Quiet amplifier

[kctess5]

One of my absolute hugest pet peeves is hearing buzz coming from my speakers. When there is a definite frequency audible that is the worst, but wide range white noise is also pretty bad. I have heard some VERY high quality gear and I've never understood how audible noise is acceptable from amps/dacs that cost ~$4000+, why would anyone spend that much on a noisy component?!

I'm looking for a lower power amp that is particularly quiet. It will be used with speakers that are 95dB efficient so 10 to 15 watts is enough for me. The noise should be inaudible from no more than about a foot away from the speakers, though less than that is welcome. I have googled this a fair amount and all I can find is people talking about specific op amps and components.

Class A is preferable, though AB is ok, and I *might* consider class D. Tube amp suggestions are also welcome, as long as they are well reputed. I would like to stay under $250 though will take suggestions that are a little higher, I am on a pretty low budget (almost a college student). I don't want to do a kit because all the kits I have made have been very noisy, presumably because of my mediocre wire routing.

Thanks!

 

[chris661]

If college may happen shortly, I'd avoid valves (AKA tubes at your side of the pond ). You don't want to have to worry about damaging/replacing them, as there are other things you should be spending money on.

I've got an amp6-basic from 41Hz, powered by a 12v 5A laptop PSU. Had it for years, and it just keeps working.
IMHO, it'd fit the bill nicely: it'll provide enough power in a compact form-factor, and sound decent doing so.

I'm using it to drive >500Hz into a pair of Fostex FE126s. Noise is just about audible with my ear next to the cone, but given the stupidly messy wiring of my current stereo, its hardly surprising there's noise.

I know you said you don't want a kit, but this'd probably be <$100 all done.

Chris

 

[xrk971]

I second that class D amps are the way to go if you want low noise, which is counter-intuitive because traditionally you want to keep digital switching away from analog components to reduce noise. Note that tubes are inherently higher temperature devices and will intrinsically have more noise (thermal), all else equal. The bigger problem is 60 Hz line freq hum leaking in due to ground loops from bad design or bad construction techniques.

 

[vacuphile]

I second what Chris and xrk971 said about classD. Certainly with a budget of 250 USD, that's the way to go. 41Hz has some very affordable kits.

 

[IG81]

If a used amplifier is acceptable, you can get a Yamaha M-45 for your budget. It's way more powerful than what you say you need at ~120W, but that's not a bad thing in my book. You can run it in class A up to ~10W IIRC and its self-noise is extremely low. I use mine to drive 113dB/W/m compression drivers on a bi-amped two-way and have no problem. If components upstream have noise of their own, you can turn down the input level on the Yamaha and keep SNR higher upstream.

IG

 

[cyclecamper]

A lot of push-pull tube stuff was designed thinking they can get away with terrible power filtering for the power output stage because in theory the push/pull cancels hum from the power supply. In reality, the splitter is never perfect, the push and pull sides are never perfectgly balanced, the bias supply gets polluted, etc. etc.

 

[ssportclay]

Since your speakers are so efficient, all you need is a little class D amplifier. One of the little Topping Tripath chip units would be the obvious choice. The newer Texas Instruments digital amplifier chips seem to be getting a lot of attention lately. Look at the Muse Audio M50, Guanzo DP-101, or FEI XIANG FX502A. These all use the TI TPA3123 chip if you want to try something different than a Tripath. You could also try a TPA3116D2 or TPA3118D2 evaluation module but you will need a 24 volt/4 amp power supply and you will not have a case if you care. Texas Instruments released those last 2 chips last summer so they are very new designs.

 

[Bob Brines]

I have the big Topping which is based on the TA2020. I love it, but all of the Tripath chips are getting long in the tooth. I need to get one of the new TI amps. I'll look at the suggestions above. Needs to be 20w/ch or greater.

Bob

 

[kctess5]

I've had mostly class D amps. They just seem a little lifeless and I was hoping to get something class A. I'll have to check out that Yamaha M45.

I am currently using a bit of a hotrod 41hz amp-6 basic. A friend of mine made it, it's got some high quality caps installed and stuff. It's pretty good but I can still hear a bit of a buzz, and the wiring looks like it should be lower noise.

 

[xrk971]

I just got my TPA3116D2 chip and all the caps and resistors to go with them, should be starting the build soon. It's a little hairy because the amp is a 0.6 mm pitch SMD and parts are like dust bits. iIRC 50 watts/channel and 0.1 %THD at 30 watts w 24v supply.

 

[ssportclay]

I have the big Topping which is based on the TA2020. I love it, but all of the Tripath chips are getting long in the tooth. I need to get one of the new TI amps. I'll look at the suggestions above. Needs to be 20w/ch or greater.

Bob

I also have a Topping TP-60. Its most definitely a good and well made amplifier but my belief is that the Tripath chip technology is getting outdated. One comment on the TPA3116D2 evaluation module with no modifications is that it still sounds very good at very low volumes.This is usually a sign of a very good amplifier regardless of power.

