[megabigeye]

Hi AudioCirclers, and happy Patriot's Day!

You all seem like a friendlier and more helpful lot than at some other HiFi sites, so I'm looking forward to you being able to help me out.  My most recent system has consisted of a NuForce HDP working as preamp/DAC, Dayton DTA-100a, JohnBlue JB3 speakers, and BIC V1020 sub.  The DTA-100a recently bit the dust.  I also used to have a KingRex T20 which also died.  I really enjoyed the sound of the Dayton (and the KingRex, but I didn't get to use it nearly as much) in my system, especially for the price, but I'd really like a step up in build quality and reliability.  I also figure I really wouldn't mind a step up in sound as well.

My price limit is about $500USD and I think I'm more interested in power amps than I am in integrateds, simply for the simplification of how many volume pots I and my girlfriend have to fiddle with.  Though there are also a few integrateds I'm interested in if I can be convinced of their superiority.  In other words, I'm not really sold one way or the other, but simpler seems like it would be nicer.
I also should mention that the input limit on the JB3s is only 30W, and I'm a little worried that too much power is going to fry them.  I know some people disagree, but I remain uncertain (convince me!).  One last constraint is that I don't have a huge amount of space.

So here's what I've been looking at so far (in no particular order)...
Topping TP60.
I think I'm mostly interested in this one because it's inexpensive and has those two pretty toroids.  And it's Class-T.  Though I'm wary of it because it seems like it could be of questionable reliability/quality.  I'd really rather not have to replace it again in two years.  I'm also a little skeptical of connecting a T-Class amp to a sub via speaker level, since allegedly it can short the amp.

Virtue One.3
The earlier Virtues really piqued my interest a few years ago, but they were a bit out of my price range on my last couple of go-rounds.  I'll assume that the sound and build qualities are a step up from my Dayton, but are they really worth more than four times the cost (5.5 times the cost with upgraded PSU)?  It has a sub output, which I like the looks of, but the high pass filter is only set at 80hz.  I keep my crossover set at about 110hz, I think.  Would that be a problem?  Also, reliability?

Emotiva UPA-200
Class A/B is something I'm not so familiar with and I'm uncertain if I'd like it.  Which isn't to say that it's something that I wouldn't be able to get used to.  Also, would that amount of power fry my dainty little speakers?  Further more, the volume control on the HDP isn't the best and I'd be afraid that too much power wouldn't give me much wiggle room for finding a comfortable level.  Also, physical size might be a bit of a problem, though I might be able to figure something out.  The price sure is right, though.

NuForce STA-100
The price is probably too high on this one.  I might be able to swing it if somebody convinced me that it's absolutely the best choice.  Also, the power issue has me slightly worried.  Otherwise I really like the looks of it (literally.  I really love the way it looks.).

Parasound Zamp
The price is right.  The power is right.  The size it right.  It gets stellar reviews from professionals.  For some reason there is very little user feedback about this amp.  Also, it's Class A/B.  And it's name sounds dumb (or cute, I guess).  I also think this is something that I could potentially audition and buy locally.

NAD D 3020
This is a strange and intriguing option.  If I went with something like this I could forgo the HDP altogether, although I really enjoy its sound and headphone capability.  I know NAD makes quality pieces, but I'm a little skeptical that so many features at so low a price means lowered quality throughout.  I'd be willing to bet I could find this locally, too.

Please, please, please help me make a decision!  Also, if there are any other great options that I'm missing, I'd appreciate knowing about them (so that I can further confuse myself).  Also, this whole post is sort of posed as a question; if I've got anything wrong, please don't hesitate to correct me.

...And thanks in advance for any input you have!! (and apologies for such a long-winded first post)

[JLM]

Welcome aboard!

Do you need analog inputs or headphone outputs in your system? 

