Hello All,
Can’t believe this is my first post…. Lurked around here long enough.
I’ve had my FW F6’s mono blocks up and running for six months or so, and they are great! Still amazed how quiet and detailed they are. The problem is, whenever I switch over to play heavier metal/rock, all sharpness is lost. Guitars lose their edge and everything gets soft/mushy. I’d really like to tighten this up. Before my questions, the following is my set-up:
Clearaudio Concept TT w/ Concept MM cartridge
Use the DAC in my Yamaha RX-A870 receiver for any digital/hi-res music
Parasound JC3+ phono preamp
Parasound JC2 BP preamp
KEF LS50 speakers (8 ohms)
I suspect the inefficiency of the LS50 is limiting the sharpness I’m seeking? Furthermore, I’m afraid that the LS50’s forte isn’t this type of music. Now to the questions I hope you all can give insight on:
1) Because I have an extra set of F6 boards/components on hand and plenty of power supply per mono block (8 x 18,000uf & 300VA transformer). Should I consider adding the extra boards to each mono block’s heat sink and revising to a balance mono/bridged connection? Especially since my preamp already supports balanced lines?
2) The way I’ve read in other threads and the F4 manual, a parallel mono set-up wouldn’t be much of a help for my scenario. Am I misunderstanding?
3) I’m mid process of building a Troel’s Prelude speaker (cabinet to copy the look of Focal Scala), and I’m afraid that the situation is only going to get worse with more demand from the speaker. (albeit with slightly better efficiency). Should I save the effort of trial and erroring and simply purchase or build a larger power amp?
Pictures attached for reference and any advice is greatly appreciated.
Regards,
Jason
Can’t believe this is my first post…. Lurked around here long enough.
I’ve had my FW F6’s mono blocks up and running for six months or so, and they are great! Still amazed how quiet and detailed they are. The problem is, whenever I switch over to play heavier metal/rock, all sharpness is lost. Guitars lose their edge and everything gets soft/mushy. I’d really like to tighten this up. Before my questions, the following is my set-up:
Clearaudio Concept TT w/ Concept MM cartridge
Use the DAC in my Yamaha RX-A870 receiver for any digital/hi-res music
Parasound JC3+ phono preamp
Parasound JC2 BP preamp
KEF LS50 speakers (8 ohms)
I suspect the inefficiency of the LS50 is limiting the sharpness I’m seeking? Furthermore, I’m afraid that the LS50’s forte isn’t this type of music. Now to the questions I hope you all can give insight on:
1) Because I have an extra set of F6 boards/components on hand and plenty of power supply per mono block (8 x 18,000uf & 300VA transformer). Should I consider adding the extra boards to each mono block’s heat sink and revising to a balance mono/bridged connection? Especially since my preamp already supports balanced lines?
2) The way I’ve read in other threads and the F4 manual, a parallel mono set-up wouldn’t be much of a help for my scenario. Am I misunderstanding?
3) I’m mid process of building a Troel’s Prelude speaker (cabinet to copy the look of Focal Scala), and I’m afraid that the situation is only going to get worse with more demand from the speaker. (albeit with slightly better efficiency). Should I save the effort of trial and erroring and simply purchase or build a larger power amp?
Pictures attached for reference and any advice is greatly appreciated.
Regards,
Jason
Attachments
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I am not sure about the F6, but your power is limited by the current set in the amp unless it can switch to class B, you are not gaining anything.
You will have to double the current if you are thinking to double the voltage swing by bridging it.
You will have to double the current if you are thinking to double the voltage swing by bridging it.
From Stereophile:
"Somewhat optimistically specified at 8 ohms, the LS50's impedance (fig.1, solid trace) drops to 4 ohms at 200Hz and to 5.4 ohms at the top of the audioband. The electrical phase angle is generally mild, but the combination of 5.3 ohms and –41° at 135Hz, a frequency where music often has high energy, will make the speaker work at its best with a good, 4 ohm–rated amplifier.
Read more at https://www.stereophile.com/content/kef-ls50-anniversary-model-loudspeaker-measurements#d4fci4qAPBVuOPXF.99"
If the f6 has enough volume for you what you need is more current into a low ohm load. This can achieved by bridging or increasing bias. Your heatsinks are a bit undersized (especially if they sit flat like that where they are less efficient) which means you are limited as to how hot you can bias the amp.
If you like the F6 design and want to continue with it I'd try another set of channels and bridge them.Or get more heatsink. But really, there are probably better amps for those speakers which are either Class A/B or Class A heavily biased with multiple outputs...like the F5 Turbo.