 

[lanchile]

M400!

I have had some good amps like Bryston But I always heard back noise when I put my ears next to the tweeters...I never liked it , I spent around $3K in amps and "all" had back noise, do not get me wrong here, they sounded fantastic but that was one of my reason to sell them and build my own diy amp. I build many diy amps but there was something about sound quality. all this stopped when by mistake I was looking for amps using 2SK1058 outputs, since these transistors are very well known for their sonic quality. Well I found these:2sk1058 2sk2221 irfp9240 mosfet amplifier schematic I gave a shot and I build the M400 and I was shocked how good it sounded and all what they said about these amps are TRUE!.I have build so far four of M400 amps and one T300 from them too, but I like the M400 better and I always get the same fantastic sound, I put the tweeters "touching" my ears and I do not hear a fart as a back noise. I can put these M400 next to "any" Bryston amps and the M400 will give a fight with one hand down . so far it is the "only" diy amp that I am sure it will give me what I look for.

 

[Bob Brines]

I am currently using a bit of a hotrod 41hz amp-6 basic. A friend of mine made it, it's got some high quality caps installed and stuff. It's pretty good but I can still hear a bit of a buzz, and the wiring looks like it should be lower noise.

Could be power supply artifacts. The neat thing about the Topping TP-60 is that it does not use a SMPS. Instead it has two large toroidal transformers. It has just the slightest hint of 60Hz hum. Gives it a bit of a tubey sound.

Bob

 

[ssportclay]

Could be power supply artifacts. The neat thing about the Topping TP-60 is that it does not use a SMPS. Instead it has two large toroidal transformers. It has just the slightest hint of 60Hz hum. Gives it a bit of a tubey sound.

Bob

Power supplies are hotly debated when used with digital amplifiers or any others for that matter. Some say that SMPS are fine. Some like linear regulated power suppliers. Others say to use only linear regulated power supplies in a different container attached with an umbilical cord. Even others say that converting AC to DC is evil and use nothing but batteries. Its very easy to just buy a SMPS because they are readily available but sound quality could be greatly compromised.

 

[studio]

'what they said about these amps are TRUE!.I have build so far four of M400 amps and one T300 from them too, but I like the M400 better and I always get the same fantastic sound, I put the tweeters "touching" my ears and I do not hear a fart as a back noise. I can put these M400 next to "any" Bryston amps and the M400 will give a fight with one hand down . so far it is the "only" diy amp that I am sure it will give me what I look for.[/QUOTE]


Hey Lanchile, i just got back to "Diy" after a long break..I had spent more time in the past building almost every schematic amplifiers i could find in the web than listening to music! I finally settled with a musical fidelity amplifier and shelved my soldering iron. The sad thing is, i have not powered up this amplifier for the last 6mths,..i never knew the reasons why.

Out of boredom and many good things i 'd heard and read about T300,
I finally got a pair in my mail box. The moment i fired it up, I am hooked to music again! The first thing i noticed was the realism of brass instruments and lower frequency response. I could tell the difference because I played the clarinet when i was in high school and now i have an acoustic piano and taylor guitars sitting in my home. I used to think that recording put emphasis on vocals and the backing instruments behind.
T300 changes that! With it i could hear every single nuance, expression, variation in color and tone,. Very precise reverb that gives an accurate staging,. i could now tell the positions of the vocals, drummer, keyboardist and bassist in a recording!

Which input cap are you using? The input cap that came with the kit seems
like a power supply capacitor.

 

[kctess5]

I might have to try out one of those H/D amps. They look pretty nice. Higher power than I needed but that's ok. They are a bit outside my price range for now, but maybe I will be able to swing it at some point.

 

[zman01]

A compact option for tubes/valves:

Appj PA0901A EL84 12AX7 Mini Tube Amp Original Miniwatt N3 2012 New Version | eBay

I have heard the Mini-Watt N3 and it was very sweet sounding. Played well (and pretty loud) with plenty of detail with the Fostex FE166EN which is around 94dB efficient IIRC. The Mini-Watt N3 came with a Tungsol 12AX7 and a pair of Sovtek EL84.

Have no experience with the APPJ amp above but ordered one and expecting to receive in April.

 

[kctess5]

A compact option for tubes/valves:

Appj PA0901A EL84 12AX7 Mini Tube Amp Original Miniwatt N3 2012 New Version | eBay

I have heard the Mini-Watt N3 and it was very sweet sounding. Played well (and pretty loud) with plenty of detail with the Fostex FE166EN which is around 94dB efficient IIRC. The Mini-Watt N3 came with a Tungsol 12AX7 and a pair of Sovtek EL84.

Have no experience with the APPJ amp above but ordered one and expecting to receive in April.

Can you let me know how it sounds and what the noise floor is like?

 

[Mooly]

I've moved this over to the Solid State forum... seein' as its all about amps.