When amps are pushed too hard (wattage/low impedance) they distort.  One of the basic forms of distortion in called clipping.  If you think of a sine wave (smooth wave form seen on oscilloscopes) the height of the wave represents the peaks (tops and bottoms) of the signal.  Sound (music) is nothing more than a collection of pressure waves shaped like sine waves.  In the case of a loudspeaker it is caused by the in and out movement of the driver(s) that copy that collection of sine waves as driven by the amp.  So the amp creates sine waves.  When the amp is forced beyond it's distortion free limit the tops and bottoms of the signal are clipped off (suddenly flattened).  Note that tube amps (and some solid state like NAD) "soft" clip (round off the edges of the clip) which helps the speaker handle the clip.  The loudspeaker is trying to copy the signal and has to make an instant stop/start which produced heat (the energy has no other place to go).  This melts the driver voice coils.  This is the danger of undersized amps.

As a collection of sine waves music has dynamic peaks (that can require 10 - 400 times the average power being used) but only sound 2 - 5 times as loud (the difference is due to the logarithmic  relationship between power and sound).  Oversized amps can fry drivers but it's easier because of this power/sound relationship and the instantaneous nature of the musical peaks to damage speakers from too little rather than too much power.  I'm of the opinion that you want to size the amp to maintain a commending grip on the speaker (because of this clean/clipped power issue and to improve overall sonic resolution), so I use 100 watts for my speakers rated 27 watts continuous/80 watts peaks.  Keep in mind that during hard partying all bets are off.

The logarithmic relationship of amps means 1 watt = 0 dB of gain, 2 watts = 3 dB of gain, 4 watts = 6 dB of gain, 5 watts = 7 dB of gain, 8 watts = 9 dB of gain, 10 watts = 10 dB of gain, 20 watts = 13 dB of gain, 40 watts = 16 dB of gain, 100 watts = 20 dB of gain, 1,000 watts = 30 dB of gain.  Note that 3 dB produces a 'half again' louder sound.  So 20 watts versus 40 watts isn't a huge difference to your speakers or you.  With speakers rated at 30 watts, I'd shop for 20 - 50 watts.

Another small/quality amp in your wattage/price range is the TBI amp (see the low wattage circle below).

[Nick77]

These class d amps created quite a stir over the past several years as being a great bang for the buck. Might even be one in classifieds for cheap. They were only diy but started making them in completed cases also.

http://www.audiocircle.com/index.php?topic=76400.0

[JCS]

Because you want to use a sub, I would recommend staying with a pre-amp.  Split the pre-amp's output to the power amp (or integrated) and sub.  Or buy an integrated that has pre-outs.  Then you don't need to worry about the amp being common ground, which is essential if you connect the sub using speaker level inputs.  If the amp isn't common ground & you connect with speaker level inputs, it may have a rather short life.  As far as I know, T-amps are not common ground & should never be connected to the sub's speaker level inputs.  Now you can connect an amp's speaker level output to a sub's line level inputs if you have a special cable that converts the speaker level outputs to a line level input, but that's a tale for another day.

Cheers,  Jim

[charmerci]

Because you want to use a sub, I would recommend staying with a pre-amp.  Split the pre-amp's output to the power amp and sub.

How does one do that?

[Sparky14]

Virtue One.3
The earlier Virtues really piqued my interest a few years ago, but they were a bit out of my price range on my last couple of go-rounds.  I'll assume that the sound and build qualities are a step up from my Dayton, but are they really worth more than four times the cost (5.5 times the cost with upgraded PSU)?  It has a sub output, which I like the looks of, but the high pass filter is only set at 80hz.  I keep my crossover set at about 110hz, I think.  Would that be a problem?  Also, reliability?

Emotiva UPA-200
Class A/B is something I'm not so familiar with and I'm uncertain if I'd like it.  Which isn't to say that it's something that I wouldn't be able to get used to.  Also, would that amount of power fry my dainty little speakers?  Further more, the volume control on the HDP isn't the best and I'd be afraid that too much power wouldn't give me much wiggle room for finding a comfortable level.  Also, physical size might be a bit of a problem, though I might be able to figure something out.  The price sure is right, though.

I can give you feedback on the UPA-200/Virtue/DTA-100a. I have had the UPA-200, and Virtue Sensation and two.2 amps, and have the DTA-100 in my office system.

