[Steve Eddy]

Steve Eddy, you are hilarious! I almost fell off my chair laughing about your comment and picture. 

Almost? Well, my insurance is paid up so I'll try a bit harder next time. 

I've never seen donkey dicks, and now you are making me even more glad about that!

Yeah. The experience can be quite a blow to the ol' male ego. 

se

[Steve Eddy]

George is a really cool guy. He let me bring my speakers and amp to audition the pre amps. How many guys will let you do that?

Sadly not many these days.

Sorry, I missed your suggestion about the Burson. I've heard about it before. I was just reading about it. Sounds interesting. This stuff is way over my head though. It talks about maintaining the same voltage, but lowering the impedance.

Yes, which is what a "buffer" does. It presents the source with a high input impedance while providing a low output impedance and usually keeping the signal level the same, though the Burson does seem to provide 6dB of voltage gain.

See, I just learned something new. Ok, now I'm curious as well. Steve Eddy. what are your thoughts on applying this Burson thing to better drive an amps input? ( considering the modded SB's output of 1.1 volts, not sure of the impedance though)

Well, the amp's input shouldn't be a problem. What typically becomes problematic are the cables. If they're unusually capacitive or unusually long, when you combine that with a high output impedance, you can not only end up with high frequency rolloff (the output impedance and cable capacitance form a low-pass filter), but the output driving the cable can just run out of steam and not have the current capability to drive the cable's capacitance, which presents a lower and lower impedance as frequency increases.

Anyway, back to the Burson, unless the SB has problems driving the cables, the Burson is pretty much just functioning as a means to provide a bit of voltage gain, which could be done passively with a transformer if the situation's right.

Or what about that TVC thing I keep seeing posts about on AC? Man, there's like 64 pages on that thread!

A TVC could work too. Though as much as I like transformers, I still can't quite bring myself to get on the TVC bandwagon. But that's just me. Many people love them and you may too so don't dismiss them.

And yes, I'm starting to feel neurotic about all of this, I've reached that slippery slope thing, and I guess I've fallen off. 

In the words of Luke Skywalker...

NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!

[Steve Eddy]

What exactly would the net effect of the Burson be? Would it up the voltage to the amp input?

Yes. It has 6dB of gain, so it would double the voltage from the SB3.

se

[NewBuyer]

Daygloworange, and especially Steve Eddy,
What do you think of the idea, of using the chain SB3 -> Burson Buffer -> Endler Attenuators -> Amp.
It seems this would give the desired voltage/current/gain boost from the SB3, and easily drive the signal through the amp - in fact you could use several Y-adapters with the Burson unit with no performance drop.
Your thoughts please?

That'd be fine, though unless you're intending to put Burson Buffer right at the output of the SB3 and the Endler Attenuators right at the input of the amp, I'd recommend putting the Endler Attenuators right at the input of the Burson Buffer.

se

Very interesting suggestions Steve - thanks! I hadn't considered attaching the Endler Attenuators on the Burson Buffer, instead of the amp.

Could you please speculate: Which location for the Endler Attenuators (amp inputs, or Burson Buffer inputs) do you think is preferable, and why? The Endler Attenuators are 4k shunt-type, so something like the Burson Buffer can drive a signal through these Endlers effortlessly, and the system noise floor is greatly improved too when using the Endlers directly on the amp inputs (no cable capacitance issues to worry about either). However, the config you suggest would allow attenuation of all (possibly y-adapted) output signals from the Buffer equally, thus eliminating any need to dial-down the subwoofer for level matching - but the source would also then be trying to drive the signal through the 4k attenuators, instead of the much higher amp/preamp input impedance.

What do you think please?

[Daygloworange]

Ok, here I was thinking that after one or two posts I'd be off on my way.......As someone who doesn't have strong fundamental knowledge of EE, I find this stuff makes my head spin, and gets me frustrated. The deeper I delve into it, the more I realize my limited understanding of it.

As it stands now. I'm not sure which is the way I'd like to go, There seems to be a number of alternatives to overcome the modded SB 3's low output voltage. I'm not sure I'm understanding all the passive pre-amp stuff very well though.  And all the impedance and capacitance stuff too. An increase of 6 db's of voltage? I didn't know you could increase voltage by db's. Or is it increasing the voltage (in volts) with the net effect being a 6db increase in output of a device? Isn't 6db what our hearing perceives as twice as loud?

