[AKSAphile]

I would like to replace my great AKSA 100N amplifier with LF. My partnering speakers are 2way 8 ohm 86-87dB, relatively easy to drive. After reading some reviews here on the forum, I am little bit confused which LF amplifier to choose. If I understood correctly, LF 55 has better bass definition and dynamic headroom as AKSA100 N. But watts are still watts and I would like to know in what situation is better to use LF 100 instead of LF55? Maybe in a case of inefficient loudspeakers, or higher than normal listening session..?

Now I am use combination of AKSA 100N and OPA 134 input buffer and sometimes I listen on higher listening level, but till today I never clip the amplifier.

My budget is limited to LF55, but since this should be the amplifier for years to come, I rather ask twice than purchase once

[DSK]

If the question is LF55 or LF 100, there is no question... LF100!! They sound virtually identical but the LF100 is even more dynamic and unrestrained, with an even greater sense of effortlessness.

If the question is 100N+ or LF55, there still is no question .... LF55!!  The LF's are a major step up from the earlier series with improvements in almost every area. The bass and dynamics of the LF55 were at least equal to the 100N+ and it sounds like a much more powerful amp than the 55N+.

[Tliner]

I have heard the LF55 and the LF100 MK 11 and the Soraya amp one day when fine tuning the VSonic speakers. Each amp is better than its predecessor. It all depends how long one is prepared will wait to save up the vital amount of $$$. I would like to own a Soraya!

Cheers,

Laurie

[AKSAphile]

Thanks both for comments...

The bass and dynamics of the LF55 were at least equal to the 100N+...

Well, that explain a lot to me...

[AKSA]

Andrej,

The LF55 is suitable for all but the very largest applications, where maybe sound levels are very high, and/or speakers are inefficient, and/or the room is very large.  It's very powerful sounding, largely because of the output impedance, which is very slightly negative.

The principal improvement over the AKSA 100N+ is resolution and imaging, with quite a bit more bass, and a clearer, more accurate top end.  It is not as warm as the AKSA, but it has a sense of 'intimacy', because you feel, with the high resolution, that you are 'in' the recording.

Hope this helps, it's a difficult decision,

Cheers,

Hugh

[AKSAphile]

The LF55 is suitable for all but the very largest applications, where maybe sound levels are very high, and/or speakers are inefficient, and/or the room is very large.  It's very powerful sounding, largely because of the output impedance, which is very slightly negative.

The principal improvement over the AKSA 100N+ is resolution and imaging, with quite a bit more bass, and a clearer, more accurate top end.  It is not as warm as the AKSA, but it has a sense of 'intimacy', because you feel, with the high resolution, that you are 'in' the recording.

Thank you Hugh for explanation. I am still very happy with AKSA 100N and I cannot imagine how good amp could be much better with LF55 ...

There is only one small ? here...the amplifier environment. In few years I tested various preamps with AKSA and I learned that with my speakers, room and musical taste, my AKSA amp benefit with clean sounding preamp. Any preamp with the warm (H2) character was simply to grainy and too warm with the AKSA .I achieve good results with passive preamp. The sound was simply more fresh and natural, but the bass was not so well defined and top end of spectrum was somewhere less transparent. Simple op amp buffer with unity gain was the best choice with AKSA...

...but now with my LF55 I will probably need to re-arrange my system a little bit. How LF55 respond being driven with passive volume pot  compared to AKSA? Due lower levels of H2, it probably need some tube help here, or not?

[AKSA]

Andrej,

I agree with your observations, though I do feel the AKSA benefits from the GK1.

The LF will be very happy with a good passive;  the 'intimacy' I referred to, the 'thereness' of the sound, likes a super clean source, no question.

I am presently thinking about preamps for the LF/Soraya.  The teflon in front of the preamp makes a difference, there is no question that the higher resolution afforded a very good input cap is important and much noticed on the Swift/GK1, particularly when used with the LF/Soraya.

Cheers,

Hugh

[AKSAphile]

The LF will be very happy with a good passive;  the 'intimacy' I referred to, the 'thereness' of the sound, likes a super clean source, no question.

OK.


Anyway why I experience a little bit less defined bass and some masked sparkle and detail driven AKSA 100N with passive pot? My CD player has analog stage made of opa 2134 with 2,2 uF blocking cap and it is connected to amp via 10k log pot. DACT attenuator calculator say that everything should be OK, but in practice I got the feeling that there is some hidden impedance mismatch...this is probably the reason why there are more details and transparent sound when some  unity gain buffer is connected in chain.