4 ohm loads and Class A means big heatsinks or fans, unfortunately. It is simply beyond the laws of physics to have the bias levels needed to stay in Class A at 4 ohms (or less) and dissipate the heat required by these bias levels in a small chassis.
Thanks Guys,
Definitely enough volume, so my thoughts were in the right direction with bridging. However, increasing the bias may be an easier window to see what is possible. It crossed my mind to do so, but didn't think I could really gain much from pushing the heat limits. Last thing I want to do is risk burning things up.
Heat sinks (300 x 165) run perpendicular to the floor like the 4U chassis and are mildly warm after an hour of solid use. So good there. Perhaps I'll try pushing the boundaries of bias a little bit and see if the condition improves. If they do, maybe I'll redesign the case for more heat sink and bridged layout.
If not, then it looks likes I'll have another build in my future...... No complaints of course.
Thanks Guys.
Definitely enough volume, so my thoughts were in the right direction with bridging. However, increasing the bias may be an easier window to see what is possible. It crossed my mind to do so, but didn't think I could really gain much from pushing the heat limits. Last thing I want to do is risk burning things up.
Heat sinks (300 x 165) run perpendicular to the floor like the 4U chassis and are mildly warm after an hour of solid use. So good there. Perhaps I'll try pushing the boundaries of bias a little bit and see if the condition improves. If they do, maybe I'll redesign the case for more heat sink and bridged layout.
If not, then it looks likes I'll have another build in my future...... No complaints of course.
Thanks Guys.
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Would those same metal/rock recordings sound great with another amp? The reason I ask is that the actual recording itself could be inferior. I’m not a metal person but perhaps high fidelity recordings aren’t a primary goal.
When I did my FW amp I couldn’t believe how incredible it sounded but it also revealed how poor many of my other music files were. Much of my older electronic music became unlistenable. It still sounds great in my truck but not out of my F5.
When I did my FW amp I couldn’t believe how incredible it sounded but it also revealed how poor many of my other music files were. Much of my older electronic music became unlistenable. It still sounds great in my truck but not out of my F5.
Playing directly through the power amp of the Yamaha yields decent results. Not as good as the F6 at lower volumes and complexity, but can deliver the goods once things get moving.
However, I heard you on the quality of metal recordings. Some are a plain mess!
I have KEF R700.
Ive heard ls50 before and like them a lot. But if you read a lot of reviews they are kind of on the “does not play well with lower powered amps list”. Which is common for a lot of small two way speakers. Kind of counterintuitive...little speaker needs big amp. But Something about the ls50 presentation feels very right...then seem very natural in presentation.
Frankly (my opinion though 🙂 Kent Engineering Foundry simply did not produce Any speakers worth their asking prices.
KEFs' entire history reads of constant trying to catch up/keep up with other makers, by using ill conceived 'advances', that weren't. ..ie; their UniQue Coaxes.. embarrassing things.
Audition some 'more capable' speakers ...you will be surprised at the difference.
KEFs' entire history reads of constant trying to catch up/keep up with other makers, by using ill conceived 'advances', that weren't. ..ie; their UniQue Coaxes.. embarrassing things.
Audition some 'more capable' speakers ...you will be surprised at the difference.
Ls50 is perhaps the most positively reviewed speaker of the last decade and was product of the year in many publications. If one is happy with a speaker of that size I don’t think you can do better...maybe at any price.
But everyone has their preferences.
Unfortunately when I started getting into this a couple years ago, I was sold on all the positive reviews of the Ls50. Coming from the guitar amp world, I thought to myself, how can 25 watts not drive the small little speaker properly??? Bad logic, I know.....
Although it does sound good, especially with a sub, I now know what is possible after going to Axpona this year in Chicago. Hence the start of the Troel's Prelude build. I have high hopes for it, and can't wait to hear and see it come together. Still think I'll need to upgrade the power amp to drive it though as it lies in the same impedance range of the ls50's.
Although it does sound good, especially with a sub, I now know what is possible after going to Axpona this year in Chicago. Hence the start of the Troel's Prelude build. I have high hopes for it, and can't wait to hear and see it come together. Still think I'll need to upgrade the power amp to drive it though as it lies in the same impedance range of the ls50's.
Hi Jason!
To your ideal if the F4 would drive it better:
2 mono blocks should be enough even for the hard to drive Kef 50s. (See the F4 owner's manual for the details.)