I think I understand it one minute, then I read something else, learn something else, and end up scratching my head a little more.

The Burson thing appears to be a DIY module, correct? And it's not passive, right?

I'm a little lost now. Which one was transformer based? Which ones are passive? Which ones are buffered?

Which one would be the most sonically transparent?

Holy cow! No wonder people just go out and buy a Bose radio! (just kidding, no hate mail please.)

Cheers

[NewBuyer]

...The Burson thing appears to be a DIY module, correct? And it's not passive, right?...

The Burson Buffer I refer to is a plug-and-play component. Here's a link...

[WEEZ]

NewBuyer,

The 'passive' box I tried was a friend's. It's nothing more than a Goldpoint series stepped attenuator in a box. 25k value, I believe.

WEEZ

[Steve Eddy]

Could you please speculate: Which location for the Endler Attenuators (amp inputs, or Burson Buffer inputs) do you think is preferable, and why? The Endler Attenuators are 4k shunt-type, so something like the Burson Buffer can drive a signal through these Endlers effortlessly, and the system noise floor is greatly improved too when using the Endlers directly on the amp inputs (no cable capacitance issues to worry about either). However, the config you suggest would allow attenuation of all (possibly y-adapted) output signals from the Buffer equally, thus eliminating any need to dial-down the subwoofer for level matching - but the source would also then be trying to drive the signal through the 4k attenuators, instead of the much higher amp/preamp input impedance.

The rationale for where to place the Endler Attenuators essentially boils down to cable capacitance.

The cable's capacitance, combined with the output impedance of whatever is driving the cable, forms a low pass filter. The greater the cable capacitance and/or the higher the output impedance, the lower the cutoff frequency will be, and vice versa.

One of the primary purposes of a buffer such as the Burson is to provide a low output impedance, which for a given amount of cable capacitance, will keep the high frequency rolloff higher than something with a higher output impedance.

It therefore doesn't make any sense to have somehting like the Burson Buffer and its low output impedance only to stick an attenuator right on its output which will only increase the output impedance and subsequently lower the high frequency rolloff due to cable capacitance.

So...

That leaves you with two other possibilities. Putting the attenuator right at the amplifier input or at the input of the buffer. This way, in both instances, the cable capacitance is being driven by the low output impedance of the buffer.

This help?

se

[Steve Eddy]

Ok, here I was thinking that after one or two posts I'd be off on my way.......As someone who doesn't have strong fundamental knowledge of EE, I find this stuff makes my head spin, and gets me frustrated. The deeper I delve into it, the more I realize my limited understanding of it.

Awwww quit yer whinin'! 

As it stands now. I'm not sure which is the way I'd like to go, There seems to be a number of alternatives to overcome the modded SB 3's low output voltage. I'm not sure I'm understanding all the passive pre-amp stuff very well though.  And all the impedance and capacitance stuff too. An increase of 6 db's of voltage? I didn't know you could increase voltage by db's. Or is it increasing the voltage (in volts) with the net effect being a 6db increase in output of a device? Isn't 6db what our hearing perceives as twice as loud?

dBs, or Decibels is just a logarithmic expression of the ratio between two quantities, and is routinely used to express voltage, current and power ratios.

For voltage and curent ratios, it's dB = 20 x log(V2/V1) or 20 x log(I2/I1). For power ratios, it's dB = 10 x log(P2/P1).

So, if you double the voltage, say from 1 volt to 2 volts, 2/1 = 2, and the log of 2 is 0.3. 20 x 0.3 = 6, or 6dB. Similarly, if you double power, say from 1 watt to 2 watts, then 10 x 0.3 = 3, or 3dB.

As for our perception of loudness, which has a large subejctive component to it (i.e. one person's notion of what sounds twice as loud isn't going to necessarily going to be the same as some other person's notion), it's been shown that on average, it takes a power increase of about 9 or 10 dB.

10dB corresponds to a ten fold increase in power. So all else being equal, 10 watts of power sounds about twice as loud as 1 watt of power. 100 watts of power sounds about twice as loud as 10 watts of power. 1,000 watts of power sounds about twice as loud as 100 watts of power, and so on.