[VYnuhl.Addict]

Hi Aksaphile,

 
   Just noticing your details on output, with the opa2134 dc offset is so low you should be able to remove those output caps, they are a detriment when you can get away with it, assuming that you have retained the input caps on your amplifier. At this stage I swear by a good passive when you can get away with it, though I have also very selectively chsoen the op amp in the 4th order lpf network in my cd player and added a output buffer based loosely off of walt jungs ideas, which drives a passive with ease and with an Aspen amp its sonic Nirvana. Still if those OP coupling caps are electrolytics you will notice a big difference removing them, also there will be much less interation and rolloff with the Passive, just make sure you use short cables, lowest capacitance realistically possible to avoid premature HF rolloff.


Colin

[AKSAphile]

   Just noticing your details on output, with the opa2134 dc offset is so low you should be able to remove those output caps, they are a detriment when you can get away with it, assuming that you have retained the input caps on your amplifier. At this stage I swear by a good passive when you can get away with it, though I have also very selectively chsoen the op amp in the 4th order lpf network in my cd player and added a output buffer based loosely off of walt jungs ideas, which drives a passive with ease and with an Aspen amp its sonic Nirvana. Still if those OP coupling caps are electrolytics you will notice a big difference removing them, also there will be much less interation and rolloff with the Passive, just make sure you use short cables, lowest capacitance realistically possible to avoid premature HF rolloff.

Hello Colin.

I will go a little bit into details...My current CD player is NAD 541i. This CD player has very good power supply regulation - shunt with LM 317 /337 regulators with Nichicon muse capacitors. Original this CDP has 2604 opamp at the output per channel (filter + output buffer) followed by 100uF Nichicon Muse as DC blocking cap. 100uF was originaly bypassed with some unknown MKT caps.

However, I did some modifications...at first I replaced mute tranzistors at the output with wire link, then I replaced 100uF caps with Mundorf 2.2 uF MKP caps. Next I replaced opa 2604 with 2134. The last modification was replacing 4007 diodes in analog supply with schottky type. The result was outstanding...greater transparency, headroom. In all areas I feel there was a major upgrade...


I will try to replace MKP caps with wire link soon and then try passive variant again...

[Occam]

AKSAphile,

I'm not a particular fan of the OPAx134 opamp. Typical BurrBrown sound, and if that particular warmth is what you like (I do), IMO, the OPA2107 is preferable and is simply mo betta. Alternatively, the National LM4562/LME497x0 is about as clean and extended as I've heard in an opamp. A chip that sort of splits the difference is the AD8599, which unlike the former, is only available in SMD.

Inevitably, I find myself using both the 2107 and National chips in combination where possible.

FWIW,
Paul

[AKSAphile]

I'm not a particular fan of the OPAx134 opamp. Typical BurrBrown sound, and if that particular warmth is what you like (I do), IMO, the OPA2107 is preferable and is simply mo betta. Alternatively, the National LM4562/LME497x0 is about as clean and extended as I've heard in an opamp. A chip that sort of splits the difference is the AD8599, which unlike the former, is only available in SMD.

The LM4562 opamp is long on my wish list, problem is that it is not so easy to get them here in EU for good price and I am a little bit curious  if it can simple replace 2604 or 2134...

[VYnuhl.Addict]

Hi Aksaphile,


    I must apologize to Hugh, this thread has become quite off topic but here goes. Replacing the 2.2uf with a wire link will be very beneficial in transparency as no cap is always better than any cap circuit permitted, even a teflon . I had a glance at the c541i schematics and notice the OP Amp,LPF filter network is very similar to my Rotel, first half of opa2604=dac buffer, passive lpf and then a unity gain output buffer on the same dual chip as the PCM1732 is a Voltage out single ended DAC with onboard I/V conversion the outputs are configured as followers to take the load off of the dac op before the lpf. I found my magic mix came with an OPA627 for the dac buffer and a modified ad744/ad811 composite for the unity gain output, very heavenly sounding as the 627 has a transparent relaxed sound which compliments redbook cd playback. But this took much reworking of the pcb and well lucky for me I dont intend to resell the player, .  But I can guarantee you will notice a difference passive or no passive by removing the output coupling caps as with the opa2134 dc offset is typically well under 1mv being a FET input op, just keep the amplifier input coupling cap in...

Hope this helps a wee bit
Colin

[AKSA]

Colin, Andrej,

Great advice - though always a bit suspicious about unprotected sex between source and amp - but really sound nonetheless.....  many thanks Colin!

Cheers,

Hugh

[kyrill]

what gives the best experience Hugh?
With or without?

[Oz_Audio]

Unprotected Sex is always better

Don't you just love the internet, 95% or something is Sex related and we have just added to that statistic.

Now my favorite sites are www.................................... ......

[AKSA]

Ahem, Kyrill,

This is difficult.  Let's see.  More pleasure, unprotected.     Safer, protected.    

Age and inclination definitely enter into these weighty considerations.     Perhaps Mr Mugabe is thinking on these matters as we speak.    Maybe I should stop now? 

Cheers,

Hugh

[kyrill]

ah hem
i was of course referring to a better musical experience with or without output caps, no?