There are two types of microphone low noise cables ,75 ohms used for dynamic mics single wire and 600ohms condenser mics two wires . The impedance value doesn't matter at all.
Sounds very very good. Got that natural bloom in the sound.
Epuld be great of one can scale it to 50 watts & retain the same
SQ. Congrats
Epuld be great of one can scale it to 50 watts & retain the same
SQ. Congrats
Thanks Mr K,
I will use the 100 Ohm twisted wires with shield.
So far, it is nearly completion, waiting for PCBs etching, I think the amp will be a laughingstock for high end builders by my choice of non “audio grade” components (with an exception for the lateral mosfets), SMPS and CPU fan heatsink.
Cheers
Attachments
Hi Sumo,
Thanks for your kind words,
It can be scale up with more powerful devices such as
Device: ECF20N20 (2SK176)
Polarity:NPN
Vceo:200V
IcA:16A
Ptot:250W
Package: TO-3
Device: ECF20P20 (2SJ56)
Polarity😛NP
Vceo:200V
IcA:16A
Ptot:250W
Package: TO-3
Cheers
Hi MosFed,
Kudos to your effort really. I only can build & tweak. Lol What I think that I'm really good at is listening, meaning how an instruments sounds like in real & how to mimic this in our projects which off course is tweaking all the time & also killing many projects along the way. I really like the sound of your amp, you can hear it blooms without being congested or nasal. How does it sound when playing complex music ? Keep up the good work.
Cheers
Btw are those smps psu that I see in the pic ?
Kudos to your effort really. I only can build & tweak. Lol What I think that I'm really good at is listening, meaning how an instruments sounds like in real & how to mimic this in our projects which off course is tweaking all the time & also killing many projects along the way. I really like the sound of your amp, you can hear it blooms without being congested or nasal. How does it sound when playing complex music ? Keep up the good work.
Cheers
Btw are those smps psu that I see in the pic ?
While I am waiting for a double shielded toroid power transformer, they are the work horses, +20V/2A and -20V/2A each
Today I work on the fascia, mounted two dB meters, a question in my mind, what is for?, perhaps “noblesse oblige”.
I think that I don’t have to go too far for the pcb, my SCB (scribed circuit board) is doing fine.
Cheers
Attachments
Your gonna finish the amp that quickly & no tweaking ? Lol.
Btw those philips LH caps that your using sounds pretty good but are not that transparent. Your recommedation of scaling up for higher output, wonder how it would do with low impedance speakers.
Thks again
Btw those philips LH caps that your using sounds pretty good but are not that transparent. Your recommedation of scaling up for higher output, wonder how it would do with low impedance speakers.
Thks again
I haven’t tried the higher output bi-circleton yet, the transistors that I mentioned are double dies, assuming that it will double the amount of current, then Ohm’s law applies to Z, output impedance will be lower Under same circumstance compared to a single die.
English is my third language, so I have to keep myself out of any “sound description” essay. In the Bi-Circleton PS circuit caps are used for energy storage, not DC blocking, I use whatever i got at hand, those Philips are 30YO, they sound nice like Rémy Martin XVSOP.
Today I finish the left side, we had a long weekend here, so time was spent with family. I received this morning my copper plate, it will be the base for heatsinking. YouTube
English is my third language, so I have to keep myself out of any “sound description” essay. In the Bi-Circleton PS circuit caps are used for energy storage, not DC blocking, I use whatever i got at hand, those Philips are 30YO, they sound nice like Rémy Martin XVSOP.
Today I finish the left side, we had a long weekend here, so time was spent with family. I received this morning my copper plate, it will be the base for heatsinking. YouTube
Its sounding pretty good MossFed. I have some Buz 900 lying around but got to get the Buz 950. Guess I could use them right ? I’ve got a pair of 40-0-40 ac 300va trafo. Wonder if voltage is too high for this application. Btw English too is my third language
Thanks for your advice
Thanks for your advice
YouTube
First attempt on 2 channels, after 1/2 hour right channel became unbalanced, 200mV DC, thought that from driver stage, then found out that right SMPS is unbalanced.
The test keep going with righ channel powered by bench PSU, doesn’t sound great like the source
Music video on song Luciano Pavarotti "Caruso" on Vimeo
First attempt on 2 channels, after 1/2 hour right channel became unbalanced, 200mV DC, thought that from driver stage, then found out that right SMPS is unbalanced.
