[AB]

I've been holding off more comments on the KWA until I put some more hours on it and had a 36.5 in place to feed it - the amp has about 500 hours on it and a 36.5 is now in place.

So how many hours do you have on your 36.5?

It's been my experience the 36.5 takes about 400 hours to get where it's going.

[Philistine]

I've been holding off more comments on the KWA until I put some more hours on it and had a 36.5 in place to feed it - the amp has about 500 hours on it and a 36.5 is now in place.

So how many hours do you have on your 36.5?

It's been my experience the 36.5 takes about 400 hours to get where it's going.

At least 15 hours - so it looks like it will get even better.
I'm looking forward to trying the EML tube, hopefully this will be here in the next few days.

[tdangelo]

can someone tell me what the power consumption is at low and high bias?  I'm thinking of getting these to replace my Acoustic Research Ref 210's.  I live in Florida and would like some cooler running amps that can be left on 24/7 - the 210's are wonderful but really heat up my room.  I'm hoping the 150's run fairly cool and draw low power in the low bias mode.  Any insite?
Thanks
Tony

[Marco Prozzo]

can someone tell me what the power consumption is at low and high bias?  I'm thinking of getting these to replace my Acoustic Research Ref 210's.  I live in Florida and would like some cooler running amps that can be left on 24/7 - the 210's are wonderful but really heat up my room.  I'm hoping the 150's run fairly cool and draw low power in the low bias mode.  Any insite?
Thanks
Tony

I can confirm that in low bias the KWA 150 does indeed run very cool.  I've never checked the power consumption, but I'm sure it is less (Dan could confirm that). In High Bias the amp does run hot.  In my system, and to my ears, I prefer the sound in high-bias. But at least one person has told me that for their system (which was fronted by big Maggies), they preferred the sound in the low-bias setting. 

Hope that helps.

[tdangelo]

Thanks Marco.  I guess it could be left on in low bias and then switched to high a bit before listening and then put back into low.  Can it be switched from low to high when turned on?

Tony

[Marco Prozzo]

Thanks Marco.  I guess it could be left on in low bias and then switched to high a bit before listening and then put back into low.  Can it be switched from low to high when turned on?

Tony

Yes; you can switch back and forth while the amp is on, so you could certainly do as you describe.  The bias switch is on the back of the amp.  I'll leave it to Dan to explain the differences in how the amp functions in each mode. 

[Philistine]

Thanks Marco.  I guess it could be left on in low bias and then switched to high a bit before listening and then put back into low.  Can it be switched from low to high when turned on?

Tony

Tony,
I have been leaving my KWA150 on 24/7 the last week, when not listening and at low 'background' levels I run it in low bias -and then switch to high bias for more critical listening.  Like Marco I prefer high bias and do switch bias modes on-the-fly (this is supported in the manual).
Phil

[Marco Prozzo]

Thanks Marco.  I guess it could be left on in low bias and then switched to high a bit before listening and then put back into low.  Can it be switched from low to high when turned on?

Tony

Tony,
I have been leaving my KWA150 on 24/7 the last week, when not listening and at low 'background' levels I run it in low bias -and then switch to high bias for more critical listening.  Like Marco I prefer high bias and do switch bias modes on-the-fly (this is supported in the manual).
Phil

Hey Phil - Have you formed any opinion as to whether this method is preferable for you, to leaving the amp in high-bias and turning it on and off from dead-cold each time you want to listen?  Does it reach its potential significantly faster from low-bias than it would from 'off'?

[Philistine]

Thanks Marco.  I guess it could be left on in low bias and then switched to high a bit before listening and then put back into low.  Can it be switched from low to high when turned on?

Tony

Tony,
I have been leaving my KWA150 on 24/7 the last week, when not listening and at low 'background' levels I run it in low bias -and then switch to high bias for more critical listening.  Like Marco I prefer high bias and do switch bias modes on-the-fly (this is supported in the manual).
Phil

Hey Phil - Have you formed any opinion as to whether this method is preferable for you, to leaving the amp in high-bias and turning it on and off from dead-cold each time you want to listen?  Does it reach its potential significantly faster from low-bias than it would from 'off'?

