I used to own were definitely NOT lacking in the deep bottom end ('66 Bandmaster with a Showman OT, early '70s Princeton Reverb, '62 Concert) when run through various bass cabinets, all ported.

 

[Chris 'Wighat' Jordan]

What SS amp?

QSC RMX 1450

 

[JimmyM]

Got a question for you agedhorse if you don't mind. My understanding of saturating transformers was, especially with tube amps, that once saturated, it generated a distorted signal. Limiting the low frequency response in his transformers was one of the things that Leo Fender specifically did in his earlier guitar amps to saturate the transformer, which resulted in a creamy overdrive sound.

Is saturating the transformer in a bass amp desirable? sometimes? always? Inquiring minds, etc.

Thanks,
Dan

Fender tube amps always sounded to me like they have plenty of low end, even the really old ones from the 50's and early 60's. But you've got it the other way around...Leo built the amps first, and THEN people discovered that cranking them resulted in pleasing distortion. And the reason they saturated early on bass is because Leo used transformers that were big enough for guitar to get clean and loud, but not for bass. And as Seamonkey said, the more they saturate, the low end sounds reduced by comparison. It can be brought up with the tone controls, but that saturates them even more. And that's why Ampeg transformers were always much bigger than Fender, because you could turn them up louder and with more low end response and not saturate them as easily, and Everett Hull absolutely detested distortion and was outraged that it became popular.

Is it desirable for bass? Ronnie Lane thought so:



I always run them clean and use pedals for dirt, though. I need to have clean sounds available, and it's too unwieldy to keep turning amps up and down, plus nobody's letting me dime an SVT on our gigs.

QSC RMX 1450

Well I guess a modern power amp that's designed for PA's probably would have a little bit more low end in it, yeah. But that doesn't mean the SVT lacks. Goes way lower than most cabs can go anyway.

 

[Korladis]

Well I guess a modern power amp that's designed for PA's probably would have a little bit more low end in it, yeah. But that doesn't mean the SVT lacks. Goes way lower than most cabs can go anyway.

I see doom metal bands use SVTs for bass all the time. Definitely no lack of low end.

 

[walterw]

Either way, I definitely have noticed the difference between SS amplification and the CL.

What SS amp?

QSC RMX 1450

wait, we might be missing a detail here; even one side of that amp has more power than a CL head, and if it's bridged then forget it.

all this stuff about transformer low end rolloff could be a total red herring.

 

[EricssonB]

What HPF are you using and how do you like it?

I'm not sure what you mean by musical information. I can give you a specific example. My band does a pretty out there cover of "Lively Up Yourself". There is an extended guitar solo during which we break it down. Guitarist kicks in his Moogfooger and we go into outer space. At this point, I switch from what I've been doing around the C on my E string and go down low to the B string. If it's a gig where I'm using my combo, it's nothing special. If I have one of my 410HLF's, it's compelling.

Some cabs have it, some don't.

I A/B'd my CL with a SS amp and the difference was astonishing. The SS amp produced much more fundamental.

I use this little guy I made a while back; a blending of circuits I copied. Love it. Clears out the lowest parts of the signal, minimizes power-sucking cone excursion, helps the amp to run more efficiently, and prevents 95% of the clipping lights from illuminating no matter how hard I play. Based on this:


By musical information I mean in a conceptual sense of what your ears can discern as music. Quite often, the way-lows can turn into mud and rumble. Like during your ventures to outer space, I'm not saying the low ranges aren't useful, by any means; it's all contextual.

(Edit: Oh boy would I like one of these Mantic Density Hulks:
)

 

[xk49w]

As you put more power into a output transformer the more limited the bandwidth is. More power, less bass.

Works for line output transformers too. The ones that have good low-end and can handle higher power are also higher $$.

All the "Tone" someone claims to hear is heard in the mids and high frequency. Not from sine waves down low.

I used to think that clean reproduction of the low B would be a good thing. But it is costly and involves compromises in size, weight and power. It is also not needed to hear the low B clearly. It is not just the harmonics of the low B that are being heard - rather it is also the intermodulation products of those harmonics. A non-linear mix of the 2nd and 3rd harmonics of the low B produces among other artifacts - a low B. Low B fund ~31 Hz. Low B 2nd ~62 Hz. Low B 3rd ~93 Hz. 93 - 62 = 31 (a low B!).

The non-linear multiplication occurs in the ear, in the speaker, probably not in the amp. Maybe a tube amp at full song I dunno. This technique has been employed for left hand bass in the Hammond organ since Jimmy Smith. Those bass notes that you hear played in the lower octave of the Hammond manual don't exist there, but with the right drawbar setting there they are. And strong. There is no reason an electric bass cannot take advantage of this phenomenon. Just a speculation but rounds may be better than flats - more harmonic content.

 

[CL400Peavey]

The SS amp produced much more fundamental.

I dont think your amp or cab is limiting your fundamental, I think you are running in to the limits of your head room on a 300 watt amp.

 

[teemuk]

Once you hit saturation, it's clipping.

And very NASTY clipping too. Basically equivalent to this:

e.g.
Amp produces full power @100 Hz with very little distortion, (upper waveform=voltage, lower waveform=current)

...But @32 Hz there's just plenty of nasty distortion from OT core saturation:

...And it worsens as frequency decreases. Here's @ 25 Hz:

It is even more evident how during saturation magnetic field just suddenly collapses. So OT saturation is pretty much just very abrupt extremely nasty distortion.

I think it's pretty much just a myth that people would actually like transformer saturation. In guitar amps the bandwidths are fortunately too narrow, in bass and PA amplification people prefer BIG rigs (sans saturation) or overall just using SS amps without transformer coupling. Makes sense to me.

 

[JimmyM]

I think it's pretty much just a myth that people would actually like transformer saturation. In guitar amps the bandwidths are fortunately too narrow, in bass and PA amplification people prefer BIG rigs (sans saturation) or overall just using SS amps without transformer coupling. Makes sense to me.

I would agree with you, except for the butt-ton of bass players out there who like saturation. Some use cranked tube amps, some use SS amps and pedals designed to sound like cranked tube amps, but I hear distortion on bass all over the place. Might not be what you like, but lots of us do like it and don't judge it by what it looks like in a screen grab of a waveform.