The test keep going with righ channel powered by bench PSU, doesn’t sound great like the source
Music video on song Luciano Pavarotti "Caruso" on Vimeo
My fav Pavrarotti peace from Denon label. Are you going to replace the smps ? My experience even with Hypex is not as good when compared to a properly set up linear supply.
Cheers.
Cheers.
Bi-Circleton PSU is +-22V, had purposely aiming for low cost 10mF/25V cap (Aud $0.5 ea.)
You can use +-48V to suit the transformer, B900 & 905 are within safe operating area.
May be I will use linear PSU if my SMPSs are unable to do their job, they run as master and slave to avoid interference in audio bandwidth, 2 amp limit as safety bonus for topping up 100mF caps ( I already ordered 100 x 10mF/25V capacitor)
I use whatever available at hand, the budget for this amp is very low to your surprise, mostly from my chuck shed such as recycled 19” aluminium case, meters from boat anchor equipment, SMPS from junkyard...
Most expensive part is the copper plate (Aud$60) but for 2 projects. 100 caps $50, Semiconductors $20.
That’s all and will see for next test.
Today is labour day, means cutting the plate with hacksaw, drilling and threading holes to optimise heat dissipation revealed a few weak point from yesterday test.
Cheers and nice WE
Attachments
The temporary aluminium plate was replaced with copper 10mm for maximum heat transfer to the CPU fan at a very low rpm, able to sink 150W with fan spinning at 8Vdc.
The toroidal transformer for dual 9Vac supplies also been rewound with double shields, each 9Vac lead to shield with 10k resistor beard 0.0mVac and 0.1mVac
Australia post send an email for optional delivery of the 100 x 10000uF (at work - safe drop - parcel locker....) that impressed me, very kind gestures.
Cheers
The toroidal transformer for dual 9Vac supplies also been rewound with double shields, each 9Vac lead to shield with 10k resistor beard 0.0mVac and 0.1mVac
Australia post send an email for optional delivery of the 100 x 10000uF (at work - safe drop - parcel locker....) that impressed me, very kind gestures.
Cheers
Attachments
So much for buying from China. Lol
Will plan for the next project building this amp.
Thanks for sharing your built.
Will plan for the next project building this amp.
Thanks for sharing your built.
First wheel challenge
The driver (first wheel) is very challenging to duplicate while having a very low noise output, mainly due to its floating power supply. I Will try the aikido when time permitted by injecting opposite phase for noise cancellation.
Floating Power Supplies & Inverted SRPP
https://www.tubecad.com/2015/09/19/Inverted%20SRPP%20with%20Floating%20Power%20Supply%202.png
According to the schéma provided by Mr K, filtering is done by a 2mF cap, on my build it will yield from -40 to -60dB of ripples noise (50Hz & 150Hz).
I manage to get that ripples down to a level of -80dB by using C-R-C filter.
Here is my rebuild drivers:
The driver (first wheel) is very challenging to duplicate while having a very low noise output, mainly due to its floating power supply. I Will try the aikido when time permitted by injecting opposite phase for noise cancellation.
Floating Power Supplies & Inverted SRPP
https://www.tubecad.com/2015/09/19/Inverted%20SRPP%20with%20Floating%20Power%20Supply%202.png
According to the schéma provided by Mr K, filtering is done by a 2mF cap, on my build it will yield from -40 to -60dB of ripples noise (50Hz & 150Hz).
I manage to get that ripples down to a level of -80dB by using C-R-C filter.
Here is my rebuild drivers:
Attachments
Last edited:
But once you use Akido front end sound will no longer be the same.
What about a regulated supply ?
What about a regulated supply ?
Today I have done the thermal test, fan spinning on 8V, sinking 140W from two channel to 49 deg C, very little noise.
YouTube
The CRC Filter in my first wheel, 8mF - 2R2 - 8mF, passes 0.002Vac ripple, is a band-aid solution, seems I haven’t got the right technique yet.
Aikido is a technique For neutralisation power supply noise by inserting opposite noise phase, nothing change with the first wheel topology.
Regulated supply, or much better is “cap multiplier” is degrading the elegance of the circuit.
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