[NotoriousBIG_PJ]

I've read that the bass of diy amps is not as good as amps like max and rkv (not suprising giving their prices), but I'm wondering how do those players get such good bass and how could you get better bass out of diy stuff?

Thanks,

Biggie.

 

[jarthel]

I can't speak for other DIY amp designs

but my Kevin Gilmore Pure Class A amp has bass in it. I listened to a Mariah Carey song with lots of bass in it (sort of rap music) and the amp gives out bass even on my AKG K401. This headphones is supposed lean on the bass department. But I have to disagree. With my Philips headphones on the same song, it's like there's a subwoofer inside. It's not like there's a bass boost but bass is there when it's needed.

Jayel

 

[andrzejpw]

the capacitors you use make a big difference.

From what I've read about the meta42, someone compared the bass to the max.

Although I haven't listened to one yet, I'm sort of doubtful.

 

[jarthel]

Good thing Kevin's designed not use caps in the signal path.

 

[puppyslugg]

"...but I'm wondering how do those players get such good bass and how could you get better bass out of diy stuff?"

One of the major difference may be in the power supply. The Max uses a dual psu. I believe erix and aos think the Max uses some sort of Jung/Bobely/Sultzer variation. Not your average, run-of-the-mill psu.

 

[reaction]

The “good” bass depends of the quality/lack of the output capacitors. More money spent in them – much deeper bass you have. Output-capacitor-less designs are even better solutions. My tube DIY amp (based on optimized Morgan Jones design with feedback a.k.a. EarMax clone) has very deep and very articulate bass response with my Grado/Alessandro phones. I have built already the Cmoy, Apheared47 and Szekeres amps and the Morgan Jones design beat them all in terms of sound quality and bass. Just go for it – you can find the schematics at Headwize forum.

 

[jarthel]

Please remember that your source (CD player, LP player and etc.) and other components (preamp and others audio component) also affects overall sound and this includes bass. A good example of this the bass-boost on portable CD players which affects bass alot. Though bass-boost doesn't really give you good bass.

Jayel

 

[kelly]

I feel that I'm probably the person most guilty of promoting the Max and RKV as having the best bass of all the amplifiers I've heard. However, I'd never go as far as to say something like "all DIY amplifiers..." anything. Even within a certain design, part quality and PSU can change dramatically.

What I can say, with authority, is with the META42 in the configuration Tangent built, the bass is very good compared to most amplifiers--but not as good as the Max or RKV.

The RKV is a tube amp so talking about that won't help us much.

Looking inside the Max (there's a pic of the guts on Headroom's site), you can see that most of the power related circuitry is doubled or "split." In other words, the entire power section of the amplifier is dual mono. It's also worth noting that they're using the OPA627, an already somewhat bass-heavy opamp and then running it in AB mode (which I suspect supresses hf details). This combination seems to yield an extremely clean amp with excellent bass response but unfortunately sacrifices a lot in the way of texture and ambient detail to achieve it.

Another commercial amplifier that has relatively good bass response is the Sugden Headmaster. It doesn't quite catch up to the Max, but it's worth talking about. The Headmaster has a completely discrete design but none of if is "split" or doubled. It's also worth noting that in my comparisons, this is the second fastest amp I have heard--second only to the Max.

So... then we have Gilmore's design. Discrete components and able to be run in dual mono. With high grade parts? That could really be something. I wish I could hear one.

I for one am also hopeful about the META42. How much better does the bass get if you stack 3x3 buffers? How much better can it get with the right combination of big and small caps? What about running it dual mono? What about using a Jung super regulated PSU? We don't know these answers yet because the META42 is a new design and hasn't had time to mature with different implementations.

For those of you who expect to be able to best the Max in every way for only $80 in parts, I'm sorry but that's not really grounded in reality. While we could argue about whether the Max at $1800 might be overpriced, if you look inside, you'll know that the parts they chose weren't particularly cheap. This doesn't mean a DIY amp can't catch it in bass response, it just means it may take a little more time, effort and cash.

 

[NotoriousBIG_PJ]

"I for one am also hopeful about the META42. How much better does the bass get if you stack 3x3 buffers? How much better can it get with the right combination of big and small caps? What about running it dual mono? What about using a Jung super regulated PSU? " - kelly

Alright, everyone start testing these mwhahaha... ^^

I always say, go big or go home. Well, thats how I always played Tony Hawk on my playstation...

Biggie.

 

[puppyslugg]

Jarthel wrote:

Quote:

...but my Kevin Gilmore Pure Class A amp has bass in it.

How much of the bass is attributed to the Gilmore's psu? I suspect quite a bit. If you were to substitute a lesser psu, it probably would not have the 'bass slam', and would also affect the overall sound of the amp itself. I doubt Kevin Gilmore would have gone through all the trouble and expense of designing the psu if it he didn't feel it made a difference.

 

[morsel]

Output caps are bass killers. Input caps also damage bass if the cutoff frequency is not low enough, which unfortunately is usually the case. Low output impedance and studly high current power supplies with plenty of capacitance improves bass.

 

[ppl]

All my portable Amps i have Built have a bass Boost switch and i do not consider the Bass Boost topology i use to be less than ideal. In fact IMHO a gental upward increasing closed loop gain at 6 dB per octave provides for the best transient response and this was a complaint i have had of all EQ type of Bass Boost way too sharp of a Boost vs frequency making the bass Boost do more harm that good. so i used the simple R/C network within the feedback loop to do Bass boost and a bypass switch to turn it off. On well recorded Programs i do not use the Bass boost but on those old 60's and 70's rock that lacked good bass from the start. Steppinwolf 16 greatest hits come to mind as being like a transistor radio with-out any bass boost, More output current and Big caps in the Powersupply Greatly help also in addition to numerious other small details.

 

[aos]

Power supply is most likely the reason. That includes power supply capacitors. You just can't compare an amp running on batteries to an amp running on two stage regulated PS (let alone one dual stage per channel). My experiments show jump in quality by two levels if you use good power supply. Most DIY amps you see here are designed to be PORTABLE, and they get reviewed as such. It's a compromise. META42 runs on two small 9V batteries for quite a while. Max doesn't and you wouldn't lug it in a portable CD bag either.

 

[kelly]

aos

I assume when you talk about this that you don't mean just the PSU, but also the differences between components that drain power faster. Ie: Some people use opamp AD823 because it consumes less power, smaller caps presumably use less power, etc. Any time a portable is made, some compromise is made that would typically result in lower quality sound. Thus, even if the amp is designed for both portable and home use (via a Walwart, for example), the compromise has still been made.

The Cosmic doesn't have the dual power circuitry of the Max but still uses power hungry components (like the OPA627) and gets away with this via D cell batteries and a DC->DC converter.

Am I following along so far?

 

[aos]

It's not all black and white I think. If you use big caps but long and narrow traces to chips and headphones, you may get worse results than having smaller caps right at the chips and using wide traces. And so on. The load regulation of the regulator, if used, would also play a factor. Change in output resistance of the amplifier with frequency probably does too. That's why paralleling output buffers (or output transistors like in Gilmore amp) can help. Those are just my guesses though.

Any amp designed for portable use has probably compromised in some feature or other. But that all depends on what designer deemed important. You could have dual regulators and no switching converters on a portable and specify use of lead-acid battery (kind of like Kevin lugs around). Ppl uses 30mF capacitance per channel for a portable amp. I want two independent sets of batteries for my DAC. Everyone has their own opinion of what's worthwile to compromise and what is not.