John Curl's Blowtorch preamplifier part III

Status
Not open for further replies.
Jump to Latest
#2,821
The Met-7 on first appearance is not significantly different to many modern 'three-in-one' speakers, and some Bose speaker models also.
The above mentioned are typically wired with the woofer full range and a single series cap supplying the tweeter.
What is the crossover arrangement in the Met-7 ?.

Dan.
 
#2,822
Max Headroom said:
What is the crossover arrangement in the Met-7 ?.

Dan.
Click to expand...

Same, the drivers are custom and have what looks like wooden phase plugs. Electronics lends itself to rote precision the actual producing of the sound field from a simple two source setup remains a simulacrum and anything is fair.

I won a pair of bookshelf speakers (<$600) at a company event and I had not shopped for speakers for 15 or more years (family and kids). I asked the store to play me blind a few choices. Number one OK the BBC announcer sound, correct KEF. Number two the west coast in your face rock sound, correct JBL. Number 3 my old friend the polite east coast sound, correct again Snell.
 
#2,823
I'm only on my 3rd pair of hifi speakers ever. Pair 2 are still in use and are time aligned in a similar style to the Mets (infinity modulus). They have their compromises and fail pretty much all of Richard's requirements. But in a small room they disappear in a way I have only heard LS3/5a do. I will trade certain traits of accuracy for the ability to close my eyes and not be able to work out where the speakers are.

When I was auditioning these the ATC SCM20 were just out. I loved the big actives so listened to them. They were impressive in many ways but did odd things with the vertical plane and did not vanish. Their younger brothers the SCM10 did but by then it was too late. ATCs are marmite, but I still love the big studio monitors. If I win the lottery the media room will have soffit mount SCMs 🙂
 
#2,824
billshurv said:
Back on speakers, has anyone other than Jan heard the Kii3 yet? Just mulling over the speaker discussions and thinking about compromises. I have neither space nor money for the M2s, I could have just afforded the smaller Gedlees had I been in the market when they were in production but for many in smaller houses the Kii might just be the optimum, if a bit pricey at $11500 and anti audiophile as you can't get in an fiddle with things.

If you are compromised further then where should you not compromise? If it's directivity then the synergy clones being done on here might just be the best thing for DIY in years.
Click to expand...



Jan and I did a review of the kii for AudioXpress. I had them in my living room for an extended period and they are good, but a pair of semi-omni's had better imaging. These where the Kii2 I guess.
 
#2,827
Those JBL monitors mostly likely do use DSP and class D amps. That means they have A/D converters inside for use if the analog input is used. Maybe the D/A is done directly by the class-D amp, don't know. Otherwise they have D/A inside. That type of thing is becoming more and more common. I don't see how the SQ can be all that good if the whole thing costs $2k. A really good 2-channel DAC costs that much.

Just found some specs:
ELECTRICAL DISTORTION CRITERIA: 0.1%THD @ 1kHz/2.83VRMS output;
<0.5% THD @ 1kHz, Full rated output
SIGNAL TO NOISE RATION, HF: 92dBA (A-Weighted), 83dBr (unweighted),
relative to 2.83VRMS output on HF
SIGNAL TO NOISE RATIO, LF: 85dBA (A-Weighted), 80dBr (unweighted),
relative to 2.83VRMS output on LF
 
Last edited:
#2,836
Mark Johnson said:
And that's why my current project uses an AD744 + HA-5002: to make sure the opamp sees a negligible, high impedance "load", and to make sure the 600 ohm "true output load" is driven by a special high current beast with enormous safety margin. Plus, I once interviewed for a job at Harris and found their D.I. process to be wildly intriguing.
Click to expand...

scott wurcer said:
I hope you will share your results, the 744 had enough internal nodes brought out that you can challenge some pretty good discrete designs with minimal parts. You can bypass the output stage entirely or simply add an external PNP with no added bias components.
Click to expand...

It's now released, over in the Pass Labs forum. The circuit is called "Norwood", the city name on the datasheet of the Analog Devices AD744. You gotta open up the .zip archive file and hunt for the files inside whose names include the word Norwood.

View the attachment to post #1 of this thread: The diyAudio First Watt M2x
 
#2,838
Markw4 said:
Those JBL monitors mostly likely do use DSP and class D amps. That means they have A/D converters inside for use if the analog input is used. Maybe the D/A is done directly by the class-D amp, don't know. Otherwise they have D/A inside. That type of thing is becoming more and more common. I don't see how the SQ can be all that good if the whole thing costs $2k. A really good 2-channel DAC costs that much.

Just found some specs:
ELECTRICAL DISTORTION CRITERIA: 0.1%THD @ 1kHz/2.83VRMS output;
<0.5% THD @ 1kHz, Full rated output
SIGNAL TO NOISE RATION, HF: 92dBA (A-Weighted), 83dBr (unweighted),
relative to 2.83VRMS output on HF
SIGNAL TO NOISE RATIO, LF: 85dBA (A-Weighted), 80dBr (unweighted),
relative to 2.83VRMS output on LF
Click to expand...


yes, there are better... even JBL but all at higher cost. This example is entry level IMO to accurate sound source for near field monitor use. But there are many other brands andd models. Some excellent ones from Germany, too.

Would be good for some DIY'ers to start replacing their speakers with ones designed to be accurate....


-RM
 
Last edited:
#2,840
Lot of stuff in there, see below. You saying JBL does that much for 2-channels?
 

Attachments

  • 2.jpg
    2.jpg
    976.3 KB · Views: 223
Status
Not open for further replies.
Top Bottom