Sorry - I took this forum off topic.
Sonically, a MOSFET amp would be miles above the Rotel.
1980's digital recordings were not good.
I think the reason was linearity issues with the ADC's.
Laser trimming improved the linearity issue.
So circa 1990 digital recording equipment improved.
To answer to your question - more info is needed about your speakers.
Specifically - about their impedance.
To select an amp - the speaker impedance should be known.
Before making your own speakers, you may want to browse through Troels Gravensen's website.
DIY Loudspeaker Projects Troels Gravesen
I'd suggest a 3 way design from Scan Speak and Seas.
Note how they stay above Z >= |5| ohms.
Crossover components can get quite expensive.
but the crossover is the soul of a speaker
So suggest picking a speaker with a minimum number of crossover components.
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I must admit I only built the F5 (Basic) as a sonic experiment.
My B-I-L built the Aleph 4 as a full Gun Ship with a massive 500VA x 2 PSU with huge 400000uF (yes nearly 0.5F) of supply caps.
I'm surprised by the comments about the B&W crossovers. My 603s3's had Mundorf Caps which I assumed were good. They've gone now to be replaced by the ODD yellow 802D's. They're away being De-Yellowed at a cabinet refinisher. I'm surprised that with an £11000 price tag B&W have taken £100 corners with componets.
My B-I-L built the Aleph 4 as a full Gun Ship with a massive 500VA x 2 PSU with huge 400000uF (yes nearly 0.5F) of supply caps.
I'm surprised by the comments about the B&W crossovers. My 603s3's had Mundorf Caps which I assumed were good. They've gone now to be replaced by the ODD yellow 802D's. They're away being De-Yellowed at a cabinet refinisher. I'm surprised that with an £11000 price tag B&W have taken £100 corners with componets.
Fancy crossover parts is a relatively new phenomenon from what i understand. Over the years, the selection of Primo parts has grown. This is either a result of results or marketing, or perhaps a little of both. I must admit I have heard differences, but would not recommend cap switching until you are sure that your current whatever is the your final whatever, as it will get expensive quickly. I chuckle when i see NElson using Panasonic in the signal path of some of his amps receiving highly praised reviews. Small lesson in that i believe.
B&W actually use the term "Specially selected components" in their sales info.
At the 802D level, I seriously doubt that you can make any improvement to what has been tested and proven.
Someone is going to come in and say that they have improved the Nautilus itself - a mere bargain at £32000 a pair.
I'm going to be looking after a pair next month only because the owner cant get insurance for them while he is globe trotting - NIRVANA.
At the 802D level, I seriously doubt that you can make any improvement to what has been tested and proven.
Someone is going to come in and say that they have improved the Nautilus itself - a mere bargain at £32000 a pair.
I'm going to be looking after a pair next month only because the owner cant get insurance for them while he is globe trotting - NIRVANA.
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Relevant to this thread. The DIY amps I am looking at are the Pass MOSFET low power class A designs vs. larger more conventional Pass designed amps. A bit bigger, but not much ( 60 to 100W), some requiring modifications ( GFS 535 maybe) and some not ( PA-5 I would hope)
Take a deep breath, I know I am in MOSFET land. I am not sure MOSFETs are miles ahead as a categorical statement. I own both. I have learned so much about amp design ( like .1% of what the real experts know) to know that there is way more to it than that.
The Rotels have an advantage in they MASK some problems typical of mid-range speakers. I never put them up as truly revealing high end. If you have something like Paradigm Studio 20's (I do) , then they do wonders in masking the tweeter breakup and distortion. My Modified Hafler, Parasound, B&K, and Creek are all more revealing if the speaker quality is sufficient. I consider that good engineering on Rotel's part. Design for the intended use. Their intended use is different than the F5.
For sure, the original Sony 14 bit mastered CD's were poor and are the cause for a lot of the bias against digital. A lot of new music is done in basements with A2D no better than my Behringer. Good source has always been a problem. Bad CD's are probably half my collection. Of the good half, half of them are poor recordings on analog before being digitally remastered. Such is life. Great classical guitar seems to usually be a bad recording.
My current project speakers are very similar to the Zaph SR71. I use the metal dome version of the tweeter and some differences in the box, but wound up with the identical crossover when I was done. They don't go below 6 Ohms. I can't measure absolute SPL because my mike is calibrated to difference, not absolute and I don't have a 100 foot chamber anyway. My simulation leaves them at about 87dB.