The UPA-200 is a nice budget amp, but I do think that is too much power if you have sensitive speakers.

The Virtue amps do sound great for the money. My current setup has the two.2, using the 80Hz bypass to feed a powered sub. The two.2 has plenty of power for my fairly insensitive 4-ohm speakers, so you should be fine there. I do have an upgraded power supply for the two.2, and I will say that the difference between the stock and upgraded supply is not that significant when using the sub output. I think using the Virtue full range would benefit from the upgraded power supply. But with an external sub, and sensitive speakers, I wouldn't automatically opt for an upgraded power supply at this time. You can always add one later. And yes, the Virtue amps are definitely worth the upgrade from the DTA-100a.

You might look for used options on Virtue amps. With the one.3s out, there may be used one.2 and two.2s on the market.

[geowak]

I would like to suggest some other choice you could make. Find an older Marantz receiver. You could find one in good to minty shape. Like the 2230, 2240, 2270 or 2280 series. Great build quality and great power!! I have mint 2235, and it would drive your speakers beautifully.
There are a few 2250's on Ebay that are around your budget.

[jarcher]

My vote roughly in this order would be :

1. NAD D3020
2. Marantz PM 6004 ($350 @ accessories4less)
3. Teac AH-01 ($250 @ accessories4less)

Only digital inputs :

1. NuForce DDA-100 (demo for sale $483 @ audio advisor)
2. Wadia 151 power DAC ($500 @ music direct)

In the sub $500 range the NAD seems to be the one to beat.

[megabigeye]

Wow!  What a great welcome!  I was hoping for just one or two replies over the course of a couple of day, so this is great!

JLM,
I've read about some of that before, but you've got a very succinct and clear way of phrasing things.  Very helpful.  So do you think I could get away with more power (like 100W+ , like the Emotiva and NuForce offer, or even 80W like the Virtue), or do you think I should stick closer to the 20W-50W range?  I'll have to look more into that TBI amp, as well.  Very attractive.

And yes, I need analog inputs, as I have a turntable too.  I'd like to keep a headphone out as an option, though I don't use my headphones as much as I used to.  I guess it wouldn't kill me if there was an otherwise great amp that didn't have a headphone stage.

Thanks again for your input!

[megabigeye]

These class d amps created quite a stir over the past several years as being a great bang for the buck. Might even be one in classifieds for cheap. They were only diy but started making them in completed cases also.

http://www.audiocircle.com/index.php?topic=76400.0

Yeah, I saw that thread and I am a bit intrigued by DIY, but also a little afraid of it...  Though I guess the ready made ones aren't technically DIY.  How is the quality?

I think I also saw that you had a couple of them up for sale, didn't you?

I also had my eye on some TK2050 boards from Sure and HiFiMeDIY.  Again intriguing, but I imagine myself getting it, hooking it up just to "test" it and then never putting it in a case.  I have a CMoyBB, completely unassembled, that's been sitting on my desk since Christmas.  Maybe one day, but I don't think this is the day.

[megabigeye]

Because you want to use a sub, I would recommend staying with a pre-amp.  Split the pre-amp's output to the power amp (or integrated) and sub.

Yeah, this is what I was thinking and that's actually how NuForce recommends hooking up a sub to the HDP.

Or buy an integrated that has pre-outs.  Then you don't need to worry about the amp being common ground, which is essential if you connect the sub using speaker level inputs.  If the amp isn't common ground & you connect with speaker level inputs, it may have a rather short life.  As far as I know, T-amps are not common ground & should never be connected to the sub's speaker level inputs.

I had the DTA-100a hooked up at speaker level which I read you weren't supposed to do, but it seemed to work so I did it.  I figured if it was going to short the amp that it would be sudden.  Do you think this could have caused a slow death?

Now you can connect an amp's speaker level output to a sub's line level inputs if you have a special cable that converts the speaker level outputs to a line level input, but that's a tale for another day.

Cheers,  Jim

Do you just need a cable something like this?  That seems simple enough.

