The grounding scheme is unusual.
No star ground. A mesh ground plane that connects to all ground traces.
The high current traces, the small current traces and the ground plane are all connected.
...
No star ground. A mesh ground plane that connects to all ground traces.
The high current traces, the small current traces and the ground plane are all connected.
...
Boards have arrived for the Simpelstark amplifier. I haven't had a chance to assemble and test one yet though.
My camera is smashed. They look the same as the version Valery built but with the corrected op amp connections.
BTW, went ahead and bought the Rigol scope you suggested. Received it two days ago but have yet to fire it up. Looks like a really nice scope!
Thanks
Do
Thanks
Do
Nice! They're a great little scope for the money. More than enough functions for audio as well.
Great move!
A scope is a must-have instrument as far as you deal with sophisticated electronics.
Otherwise - "It's difficult to find a black cat in a dark room. Especially if it's not there" 😛
My Simpelstark+ V1.3
Hello All,
Here is my home build of Simpelstark.
More detailed post - in the Solid State Pics Thread.
I've got a fully dual mono configuration - separate transformers, separate PSUs, optocoupled protection.
Very happy about this build - I'm going to use it as my main amp at home for a while 🙂
Cheers,
Valery
Hello All,
Here is my home build of Simpelstark.
More detailed post - in the Solid State Pics Thread.
I've got a fully dual mono configuration - separate transformers, separate PSUs, optocoupled protection.
Very happy about this build - I'm going to use it as my main amp at home for a while 🙂
Cheers,
Valery
Attachments
My attempt to measure SNR - not as precise as I'd like to, but it gives an idea:
Simpelstark SNR measurements
Simpelstark SNR measurements
Hi Valery,
Nice measurements for a no global feedback amplifier !
What's the recommended rail voltage and transformer VA for 3-4 ohm speakers ?
Regards
Nice measurements for a no global feedback amplifier !
What's the recommended rail voltage and transformer VA for 3-4 ohm speakers ?
Regards
Hi Danny,
Simpelstark V1.3 can drive 4 ohm speakers up to 160W as is.
However, if you need less power, it will feel more comfortable running at some lower rails voltage with those low-Z loads.
What kind of power rating do you have in mind?
Cheers,
Valery
P.S. Nice speakers by the way
😀
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Hi Valery,
They're about 93db sensitive.
I once tested my speakers and with 1.5V I get 91-92dbc at listening position.
I don't need the high voltage just more current.
I've just finished with a redesign of my speakers, with the new crossover they're now a little easier load, dip is 3.2ohm (100-200Hz)
I enjoy your threads about your different amplifiers, very nice concepts.
Regards,
Danny
They're about 93db sensitive.
I once tested my speakers and with 1.5V I get 91-92dbc at listening position.
I don't need the high voltage just more current.
I've just finished with a redesign of my speakers, with the new crossover they're now a little easier load, dip is 3.2ohm (100-200Hz)
I enjoy your threads about your different amplifiers, very nice concepts.
Regards,
Danny
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Maybe this article of 2017 is interesting.
Distorsion Reduction
More Distortion-Reduction & Taming the Triadtron
Distortion Reduction
Distorsion Reduction
More Distortion-Reduction & Taming the Triadtron
Luxman L-590A
The idea is quite similar to D. Bollen's scheme: a power amplifier's output is attenuated to match the input signal and the difference between these two signals is first inverted and then mixed with the input signal fed to the power amplifier, theoretically resulting in a large reduction in distortion. Here is the actual implementation from the review.
Distortion Reduction
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Luxman L-507 uXII
After reading this thread: I went from Class D to Luxman A/AB - And most of what you think is wrong | Audiogon Discussion Forum
I searched for info about Luxman 507
L-507uXII | INTEGRATED AMPLIFIERS | PRODUCTS | LUXMAN | Seeking higher sound quality
After reading this thread: I went from Class D to Luxman A/AB - And most of what you think is wrong | Audiogon Discussion Forum
I searched for info about Luxman 507
L-507uXII | INTEGRATED AMPLIFIERS | PRODUCTS | LUXMAN | Seeking higher sound quality
ODNF* Version 4.0 innovative amplification feedback circuit
An integral part of the design of the L-507uXII is LUXMAN’s original ODNF amplification feedback circuit. This features a fast-primary slew rate and an ultra-wide bandwidth that is achieved through the feedback of distortion components only from the amplification output circuit.
The latest version of ODNF–Version 4.0–is used, resulting in a dramatic enhancement of accuracy in distortion detection, lower impedance and a higher S/N ratio due to a parallel first stage and Darlington connected second stage of the amplification circuit, as well as a 3-parallel first stage error detection circuit.
A 3-parallel push-pull structure output stage achieves complete output linearity of 110W+110W (8Ω) and 210W+210W (4Ω). This type of circuit can achieve high power ratings that are comparable to a separate amplifier and has the force to drive various speaker systems to deliver high grade sound reproduction.
*ODNF stands for "Only Distortion Negative Feedback".
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Valery, Jeff,
On the BoM for C7-C8, C14-C15, it states 100uF 100V caps. Unfortunately, the pitch is 3.5mm and themax size that will fit is 10mm diameter... Do we really need 100V?
Thanks
Do
On the BoM for C7-C8, C14-C15, it states 100uF 100V caps. Unfortunately, the pitch is 3.5mm and themax size that will fit is 10mm diameter... Do we really need 100V?
Thanks
Do
Those caps will see rail voltage so 63V should be fine there. Something like this should be good. UVY1J101MPD Nichicon | Mouser Canada