Now the Quasi is playing with the two small CRC Power Supply modules and its new 30 Volt 300 VA transformer, I have 42 VDC on both outputs because the line voltage is a little more than 240 V !
Now I am using a Velleman speaker protection https://www.velleman.eu/downloads/0/illustrated/illustrated_assembly_manual_k4700.pdf until I finished my own design, the first one was not good enough for negative DC
I made a single protection module for both channels that will be fixed on the rear panel directly with the speaker connectors and will not include DC fuses, see PCB layout
After that I will put it in a very small enclosure https://fr.aliexpress.com/store/pro...?spm=a2g0w.12010612.8148356.19.5f702f5bCEQd5V The amplifier modules and the CRC Power modules will be fixed on the two side heatsinks and the transformer on the middle of the bottom plate
Au revoir,
Marc
Now I am using a Velleman speaker protection https://www.velleman.eu/downloads/0/illustrated/illustrated_assembly_manual_k4700.pdf until I finished my own design, the first one was not good enough for negative DC
I made a single protection module for both channels that will be fixed on the rear panel directly with the speaker connectors and will not include DC fuses, see PCB layout
After that I will put it in a very small enclosure https://fr.aliexpress.com/store/pro...?spm=a2g0w.12010612.8148356.19.5f702f5bCEQd5V The amplifier modules and the CRC Power modules will be fixed on the two side heatsinks and the transformer on the middle of the bottom plate
Au revoir,
Marc
Attachments
Hi Hugh,
Thanks for your nice comments
I am very happy with the quality of the sound, this amplifier has a warm sound a little bit like a tube amplifier. It is not as dry as many semiconductors amplifiers but it is not too soft either, the sound is clear and by example on a test CD with cymbal you really feel the metallic sound of the cymbal with a lot of harmonic, it is very real On the same CD there is a drum track and you really feel the air coming from the speaker, this amplifier has a lot of reserve when you need it !
I have build the EL34 Baby Huey, see picture ( EL34 Baby Huey Amplifier ) that I like a lot because its particular feedback give a clear and solid sound without the softness some time associated with tube amplifier and I found the Quasi very similar in result for a much lower cost (mainly because it does not require expensive output transformers).
The previous semiconductor amplifier that I have build was based on Thermal Track dual output transistors and a NS LME49810 driver board from Panson Labs ( http://pansonaudio.com/initial_lme49810.htm ) but I was not very impressed for a much more complex amplifier, the sound was less involving
I am not a audiophile writer and I don't have the exact words to describe it, plus English is not my native language, therefor I cannot explain things clearly enough, but I really like the sound of the Quasi and I recommend it as a very good alternative to the many Chip Amplifier that we find on Audio forum. I was very satisfied also by one of these chip amp designed by Mauro Penesa with the LM3886 but the Quasi bring more power to the party...
Beside that, I have some commercial amplifiers, like a Jolida JD502B that I like a lot mainly because of the very good Svetlana SV6550C output tubes and an Accuphase E-305V that I was lucky to buy as a second hand for a reasonable price
Still I believe that the Quasi offer the best Price / Performance ratio that I have seen in Audio Amplifier. I will make more comments when it will be finished and installed in my living room with my JM Lab Electra 936 speakers...
Cheers,
Marc
Thanks for your nice comments
I am very happy with the quality of the sound, this amplifier has a warm sound a little bit like a tube amplifier. It is not as dry as many semiconductors amplifiers but it is not too soft either, the sound is clear and by example on a test CD with cymbal you really feel the metallic sound of the cymbal with a lot of harmonic, it is very real
On the same CD there is a drum track and you really feel the air coming from the speaker, this amplifier has a lot of reserve when you need it !I have build the EL34 Baby Huey, see picture ( EL34 Baby Huey Amplifier ) that I like a lot because its particular feedback give a clear and solid sound without the softness some time associated with tube amplifier and I found the Quasi very similar in result for a much lower cost (mainly because it does not require expensive output transformers).