It comes down to for this application, in my small office, listening at quite reasonable levels, crossed-over with a sub, (electronic, 2 way, not just a helper) would a 25W class A DIY amp have sufficient power for my speaker, or should I stay with a 100W traditional amp? I know for sure, my 60W Hafler and Rotel do just fine power wise, my 6W tube does not. My 12 might, but it is so poor it was hard to tell if it was the 40 year old caps or running out of oomph. Pushing 50W class A is more than my air conditioning can handle. So, I have set bounds on my requirements.
one can ALLWAYS make improvements. B&W (or any other) has not developed the products for your room, your eletronics and your ears
NO ONE has. That is why the whole topic is so subjective.
has no one made improvements on a speaker???
i know plenty. on B&W, DALI, troels designs+++
I think he means no one has figured out how to design speakers for YOUR room. They have to design for everybody's room I can design speakers for MY room. Long live DIY. Have speakers improved? Vastly, but they are still the weakest link in the chain.
Still reading the F5T threads. I have not priced out the BOM.
Still reading the F5T threads. I have not priced out the BOM.
If you listen to classical - with metal dome tweeters - I highly recommend using Mundorf M-Cap Supremes in series with the tweeters.
Also, suggest using OCC solid core copper wire with teflon insulation.
I used 20 awg with a B&W tweeter with great success.
Replace commercial grade wire wound resistors - with metal oxide resistors will soften up those metal domes too.
other suggestions
JS Bach - Transcriptions
Goran Sollscher
DG 435 471-2
this may be discontinued - but try to find a copy
S.L. Weiss
Sonatas for Lute
Franklin Lei
Naxos 8.550470
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On B&W's website they used to have good tech articals - unfortunately, they have been removed.
But attached is one, where they explain bi wiring.
One of the FAQ's was - could the existing caps be replaced with higher quality caps ?
B&W said not to do this because all the properties of the cap had been designed into the crossover.
What absolute rubbish.
B&W's, like any product, are built to a price point.
In the 1990's, the 600 series and Nautilus used Bennic resistors and caps.
So here they are, with the Beautiful FST mid range driver and Nautilus tweeter,
and the beautiful Nautilus cabinets
using Bennic resistors and caps.
It certainly would be interesting to see if signature series, have far better crossover components, than the original Nautilus series.
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Always looking for good recording leads, thanks.
The current set I am building is the first time I have gone above Dayton film caps. This xover has a Clarity cap in the tweeter. The speakers are good enough, it may well be worth trying other caps. When using $20 tweeters, $50 caps make no sense. When using $50 tweeters, it may well change the rules.
I just don't think film at 10W or so. I really should. Again, thanks.
As B&W is a big business, and they do have real research, I suspect they have allowed for, to as you do say, for the price point, compensated as best they could for the parts they chose. For their prestige, the last thing they would want is some DIY thread saying how you could improve their sound by changing a cap. That would be a disaster for their marketing.
Everything they publish is marketing. The above "tech" article is absolute rubbish playing into the press and dealer profits. I am not beating them up. They make nice products for fair prices and have to stay in business.
We have to separate "Madison Avenue" engineering from the real thing. They make it up, we filter it out.
I checked the JSB Transcriptions disk.
Great music - great performance - sounds like 1990's Sony recording equipment.
Its a good recording.
From the literature available, it seems sometime circa 1990, Sony introduced 20 bit recording technology.
I also just re-checked the SL Weiss disk.
Unfortunately, the recording has a touch of harshness.
But of all the Weiss disks I have, this is the one I play all the time.
I have no experience with Clarity Caps or the Daytons.
Its the original AuriCap and Mundorf MKP and M-Cap Supremes I know.
For a digital source and metal dome tweeters,
the M-Cap Supreme has just the right balance between resolution and warmth to mask digital glare.
This cap moves the sonics very forward.
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Price does not matter at all, quality does. It often does not make a real price difference to produce fine stuff or mediocre stuff.
It all gets to numbers. If you are a producer of OEM parts you don't want the company that buys your stuff to have quality issues with its customers, especially if it buys large numbers.
Jean-paul,
I think you missed my point. Although price does not define quality, if you look at the performance you get for a very good $20 tweeter and the performance from a very good $50 tweeter, there is a huge difference. I full will grant you, there are $100 tweeters that are junk, and some of the $20 are pretty good. Retail, not OEM, cost I am talking. If a lot of people knew what these things sell for in 1000 lots, they would turn green.
I think you missed my point. Although price does not define quality, if you look at the performance you get for a very good $20 tweeter and the performance from a very good $50 tweeter, there is a huge difference. I full will grant you, there are $100 tweeters that are junk, and some of the $20 are pretty good. Retail, not OEM, cost I am talking. If a lot of people knew what these things sell for in 1000 lots, they would turn green.
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