Marco, my previous amp was a Musical Fidelity that the then importer (Signal Path) told me performed better being left on overnight - they were correct when I tried it, but I never made 24/7 standard practice as the pre amp section was tubed based and my concern was tube life.  I believe the KWA sounds better being left on 24/7, the only caveat is that I only have my 36.5 in the system for a few weeks (so this needs to fully burn in) and I have a pair of Bybee'd tube adapters in place - so other variables as well are in place making it difficult to say categorical that it's beneficial.  I will probably try it again in a few weeks time when my system is constant - trouble is it's never constant  

[Marco Prozzo]

Marco, my previous amp was a Musical Fidelity that the then importer (Signal Path) told me performed better being left on overnight - they were correct when I tried it, but I never made 24/7 standard practice as the pre amp section was tubed based and my concern was tube life.  I believe the KWA sounds better being left on 24/7, the only caveat is that I only have my 36.5 in the system for a few weeks (so this needs to fully burn in) and I have a pair of Bybee'd tube adapters in place - so other variables as well are in place making it difficult to say categorical that it's beneficial.  I will probably try it again in a few weeks time when my system is constant - trouble is it's never constant

My experience over the years has been that the few SS class A amps that I've owned benefit greatly (as does the local power company) from being left on 24/7 and are actually better sounding after a day or two left on.  They also double as very inefficient space heaters, some of which might actually have served as a decent hot-plate (Pass Aleph's come to mind there).  I think the KWA is an A/AB design.  I haven't experimented much with leaving it on or in low-bias so was curious how others may have experienced this thus far.  In my rack it is a bit inconvenient with the amp in its current position to get around back to toggle the bias switch so I've just been turning it on and off from the front and leaving it in high-bias.

[Daedalus Audio]

Just some more kudos for the KW150! Received my pair last week and am continually blown away!  As mono blocks there is practically unlimited headroom and the sound is completely effortless, a clear window into the music and recording.  These amps are inspiring me to push some new speaker designs, thanks Dan for putting new life in this old horse...
Lou

[dmatt]

can someone tell me what the power consumption is at low and high bias?  I'm thinking of getting these to replace my Acoustic Research Ref 210's.  I live in Florida and would like some cooler running amps that can be left on 24/7 - the 210's are wonderful but really heat up my room.  I'm hoping the 150's run fairly cool and draw low power in the low bias mode.  Any insite?
Thanks
Tony

Tony,

Reading off my Furman SPR-20i, two KWA-150s draw 'between' 1.8 and 2.1 amps at low bias and between 6.9 and 7.4 amps at high bias.  So that's what, about 1 amp at low bias and 3.6 amps at high bias for one KWA-150?

The reason for the 'between' is that I took a reading at two different times, each time letting the amps idle for 60 minutes and I got two different readings.  No other equipment was on during the test.

Amps are slightly above room temp at low bias and warm at high bias.  Funny thing, they are warmer when idling at high bias than when cranking the tunes.

I leave them on 24/7 on low bias and flip to high bias for critical listening.  The current draw climbs from 2 amps to 7 amps in about 10-15 minutes.

Hope this helps.

David

[modwright]

The current draw numbers do look correct.  Some more numbers that will interest you includ the following:

THD + N at rated power of 150W into 8 ohms stereo and 250W into 4 ohms stereo = .05%!  Mono ratings nearly identical.

I will publish a full list of specs soon.

Thanks!

Dan

[silver700]

Hi Dan, I recently just heard about your KWA 150 and I am really impressed by the reviews (6moons) and looks of your new reference amp.  I just have a couple of quick questions, first I wondered why wattage is different for amplifiers, specifically the 150.  What I mean is that I was originally interested in a McIntosh mc402 which is rated at 2 X 400 watts, but now I am rethinking that approach and looking at the 150 and wondered if the KWA 150 is as powerful as the mc402.  Secondly, I know you are not here to knock the competition, but what would you say are some of the biggest advantages that the KWA 150 offers as opposed to other amps in its class specifically the mc402? I am really interested in your product and will try and get a listen, I just wanted some feedback as to why I should rethink my initial intention of buying the mc402.  Again, I am not trying to knock the McIntosh product, I just want to know, before I get a listen, what advantages the 150 has over other amps.  Again thanks for taking the time to answer my question.  I hope it is not stupid question to ask 