The previous semiconductor amplifier that I have build was based on Thermal Track dual output transistors and a NS LME49810 driver board from Panson Labs ( http://pansonaudio.com/initial_lme49810.htm ) but I was not very impressed for a much more complex amplifier, the sound was less involving
I am not a audiophile writer and I don't have the exact words to describe it, plus English is not my native language, therefor I cannot explain things clearly enough, but I really like the sound of the Quasi and I recommend it as a very good alternative to the many Chip Amplifier that we find on Audio forum. I was very satisfied also by one of these chip amp designed by Mauro Penesa with the LM3886 but the Quasi bring more power to the party...
Beside that, I have some commercial amplifiers, like a Jolida JD502B that I like a lot mainly because of the very good Svetlana SV6550C output tubes and an Accuphase E-305V that I was lucky to buy as a second hand for a reasonable price
Still I believe that the Quasi offer the best Price / Performance ratio that I have seen in Audio Amplifier. I will make more comments when it will be finished and installed in my living room with my JM Lab Electra 936 speakers...
Cheers,
Marc
Attachments
Thank you Marc,
A very good description with the sorts of qualities I try to put into my designs. You captured it; thank you.....
I think you know my approach over the last decades; the design a solid state amplifier which has the best qualities of a tube - the muscle of SS and the grace of tubes. I must give a lot of credit to the Quasi however, from my QLD friend Ranchu (Christian), to Richard MacDonald in South Australia. Actually, I know one of the Australian designers of the Baby Huey, Ian Miller, who also has an old AKSA which he uses as a SS reference.
BTW, your English is excellent. You more than convey the feeling of the Quasi! Considering you probably speak three or maybe four languages, I think you'd be three or four levels above me. In Australia we only ever use one language, which has held us back in trade for two hundred years.
Thank you again, Marc!
Hugh
A very good description with the sorts of qualities I try to put into my designs. You captured it; thank you.....
I think you know my approach over the last decades; the design a solid state amplifier which has the best qualities of a tube - the muscle of SS and the grace of tubes. I must give a lot of credit to the Quasi however, from my QLD friend Ranchu (Christian), to Richard MacDonald in South Australia. Actually, I know one of the Australian designers of the Baby Huey, Ian Miller, who also has an old AKSA which he uses as a SS reference.
BTW, your English is excellent. You more than convey the feeling of the Quasi! Considering you probably speak three or maybe four languages, I think you'd be three or four levels above me. In Australia we only ever use one language, which has held us back in trade for two hundred years.
Thank you again, Marc!
Hugh
Hi Hugh,
I am pleased that you like my comments about the sound of the Quasi
I am now working on a speaker protection board before to put everything in the enclosure, but for the time being I am not satisfied with the first version I have built because it is not working correctly on minus DC over voltage
Yes, Ian Miller ( and a French guy : Yves Monmagnon http://www.dissident-audio.com/PP_ECL86/Page.html ) designed the Baby Huey and Ian helped me to make the EL34 version which have been quite successful on this forum (370 PCB sold ! https://www.diyaudio.com/forums/group-buys/312869-gb-baby-huey-pcb-62.html#post5602117 ). He also gave me some recommendation for my next project : a Quad KT120 with automatic bias and CFB based on features of the TENA amplifier from Norman Koren ( http://www.normankoren.com/Audio/TENA.html ) and the Baby Huey.
I was very interested by the optimization of the Baby Huey vacuum tube with the help of semiconductors and I think that we can build today much better tube amplifiers than in the "Golden Age" of the sixties by taking advantage of the best of both world, tubes and transistors
Beside that I only speak French and English, I was living in Geneva Switzerland for more than 40 years and I have learned German at school but I forget most of it !
Au revoir,
Marc
I am pleased that you like my comments about the sound of the Quasi
I am now working on a speaker protection board before to put everything in the enclosure, but for the time being I am not satisfied with the first version I have built because it is not working correctly on minus DC over voltage
Yes, Ian Miller ( and a French guy : Yves Monmagnon http://www.dissident-audio.com/PP_ECL86/Page.html ) designed the Baby Huey and Ian helped me to make the EL34 version which have been quite successful on this forum (370 PCB sold ! https://www.diyaudio.com/forums/group-buys/312869-gb-baby-huey-pcb-62.html#post5602117 ). He also gave me some recommendation for my next project : a Quad KT120 with automatic bias and CFB based on features of the TENA amplifier from Norman Koren ( http://www.normankoren.com/Audio/TENA.html ) and the Baby Huey.