[megabigeye]

I can give you feedback on the UPA-200/Virtue/DTA-100a. I have had the UPA-200, and Virtue Sensation and two.2 amps, and have the DTA-100 in my office system.

The UPA-200 is a nice budget amp, but I do think that is too much power if you have sensitive speakers.

Can you quantify "sensitive?"  The JB3s are rated as 87dB/W/m.  I wouldn't have thought that was particularly sensitive, but what do I know?

The Virtue amps do sound great for the money. My current setup has the two.2, using the 80Hz bypass to feed a powered sub. The two.2 has plenty of power for my fairly insensitive 4-ohm speakers, so you should be fine there. I do have an upgraded power supply for the two.2, and I will say that the difference between the stock and upgraded supply is not that significant when using the sub output. I think using the Virtue full range would benefit from the upgraded power supply. But with an external sub, and sensitive speakers, I wouldn't automatically opt for an upgraded power supply at this time. You can always add one later. And yes, the Virtue amps are definitely worth the upgrade from the DTA-100a.

Does the sub-out only do 80hz and below?  'Cause that wouldn't work for me.  I know there are mods to change the high pass filter, but...  Yikes.  I'd be scared I'd fry something.
Do you think it would work with a preamp like my HDP?  With the One.3 or one of the previous models I could just leave the volume up when I power on/off.  I don't know if that's ideal since it has a preamp stage.  The One.3 is tempting if a pre works.

You might look for used options on Virtue amps. With the one.3s out, there may be used one.2 and two.2s on the market.

I've looked a little (here, AudioGon, ebay, head-fi).  Nothing yet.

[megabigeye]

My vote roughly in this order would be :

1. NAD D3020
2. Marantz PM 6004 ($350 @ accessories4less)
3. Teac AH-01 ($250 @ accessories4less)

Only digital inputs :

1. NuForce DDA-100 (demo for sale $483 @ audio advisor)
2. Wadia 151 power DAC ($500 @ music direct)

In the sub $500 range the NAD seems to be the one to beat.

Yeah, I just saw the NAD last night before I posted, so I didn't have much time to research it.  If it's as great as you say I'll have to look more.
I also remember reading about the Marantz (or maybe it was the PM5004?) a while ago and thinking it looked impressive.  I'll revisit that one, too.
The Teac looks okay, but seems like the NAD just one-ups it for a similar price.
And I'd need an analog input, so the NuForce and Wadia are out of the picture.

I would like to suggest some other choice you could make. Find an older Marantz receiver. You could find one in good to minty shape. Like the 2230, 2240, 2270 or 2280 series. Great build quality and great power!! I have mint 2235, and it would drive your speakers beautifully.
There are a few 2250's on Ebay that are around your budget.

(I wish I'd realized I could multi-quote before!  Whoops!)
Those things are huge and gorgeous!  And huge!  I don't think I have enough room for that, plus I'd like to stay away from the vintage route and the can of worms it opens up.  Too many more options!

Ugh.  I'm feeling a bit reply-happy, so I think this will be my last post for the night.  Thanks again to everybody for all of your help, friendliness and replies!  Sincerely!

[JLM]

100 watts per channel is probably overkill for the JB3's.  For your system I'd invest more into quality rather than quantity. 

The other half of the wattage/dB equation to keep in mind is how loud you actually listen.  As a happy owner of JB3's I doubt you're a headbanger.  As a lover of single driver designs myself, I've found most are used for small ensemble stuff, not heavy/bombastic genres.  And because of my love (which traditionally correlates towards small tube amps, I also own a sound pressure meter as that camp fixates on wattage/efficiency.  What I've found is that most audiophiles over estimate the average dB they listen to but under estimate the peaks.  At most audiofests the rooms are running roughly 75 - 85 dB, which is too loud to comfortably carry on a conversation and if constant could cost your lease. 