[modwright]

Hi, first of all, not a stupid question to ask at all.  If I am not mistaken, the MC402 uses an autoformer at the output and is hence 400W per channel into any load.  Our design is not autoformer coupled, so it is 150W into 8ohms, 250W into 4 ohms and can produce as much as 650W into 4ohms in bridged-mono, all at no more than .05% THD. Many amps are rated at their max power into 1% distortion.

Our design is completely dual mono with dual power transformers, power supplies, input and output stages, as though it were two monoblocks in one case.  It is a very high-current design and therefor can handle difficult low impedance speaker loads.

I have not heard the MC402 specifically, but am familiar in general with the McIntosh sound and I feel that I can safely say that our amp will produce a more resolving and dynamic presentation, while still retaining a musical sound.  The McIntosh produces a sound that is very nice and not fatiguing, as does ours.  Our design is unique however, in that its resolution and bandwidth are exceptional and its noise floor very low.  The result is a very mucial sound even at low levels.

In the end, it is a matter of personal preference, but I can say that our KWA 150 has already beat out the likes of Levinson, Krell, Audiaflight and Musical Fidelity in customer comparisons.

Please feel free to call me if you have any more questions.

The MC402 is a fine amp.  The KWA 150 is a unique, high-performance and high-value product that I am proud to put our name on.

Sincerely,

Dan Wright
360.247.6688

[mikel51]

I received my KWA 150 from Dan this week.  I haven't had time to really listen in depth but here are some obvious imporvements--

I replaced my BAT VK75SE power amp driving Von Schweikert VR5 SE Anniversary speakers with the KWA 150.  I am using a BAT VK31SE preamp, and my source is primarily a Modwright transporter.  I was happy with the BAT power amp--not particularly motivated to change, but was intrigued by Dan's power amp and was curious to see what solid state power would do for my system.

I immediately noticed a  dramatic increase in both bottom end power and in control across the frequency spectrum when I switched in the KWA 150.  The increase in bass power is dramatic, and the bass clearly has more detail than with the BAT power amp; there is probably more detail across the mid bass and mid range frequencies.  I am less sure what I can say about the top end with the KWA 150 in comparison to the BAT--but that is a good thing.  I find the top end to be pleasing--its been so long since I have listened to solid state in my system that I am not sure whether I can call the Modwright amp tube-like.  The KWA150 may have a bit more edge on female vocals and other top end frequencies than the BAT, but I will need to do a closer comparison between the two amps to really form an opinion.

I plan to spend a while (a few weeks?) listening to the KWA running the speakers solo, and then try to biamp with Dan's power amp on the bottom and the BAT on the top.  I know this will be better than running the BAT solo, but I am not sure if running the BAT on top will add anything to the KWA150's performance. 

[Philistine]

I received my KWA 150 from Dan this week.  I haven't had time to really listen in depth but here are some obvious imporvements--

I replaced my BAT VK75SE power amp driving Von Schweikert VR5 SE Anniversary speakers with the KWA 150.  I am using a BAT VK31SE preamp, and my source is primarily a Modwright transporter.  I was happy with the BAT power amp--not particularly motivated to change, but was intrigued by Dan's power amp and was curious to see what solid state power would do for my system.

I immediately noticed a  dramatic increase in both bottom end power and in control across the frequency spectrum when I switched in the KWA 150.  The increase in bass power is dramatic, and the bass clearly has more detail than with the BAT power amp; there is probably more detail across the mid bass and mid range frequencies.  I am less sure what I can say about the top end with the KWA 150 in comparison to the BAT--but that is a good thing.  I find the top end to be pleasing--its been so long since I have listened to solid state in my system that I am not sure whether I can call the Modwright amp tube-like.  The KWA150 may have a bit more edge on female vocals and other top end frequencies than the BAT, but I will need to do a closer comparison between the two amps to really form an opinion.