So, if you double the voltage coming out of the SB3, you increase its output by 6dB. Doubling the voltage coming out of the SB3 will also double the voltage your amplifiers puts across the speaker terminals (provided the amp's not clipping of course). Doubling the voltage across the speaker terminals will quadruple the power delivered to the speakers. But since we're multiplying the log of power ratios by 10 instead of 20, you get a 6dB increase in power.

Simple, isn't it? 

se

[Steve Eddy]

The Burson Buffer I refer to is a plug-and-play component. Here's a link...

Hehehe. I like this one:

We have putted our Audio Buffer kit into an absolutely beautiful case.

Er, "putted"? I sure hope their engineering skills are better than their English skills. 

se

[Daygloworange]

10dB corresponds to a ten fold increase in power. So all else being equal, 10 watts of power sounds about twice as loud as 1 watt of power. 100 watts of power sounds about twice as loud as 10 watts of power. 1,000 watts of power sounds about twice as loud as 100 watts of power, and so on.

Yeah, ok, now I remember being taught that. It's a square thing. Cool.

Thanks for the other definitions as well. It's helpful. Even though I won't retain it all at this moment, it definitely helps understanding things.

Cheers

[NewBuyer]

...That leaves you with two other possibilities. Putting the attenuator right at the amplifier input or at the input of the buffer. This way, in both instances, the cable capacitance is being driven by the low output impedance of the buffer...

Hi Steve, thanks but what you've just said is already contemplated in my last post. I was wondering which of these specific two location options for the Endlers (mounted on amp inputs, or mounted on Buffer inputs), you would speculate to be preferable? (I listed some pros/cons of each in my last post too)

What do you think?

[Steve Eddy]

Hi Steve, thanks but what you've just said is already contemplated in my last post. I was wondering which of these specific two location options for the Endlers (mounted on amp inputs, or mounted on Buffer inputs), you would speculate to be preferable? (I listed some pros/cons of each in my last post too)

Oh, ok. Sorry 'bout that.

Which would be preferable would depend on your situation.

For example, if you're wanting to laterally bi-amp, or are feeding an active subwoofer and you want to control volume for all of the other inputs, then putting the attenuator at the front of the Burson would be preferable. If you're just going to be driving a single input, then I would put them at the amplifier inputs as this would give the best signal-to-noise performance.

se

[Occam]

I've not heard the Burson, nor have I heard the SKpre from a poster on these boards, AmplifierGuru (Gregg Ball). But I believe you could configure this low cost, high value module for a fixed gain, like the Burson, and apply magnetic attenuation as you've been discussing.
http://www.audiocircle.com/index.php?topic=33556.msg311045#msg311045

[NewBuyer]

...you want to control volume for all of the other inputs, then putting the attenuator at the front of the Burson would be preferable. If you're just going to be driving a single input, then I would put them at the amplifier inputs as this would give the best signal-to-noise performance...

Thanks Steve Eddy, but note I already said all this in my same previous post too. I was asking you if you had anything else to add to these considerations.

Steve I thought you said you were giving up crack for the New Year? (Just teasin ya) 

Hope you and everyone else has a Happy New Year!

[Steve Eddy]

Thanks Steve Eddy, but note I already said all this in my same previous post too. I was asking you if you had anything else to add to these considerations.

That may have been what you intended to ask, but what you actually did ask was simply for me to speculate on which of the two location options for the Endler Attenuators would be preferable:

I was wondering which of these specific two location options for the Endlers (mounted on amp inputs, or mounted on Buffer inputs), you would speculate to be preferable? (I listed some pros/cons of each in my last post too)

I don't see anything in that asking me to add to the considerations. So I replied saying that which would be preferable would depend on the situation. Nothing I can add to that I'm afraid so it'll just have to do young man.  

Steve I thought you said you were giving up crack for the New Year? (Just teasin ya) 

Well, t'ain't the new year yet.

Hope you and everyone else has a Happy New Year!

Thanks! And the same to you and yours!

se

[NewBuyer]

Ok thanks Steve!

And please, if you do think of any additional considerations about these alternative location ideas (i.e. besides those already mentioned ), I would still appreciate you sharing them. I can always learn something new from your posts! (Well almost always hehe)