So 80 dB with JB3 in an "average" room represents about 0.1 watts and you probably are listening at lower levels than that, which explains the old audio adage that "If the first watt sucks, why continue".  OTOH 30 watts would be around 102 dB.  The difference is 22 dB (quite workable).  Music peaks are 25 dB for symphonic and 10 dB (which sounds twice as loud) for jazz/rock above 'average'.  But the peaks are 105 dB for symphonic and jazz versus 110 dB for rock, so (surprise) the JB3's aren't the final solution for full/accurate musical reproduction of all musical types.

[Nick77]

Yeah, I saw that thread and I am a bit intrigued by DIY, but also a little afraid of it...  Though I guess the ready made ones aren't technically DIY.  How is the quality?

I think I also saw that you had a couple of them up for sale, didn't you?

I also had my eye on some TK2050 boards from Sure and HiFiMeDIY.  Again intriguing, but I imagine myself getting it, hooking it up just to "test" it and then never putting it in a case.  I have a CMoyBB, completely unassembled, that's been sitting on my desk since Christmas.  Maybe one day, but I don't think this is the day.

The quality for sub $500 amplifier is off the charts as 180 page thread attests. I have a diy version slightly modded with better quality power supply caps and increased capacitance which took it up several more notches. A lot of guys replaced some expensive amps with these diy modules, for me the strong point is resolution. Mine isnt for sale, but if it was it would be to move up to the class d Ncore amps. Good luck with the search, if you are in Austin you can take it for a spin in your system.

[JCS]

<<<I had the DTA-100a hooked up at speaker level which I read you weren't supposed to do, but it seemed to work so I did it.  I figured if it was going to short the amp that it would be sudden.  Do you think this could have caused a slow death?>>>

Hard to tell w/o a postmortem, however,  if I had to bet money on it: I would guess that the speaker level connection to the sub was a significant factor in the amp's short life.

As for the cable: NO, NO, NO!!!!  All that cable will do is blow up both the amp & the sub. You need a special cable which uses resistors to isolate & reduce the high signal levels on all the connections. In a class T amp, I have been told that both positive and negative leads are 'hot'.

Cheers,  Jim

[RDavidson]

I wouldn't hesitate to get a Virtue amp if it suits your requirements. Seth, Jason T, and crew are amazing people who truly care that you are happy with your purchase. Service after the sale is through the roof excellent.

But, given your speakers, I'd be inclined to give one of these a try via Amazon also. This amp has rceived pretty much universal praise, if you don't need a lot of power (and don't need a bunch of inputs/outputs)......and even then, apparently this little amp has more guts than the specs indicate. We all know Amazon has a liberal return policy, which is nice too.
http://www.amazon.com/APPJ-PA0901A-6P14-Amplifier-Silver/dp/B00APC0VXY

[milford3]

Look at the Musical Paradise MP 301-MK3.  It's under $400.00


http://www.musicalparadise.ca/store/index.php?route=product/product&path=59&product_id=54

[acresm22]

And just to muddy the waters with another suggestion, you might want to look at Clones Audio...they make a power amp version of their highly regarded 25i integrated. Both try to replicate the original 47Labs Gaincard as closely as possible, hence the company name. Been getting great press...

http://www.clonesaudio.com/#!amp/clj5

[megabigeye]

<<<I had the DTA-100a hooked up at speaker level which I read you weren't supposed to do, but it seemed to work so I did it.  I figured if it was going to short the amp that it would be sudden.  Do you think this could have caused a slow death?>>>

Hard to tell w/o a postmortem, however,  if I had to bet money on it: I would guess that the speaker level connection to the sub was a significant factor in the amp's short life.

Yeah, this was sort of my intuition.  That and overall poor quality.  I don't know if you've ever seen those old pictures of the internals of the DTA-100, but mine is actually worse.

As for the cable: NO, NO, NO!!!!  All that cable will do is blow up both the amp & the sub. You need a special cable which uses resistors to isolate & reduce the high signal levels on all the connections. In a class T amp, I have been told that both positive and negative leads are 'hot'.

Cheers,  Jim

Don't worry, I wasn't going to do anything drastic.  I just wanted to make sure I wasn't missing something simple.