Just got a Krell 400xi .... now what?

[jai1611]

Amplifer with high damping factor will work well with any kind of speakers because the high damping factor will prevent the back EMF generated by the speaker cone during its motion of the moving coil in its air gap and will not affect the amplifier's output stage. More over in a TL the cone motion is reduced unlike a Vented enclosure due to absence of back-pressure from the enclosure wall. Also the speaker system impedance curve is reasonably flat in a TL and hence will have positive impact on the damping factor.

I dont quite understand the technical reasons behind this but would draw your attention to the following extract from this Nelson Pass paper: http://passdiy.com/pdf/cs-amps-speakers.pdf

Quote:
"The need for electrical damping is different for each type of loudspeaker and acoustic environment. High-efficiency full-range drivers are more easily damped than other types due to their powerful efficient motors and light cones. Looking at their bass response curves, we conclude that they are easily over-damped, resulting in excessive loss of bottom end. This partially explains the preference for tube amps with such loudspeakers. Anyway, this assortment of observations arrived at a confluence when I hooked up a Son of Zen amplifier (Audio Electronics 1997 #2) to a pair of Fostex 208Es in sealed enclosures. The Son of Zen operates without feedback and has an output impedance of about 16 ohms. This nets a damping factor of 0.5, miniscule compared to the 100 to 1000 you can achieve with regular solid-state amplifiers.

With the low damping factor, the Fostex became a totally different speaker. It suddenly had bottom end response and a better top end."


I own a couple of speakers with high efficiency full range drivers. My own experience has been that they dont like highly damped amplifiers.

 

[iaudio]

jai, Sharath of Audire said pretty much the same thing when I asked about pairing tube amps with single driver speakers.

 

[avidyarthy]

I did not understand fully, the below .... maybe, some of you could get things clear from this .....

Fostex Speakers Technical Discussion.

 

[Hari Iyer]

I dont quite understand the technical reasons behind this but would draw your attention to the following extract from this Nelson Pass paper: http://passdiy.com/pdf/cs-amps-speakers.pdf

Quote:
"The need for electrical damping is different for each type of loudspeaker and acoustic environment. High-efficiency full-range drivers are more easily damped than other types due to their powerful efficient motors and light cones. Looking at their bass response curves, we conclude that they are easily over-damped, resulting in excessive loss of bottom end. This partially explains the preference for tube amps with such loudspeakers. Anyway, this assortment of observations arrived at a confluence when I hooked up a Son of Zen amplifier (Audio Electronics 1997 #2) to a pair of Fostex 208Es in sealed enclosures. The Son of Zen operates without feedback and has an output impedance of about 16 ohms. This nets a damping factor of 0.5, miniscule compared to the 100 to 1000 you can achieve with regular solid-state amplifiers.

With the low damping factor, the Fostex became a totally different speaker. It suddenly had bottom end response and a better top end."


I own a couple of speakers with high efficiency full range drivers. My own experience has been that they dont like highly damped amplifiers.

The effect of using a BSC & Parallel notch to dampen the uneven response at the upper mid-range is not extensively covered in the article. Using a full-range drivers without them will be a disastor and due to uncontrolled peaking of the response in the mid & upper mid-range response.

I have to admit that i donot have experience using a valve amplifier to play full rangers and have to go by the experience of the article.

Having a high damping factor in an amplifier is good for them where heavy woofers are connected due to extended excursion at low frequencies to prevent the back EMF from damaging the o/p stage of the amplfier. But when using a Fostex FE206en in a TL alignment the excursion will not be that high. Also the TL enclosure is critical damped in the mid-frequency region and the cone motion is less (also due to a flat impedance curve). The fostex drivers are well suited for a valve amplifier because they behave like a constant current source and are able to pump current to them at low frequencies. A valve amplifier if driven with a huge woofer could damage its o/p stage due to low damping factor and hence a TL does good justice to them. This does not mean than a TL will not due justice to a over damped solid state amplifier.

The fostex FE206en will have to be compensated in the mid-range and upper mid-range for it to be more linear due to its high-low Q points in the FR or else will sound very harsh and fatigue.

 

[denom]

I think the idea is to look for good sound and not 'to fully utilize the power of krell'

That is the 1st object of desire, paramount importance. My POV maybe was 'misunderstood' by you

 

[avidyarthy]

What a tough call ................ !

Had been to Virenji's den today to try out the Krell with, first Amity, then Harmony 1 fullrange speakers. As you all might be aware, Amity is with a 6.5" Fostex and a big Eminence woofer, while the Harmony 1 (TQWT design) is with a single 6.5" Fostex.