I was very interested by the optimization of the Baby Huey vacuum tube with the help of semiconductors and I think that we can build today much better tube amplifiers than in the "Golden Age" of the sixties by taking advantage of the best of both world, tubes and transistors
Beside that I only speak French and English, I was living in Geneva Switzerland for more than 40 years and I have learned German at school but I forget most of it !
Au revoir,
Marc
Hi manniraj,
Thanks for your kind word, I have made this PCB exactly, as you said, to install it on the side heatsink, that is why I keep the height of only 60 mm like the amplifier module
I an currently designing a DC protection module for the speakers since I was not satisfied with the first one described on post 2300 I have made a first improvement on post 2325 to have a better protection on the negative side by adding a PNP transistor based on the suggestion of Jac ( lehmanhill ) here : My_Ref Fremen Edition - Build thread and tutorial
But after some tests on my first modified module, I was still not fully satisfied
and I decided to test an other design based on Elliott Sound Product Project 33 : Loudspeaker Protection and Muting It is still a work in progress but I show it here to have your possible suggestions or recommendation while I will finish it...
Cheers,
Thanks for your kind word, I have made this PCB exactly, as you said, to install it on the side heatsink, that is why I keep the height of only 60 mm like the amplifier module
I an currently designing a DC protection module for the speakers since I was not satisfied with the first one described on post 2300
I have made a first improvement on post 2325 to have a better protection on the negative side by adding a PNP transistor based on the suggestion of Jac ( lehmanhill ) here : My_Ref Fremen Edition - Build thread and tutorial But after some tests on my first modified module, I was still not fully satisfied
and I decided to test an other design based on Elliott Sound Product Project 33 : Loudspeaker Protection and Muting It is still a work in progress but I show it here to have your possible suggestions or recommendation while I will finish it...Cheers,
Attachments
Hi manniraj,
i have seen that i posted the Gerber file of the Quasi and not the CRC power supply
Here is the good one...
Rgds,
Marc
Thank you Marc
OK, this is the third version of a possible Speaker DC protection
It is based on Douglas Self book (5th ed page 465) and also used in the 21st Century protection board DC detection stage ( How to build a 21st century protection board )...
Now I have to decide which one will give best result to protect my speaker ?
I would like to know what others builders are using since there is not a lot of discussion about this subject ?
Rgds,
Marc
It is based on Douglas Self book (5th ed page 465) and also used in the 21st Century protection board DC detection stage ( How to build a 21st century protection board )...
Now I have to decide which one will give best result to protect my speaker ?
I would like to know what others builders are using since there is not a lot of discussion about this subject ?
Rgds,
Marc
Attachments
Hello Marc,
You could have a look at UPC1237 chip also, now C1237HA.
It can have over current protection and quick shut off, apart from initial start delay and dc protect.
As a last resort, to protect expensive speakers, you can take a look at crow bar protect circuit.
Apex has one such design.
Studio Reference Amplifier
regards
Prasi
You could have a look at UPC1237 chip also, now C1237HA.
It can have over current protection and quick shut off, apart from initial start delay and dc protect.
As a last resort, to protect expensive speakers, you can take a look at crow bar protect circuit.
Apex has one such design.
Studio Reference Amplifier
regards
Prasi
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Hi Prasi,
I started a schema with the UPC1237, but the test I have done on a Chinese module ( Dual channel UPC1237 Speaker Protection Board Kit Boot Delay DC Protection DIY | eBay ) were not so good
Best regards,
Marc
I started a schema with the UPC1237, but the test I have done on a Chinese module ( Dual channel UPC1237 Speaker Protection Board Kit Boot Delay DC Protection DIY | eBay ) were not so good
Best regards,
Marc