I plan to spend a while (a few weeks?) listening to the KWA running the speakers solo, and then try to biamp with Dan's power amp on the bottom and the BAT on the top.  I know this will be better than running the BAT solo, but I am not sure if running the BAT on top will add anything to the KWA150's performance.

Congratulations on the KWA 150, I've had mine over 6 months and have continue to appreciate it's capability to make great music as it goes from strength to strength.  I believe I had about 200 hours on it before it started to settle down and become smoother in the top end.

I too wanted to bi-amp with my old amp but found that the KWA outperformed it across the frequency range, I tried the KWA driving the woofers and then the mid range/tweeter.  Ultimately I concluded that the KWA alone was the best option in my system.  It will be interesting to get your feedback on how well the KWA and the BAT integrate.

[silver700]

Hi, first of all, not a stupid question to ask at all.  If I am not mistaken, the MC402 uses an autoformer at the output and is hence 400W per channel into any load.  Our design is not autoformer coupled, so it is 150W into 8ohms, 250W into 4 ohms and can produce as much as 650W into 4ohms in bridged-mono, all at no more than .05% THD. Many amps are rated at their max power into 1% distortion.

Our design is completely dual mono with dual power transformers, power supplies, input and output stages, as though it were two monoblocks in one case.  It is a very high-current design and therefor can handle difficult low impedance speaker loads.

I have not heard the MC402 specifically, but am familiar in general with the McIntosh sound and I feel that I can safely say that our amp will produce a more resolving and dynamic presentation, while still retaining a musical sound.  The McIntosh produces a sound that is very nice and not fatiguing, as does ours.  Our design is unique however, in that its resolution and bandwidth are exceptional and its noise floor very low.  The result is a very mucial sound even at low levels.

In the end, it is a matter of personal preference, but I can say that our KWA 150 has already beat out the likes of Levinson, Krell, Audiaflight and Musical Fidelity in customer comparisons.

Please feel free to call me if you have any more questions.

The MC402 is a fine amp.  The KWA 150 is a unique, high-performance and high-value product that I am proud to put our name on.

Sincerely,

Dan Wright
360.247.6688

Thanks so much for such a quick reply.  I have been reading up on the basics of amp in general and the prevailing opinion is that what you say is very true.  It is more about the current (or amps) than the wattage (I hope I said that right). I guess it is better to have a higher current amp with lower wattage rating than a lower current amp with a higher wattage rating? Do you feel, that in order to really hear what the 150 can do(as in 2 channel listening), it should be paired with either your 9.0 pre amp or the 36.5? I really want that openness, clarity, large sound stage, better bass from my speakers and wonder if that is possible by strictly upgrading my existing amp? I thought that upgrading the amp was the key, but after reading reviews about your wonderful amp, most reviews mention that the amp was paired with some type of tube pre amp. I just dont want to upgrade my amplifier only to be disappointed if the change or upgrade is minimal as far as sound quality.  I know that it all depends on my current setup, but as of right know I am using my ht pre-pro as my pre amp.  Again Dan, thank you so much for your help, and I just may give you a ring to get more info on your product.  I have to say, it really seems like a helluva product at that price point and I am anxious to get chance to listen to it.

[Rocket]

Hi Silver 500,

Can you tell us what your system comprises of so we can provide a little insight for you.

You stated that you are currently using a ht pre-pro as a preamplifier.  Is this the preamplifier that you intend to use?  Do you have an opportunity to listen to the amplifier in your system using one of Dan's dealers?

This is the best way to ascertain whether you will hear a difference.

Thanks

Rod

[modwright]

Regarding the high-frequencies, you will find that after 200-400 hours, the highs will smooth out and the bottom end will flesh out even further.  Our MWI capacitors are used in the signal path and PS decoupling in this amp as well as our preamps and the capacitors take time to break in fully.

One of the things that many of our customers comment on is that there is a bit of edge at upper frequencies initially that blends evenly over time as the capacitors break in.

I appreciate your posting your feedback.

Sincerely,


Dan W.