I wonder if anyone can help me? I run a MarkBass Little Mark Tube 500 head. I've been reading a lot about the benefits of a HPF and I would probably get one, except there would not be much point if my head already has one built into its circuitry. I have been trying to find out, but MarkBass don't seem able to answer my question, they just refer me to their service dealers in the US (not helpful when you live in the UK). Do any of you highly knowledgeable electronics gurus happen to know the answer to my question? Thanks guys!
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Markbass - HPF or not? MB don't seem to know!
- Thread starter Robscott
- Start date
I am using pedal HPF with my Little Mark amp. There is a point in using variable HPF with this amp, trust me...
Broughton -- which is well-regarded around here -- offers a couple of different models (plus a combination hi-pass/lo-pass). For 70 bucks I recently bought the "always-on" version, but for $95 you can get a pedal version with a footswitch. I opted for the always-on version because, well, once it's on it stays on. I love it so far: It removes mud that I hadn't even realized was there, and guitarists in both of my bands have commented on how much "punchier" my tone is (which they really like).
The amp most likely has some sort of HPF as it doesn't really make sense to run it all the way down the 0hz. But I don't think that really answers your question. A variable HPF allows you to set the frequency where it is most beneficial, and often the best frequency is higher than the amp's internal fixed HPF.
@Wasnex
Thanks but you can't get Broughton in continental Europe, it seems. Could you perhaps suggest some other brand?
Interesting -- I never thought of it that way. Would you say, then, that most or all amps have (what is effectively) a HPF (as well as a LPF) "built in"?
At any rate, I agree that having a variable HPF would still be useful, as you might well want to set the cutoff higher than whatever is "built into" the amp. The Broughton model I mentioned above starts by default at 20 Hz, and I haven't had to tweak it very far above that -- but this particular model doesn't have the frequencies labeled on the control knob so I can only guess at my cutoff frequency, which I'd guess is around 30-40 Hz. But I can also imagine different cutoffs being optimal for different cabs and different environments, so I'm glad to have the ability to adjust it.
Haven't seen an amp yet that is flat from DC to Gamma. So IMHO, yes every amp has some sort of filtering going on, whether it's intentional or not.
Passinwind
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- Dec 3, 2003
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You can test the frequency response correlation to control position yourself with freeware such as Room EQ Wizard, or even some VSTs IIRC, and a basic audio interface.
That's weird the FAQ seems to infer they ship internationally.
FAQs | Broughton Audio
The only dedicated HPF I can find that is made in EU (UK) is the SFX Micro Thumpinator, but unfortunately it is not variable.
Schalltechnik (Germany) offers a very nice HP-LP pedal (named "Vong") in kit form if you're handy that way.
You're right, they do ship internationally but in this case (namely, not purchased from an EU distributor) shipping plus import taxes means more than double the retail price, so about US$250 for the HPF pedal...
The Vong looks cool! I wish they'd sell it assembled and ready to go. I've done some basic soldering alright but...
Any rationally designed bass guitar amplifier has a high pass filter somewhere in its circuitry. If it didn't, the attack of every note (when you pull on the string, before you release it and it vibrates) generates sub sonic information - without a high pass, that information/signal will move your woofers a LOT (without creating usable sound). The odd thing is that this is something nobody ever talks about in their amplifier literature - the only amplifier I ever saw talk about it was a line of Acoustic amp heads that touted they DIDN'T have a high pass filter - they were DC coupled. It was a STUPID idea - a 100 watt amp that couldn't get very loud at all, as it wasted all it's headroom on those transients. That line and the marketing campaign quickly and quietly disappeared - once the amps were out in the real world, they realized their mistake, stopped making those models, and never spoke of DC coupling again.
That said, a lot of folks on here like their high pass frequency to be set higher than what's in the amp (whatever it is, which they for some reason don't tell you) - to reduce the amount of strain put on the speakers on the lowest notes. In that case, you need an external high pass filter.
The micro thumpinator is a good product for reducing subsonic stuff. It's not what you want if you're trying to lop off some of your fundamentals - it's designed to not do that.
That said, a lot of folks on here like their high pass frequency to be set higher than what's in the amp (whatever it is, which they for some reason don't tell you) - to reduce the amount of strain put on the speakers on the lowest notes. In that case, you need an external high pass filter.
The micro thumpinator is a good product for reducing subsonic stuff. It's not what you want if you're trying to lop off some of your fundamentals - it's designed to not do that.
Can a compressor or a booster also have - even if only approximately - the effect of a HPF?
By the way, I asked for information on the EQ center frequencies of the AMT A-Bass and O-Bass preamp pedals and the company tech support Alexander Korotaev kindly send me the following files. Can't really figure out what they mean, perhaps they do function as HPF or LPF filters to an extent.
In my case I'm not hearing any unwanted low end noise, it's just that I want my stage rig and pa to be working as efficiently as possible, not amplifying stuff that no-one can hear. That sounds like a good reason to have a HPF if the amp circuitry doesn't do that job well enough. Reading between the lines it seems like there's a good case for a variable HPF regardless the amp. BTW your other posts on this subject have been highly informative, thanks a lot! I will probably snag a variable Broughton from the US, or there's one made by Rafferty in the UK which I might look into......
There is a guy in Poland that makes variable HPFs for around 40€. Here's a contact [Invalid or Expired Link Removed]
I don't know why he doesn't have the HPF on his site, but it is available on the local substitute for Amazon
Invalid Link Removed
He also sells them as DYI kits and for them he has an english site and international shipping options High Pass Filter / HPF kit ULTRA
I have a HPF and a LPF from him, as well as a compressor built on his design and I love them all.
A HPF looks like this
So they don't really function as a HPF. Just as a tone control.