With the Krell, running at 1/10th the capable power, it was clear that any further increase on the volume front 'could' damage the fullrange speakers. The output was loud .... very loud, don't think we generally listen at such levels. The Harmony 1 was paaaaaaar excellent ... the speakers vanished on some tracks. Amity was good, but nowhere near the Harmony.

Sets me back thinking ....... things like logistics, price, technical support after setting up, are now coming up. Virenji is just 10 kms from where I put up, while Hari is a cool 1600 kms away!

Anyway, looking at all my impulsive buy history (most have been satisfactory, if not excellent) AND to make use of a major bit of the Krell's strength, something is pushing me to go for the 2 way 'Advanced Transmission Line' from Hari. Specs of the Krypton TL speaker remain the same as suggested earlier .... 5.25" Peerless kevlar woofer and 1" Peerless Aluminium tweeter on a straight TL design.

Have shared everything with Virenji, a thorough gentleman ..... told him of my inclination for the TL even before the audition. He never hard sold any of the USPs of his creations. Even made it a point to connect his tubes and make me hear of the noticeable differences with the Krell, with his speakers. For some tracks the Krell was better to my ears and vice versa. I slightly tend towards the 'bright' signature, maybe thats why.

A 'Thanks' would be too less a gratitude for his gesture ... :clapping:

There goes my coupla nights' sleep, pondering over what to do ... :sad:. DAMN, why did I have to go to Virenji place .... all thanks to GeorgeO!

 

[denom]

Hmmm, a man very disturbed with the 'what should I do now' question mark!

Can you hear me saying (Sell the krell - sell the krell - sell the krell )

:lol:

 

[avidyarthy]

Not at all, Spiro ..... justly 'slightly' warm on the top after long play ....

 

[avidyarthy]

Hmmm, a man very disturbed with the 'what should I do now' question mark!

Can you hear me saying (Sell the krell - sell the krell - sell the krell )

:lol:

Das schweinhund .........

 

[iaudio]

avidyarthy, completely with you on Lyrita Harmony One speakers. Loved it. You should have tried it with the Topping too. As for Viren ji, your experience echoes what many others have said about him, a thorough gentleman and music lover.

 

[square_wave]

Hey Bro,

Krell amps are designed with a certain kind of philosophy in mind. There are many loud speaker designs out there which are designed for powerful amplifiers. The crossover design and drivers used are in agreement with this philosophy. Use the krell if you plan to use them with such loudspeakers.

The loudspeaker designs which you are alluding to require amplifiers created with a completely different philosophy. Such amps are usually low power but with excellent design. They usually sound very good in the first watts they produce. The first watt website is worth a visit to see such solid-state designs. Good tube amps or chip amps are another way to go.

Fostex based speakers, klipsch la scala all will sound okay with the krell. But if you want truly hear their potential; you need to travel a different road

 

[avidyarthy]

@ square wave ......... yes, have become aware of it in quite some 'theoritical' degree now. Maybe, thats why the shift to a 'more' conventional 2 way speaker ... of ATL design.

 

[GeorgeO]

Here I am being blamed! I also agree that using conventional speakers with a high powered amp is probably the best combo.

 

[avidyarthy]

.... hehe ..

 

[denom]

Das schweinhund .........

Garam Kutta ???? With what ref to context??? ???

 

[denom]

@ square wave ......... yes, have become aware of it in quite some 'theoritical' degree now. Maybe, thats why the shift to a 'more' conventional 2 way speaker ... of ATL design.

PMC???

 

[avidyarthy]

Seems like old times ....... why not you do the 'initiation' to the Mumbai PMC distributor ... and I reimburse you in bits and piece aka ... payable when able?

I would love that arrangement for a 'branded' thingy ....... no experimentation too. I would be more than happy with the GB1i model.

 

[srinisundar]

Seems like old times ....... why not you do the 'initiation' to the Mumbai PMC distributor ... and I reimburse you in bits and piece aka ... payable when able?

I would love that arrangement for a 'branded' ....... no experimentation too.

If you find PMC in UK, let me know, i will get you transported in cheaper way.. thatz it i can help you.

 

[denom]

Seems like old times ....... why not you do the 'initiation' to the Mumbai PMC distributor ... and I reimburse you in bits and piece aka ... payable when able?

I would love that arrangement for a 'branded' thingy ....... no experimentation too. I would be more than happy with the GB1i model.

Wheels in motion already

 

[avidyarthy]

SETTLED for the ATL design speakers!
Lets see whats in store .... would come to know in about a month's time .... a blind date, this.