Generally if a First Watt amp is not "strong" enough for the speaker, then it's the wrong speaker. Of cause, this is just one perspective to the problem.
And you said you work on this with a speaker of Troels, the Prelude.
Just a nudge for changing the view on the speaker problem:
Do you also had a look at the Fusion? Troels said that it's one of the best speakers he's build. And the Fusion like other constructions have the option to use an dedicated build in amp for the bass section. This has two advantages: Your amp driving the speaker can be a Firstwatt amp, so a smaller one with high quality is more than enough, and the amp in general is freed of the burden driving bass, so it can shine with the midband and highs.
Regards, Matthias
To your ideal if the F4 would drive it better:
2 mono blocks should be enough even for the hard to drive Kef 50s. (See the F4 owner's manual for the details.)
Generally if a First Watt amp is not "strong" enough for the speaker, then it's the wrong speaker. Of cause, this is just one perspective to the problem.
And you said you work on this with a speaker of Troels, the Prelude.
Just a nudge for changing the view on the speaker problem:
Do you also had a look at the Fusion? Troels said that it's one of the best speakers he's build. And the Fusion like other constructions have the option to use an dedicated build in amp for the bass section. This has two advantages: Your amp driving the speaker can be a Firstwatt amp, so a smaller one with high quality is more than enough, and the amp in general is freed of the burden driving bass, so it can shine with the midband and highs.
Regards, Matthias
Thank You Matthias for the suggestion. I mulled over which design to build for months! The fusion design was in my top 3 picks, but the Prelude won out due to the WAF. I could easily make the Prelude in a Focal Scala skin with minor changes to the dimensions. Plus I wouldn't have to mess with the crossover by not moving the woofers around.
Knowing now that I'm shy on power, I would have been a little more persuasive with the Fusion design and integrated bass amp. Unfortunately I'm too far into the build and my wife doesn't have much of an eye for square/boxy speaker.
Luckily Mr. Gravesen is responsive to all emails, and confirmed that I'd be pleased with the outcome of the Prelude if I built as I've shown. He also confirmed that he'd build the same speaker today as it is without changing anything. So fingers crossed....
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Hi Jason,
since you are building the speaker yourself, it should be not that difficult to separate the crossover in a bass and a mid/high section, having two pairs of binding posts at the speaker.
Then you can biamp: one amp on the bass, one on the mid/high section. That is maybe the easiest and most flexible option to have more amp power and using the amp you already have. And you can use different types of amps for bass, resp. for mid/high, assigning the ones that best fit the respective task.
Best regards,
Claas
since you are building the speaker yourself, it should be not that difficult to separate the crossover in a bass and a mid/high section, having two pairs of binding posts at the speaker.
Then you can biamp: one amp on the bass, one on the mid/high section. That is maybe the easiest and most flexible option to have more amp power and using the amp you already have. And you can use different types of amps for bass, resp. for mid/high, assigning the ones that best fit the respective task.
Best regards,
Claas
Jason, there is something more important than WAF: The wife itself! She will be thankful for your compromise and for a fine craftsmanship and sound afterwards, and give this back to you...
Your design looks gorgeous!
Class tipp is great, it's easy as can be and you get all the flexibility. For the bass it's not that important which amp you use unless it can show its muscles if necessary and has got the same gain than the amp for mids/highs.
Troels has also an article of using a plate amp as separate amp, (you could use it in the future for a different project), but of course any other quality amp will do.
Please report back if you have finished your project!
Enjoy the way,
Matthias
Your design looks gorgeous!
Class tipp is great, it's easy as can be and you get all the flexibility. For the bass it's not that important which amp you use unless it can show its muscles if necessary and has got the same gain than the amp for mids/highs.
Troels has also an article of using a plate amp as separate amp, (you could use it in the future for a different project), but of course any other quality amp will do.
Please report back if you have finished your project!
Enjoy the way,
Matthias
Thank you for your kind words Matthias. The more I age, the more I want to create products that'll outlast me and hopefully look good for years to come. I will definitely report back when it's all together.
For now, I've thrown the full designs up on GrabCad for anyone to use. Mr. Pass shares his designs, so why shouldn't we all! There are a couple revisions on the way, but nothing affecting the layout.
3D CAD Model Collection | GrabCAD Community Library
Claas,
Definitely have the cross overs split up for bi-amping with separate binding posts and crossovers already. Just never thought I'd use them until now. Great idea, thank you.
Regards,
Jason
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