After half year of hard work, planning, developing and building part by part I finally finished my MC275 copy. It is fully symmetric MKIV version including fully symmetric negative feedback. All tubes are Tung-sol, power ones are KT120s and signal tubes are balanced selected pieces. Output transformers are of my own design, amp is great in every aspect and I am very happy with the result 
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No way, you can'take fool me. That there is a McIntosh amp.
I mean, just look at it.. . it has a better finish than a McIntosh, the undersides is absolutely something you would expect from a professional amplifier build, the lettering and layout, there is nothing out of alignment, the tubes are perfectly spaced and placed, and those transformers.
No way is this stunning and breath taking build home brewed.
But, just to make sure, better send the amplifier to me so I can take a closer look at it and test it thoroughly for a long time.
That is one beautiful builld. Do you have any build pictures for inspiration?
I mean, just look at it.. . it has a better finish than a McIntosh, the undersides is absolutely something you would expect from a professional amplifier build, the lettering and layout, there is nothing out of alignment, the tubes are perfectly spaced and placed, and those transformers.
No way is this stunning and breath taking build home brewed.
But, just to make sure, better send the amplifier to me so I can take a closer look at it and test it thoroughly for a long time.
That is one beautiful builld. Do you have any build pictures for inspiration?
Thanks I built many tube amplifiers in past, so gathered a lot of experiences and I took this one seriously in every detail! I built also one version of MC275 a few years ago it is also here in build thread under #6347, but this is my "second" version, it has much better transformers in every way and has a lot better parameters and also looks much better, same as original.
I also did video with High frequency, Low frequency and max power measurements:
https://www.youtube.com/watch?v=ZwrD_4be-oE
it should be capable doing 100kHz -4dB and 200kHz -12dB, but not sure about precision of my old equipment so I need to manage some better measurements in future
I built many tube amplifiers in past, so gathered a lot of experiences and I took this one seriously in every detail! I built also one version of MC275 a few years ago it is also here in build thread under #6347, but this is my "second" version, it has much better transformers in every way and has a lot better parameters and also looks much better, same as original.I also did video with High frequency, Low frequency and max power measurements:
https://www.youtube.com/watch?v=ZwrD_4be-oE
it should be capable doing 100kHz -4dB and 200kHz -12dB, but not sure about precision of my old equipment so I need to manage some better measurements in future
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Although it is a beautiful creation, something I could never build the likes of.I love the silkscreen.Awesome!
Some future owner is going to be upset that he received an amp that will be advertised as a Mac, that isn't. Is there anyplace on the amp that states "copy"? Does it follow the original schematic? Do you have a picture of the 10K square waves?
Some future owner is going to be upset that he received an amp that will be advertised as a Mac, that isn't. Is there anyplace on the amp that states "copy"? Does it follow the original schematic? Do you have a picture of the 10K square waves?
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thanks for feedback regarding PCB I took a look at some pictures of real mac from internet pictures and tried to understand the style of traces over the PCB, rest that was not clear to me which is like 80% of traces is developed by me and my friend and make from scratch.
2scottpetersen: No way I am going to sell it to someone, not because of money but because of sentimental value for me how hard it was and how much time it took me to build it into state as it is. It is just for my own use, else I would never place someones company logo without permission. I am not that kind of person thats going to trick someone. Btw the letterings are not silkscreen, it is waterslide decal, from distance it looks great but when you look closer you can clearly see it is not silkscreen Chassis is also draw by me in CAD program and I let it laser-cut on CNC machine from polished stainless steel, bend etc. I am not sure if it fits original dimensions completely everywhere because I have never seen original real-life, but I hope it is very close.
And yes on amplifier is stated Handcrafted by "my name" not mcintoshlabs. It follows original schematic and contains all features and dislikes. (I made this fault in my first version that I personalised it for my needs and I did not like it). This "mac" is fully symmetric version of MK4 that includes fully symmetrical global negative feedback. (I think the newest MK5-6 does not have this and is smth like MK1, but dont know for sure).
Yes I have used square wave for tuning purposes to tune global feedback to no oscillations or ringing. 1k and 10k square looks really nice and quite sharp for tube amp, but I don't have any high quality DDS generator (need to buy some) I used only some shitty cmos chip generator and 10k square wave generated wasn't as straight as I would like to and thus couldn't be used for measuring slew rate f.e. But for your question yes 10k square looks nice into resistor load, into complex load with condenser paralleled (depending on how big value I use) it is a bit ringing on the edge which is anyway incredible for tube amp
regarding PCB I took a look at some pictures of real mac from internet pictures and tried to understand the style of traces over the PCB, rest that was not clear to me which is like 80% of traces is developed by me and my friend and make from scratch.2scottpetersen: No way I am going to sell it to someone, not because of money but because of sentimental value for me how hard it was and how much time it took me to build it into state as it is. It is just for my own use, else I would never place someones company logo without permission. I am not that kind of person thats going to trick someone. Btw the letterings are not silkscreen, it is waterslide decal, from distance it looks great but when you look closer you can clearly see it is not silkscreen
Chassis is also draw by me in CAD program and I let it laser-cut on CNC machine from polished stainless steel, bend etc. I am not sure if it fits original dimensions completely everywhere because I have never seen original real-life, but I hope it is very close.And yes on amplifier is stated Handcrafted by "my name" not mcintoshlabs. It follows original schematic and contains all features and dislikes. (I made this fault in my first version that I personalised it for my needs and I did not like it). This "mac" is fully symmetric version of MK4 that includes fully symmetrical global negative feedback. (I think the newest MK5-6 does not have this and is smth like MK1, but dont know for sure).
Yes I have used square wave for tuning purposes to tune global feedback to no oscillations or ringing. 1k and 10k square looks really nice and quite sharp for tube amp, but I don't have any high quality DDS generator (need to buy some) I used only some shitty cmos chip generator and 10k square wave generated wasn't as straight as I would like to and thus couldn't be used for measuring slew rate f.e. But for your question yes 10k square looks nice into resistor load, into complex load with condenser paralleled (depending on how big value I use) it is a bit ringing on the edge which is anyway incredible for tube amp
After half year of hard work, planning, developing and building part by part I finally finished my MC275 copy. It is fully symmetric MKIV version including fully symmetric negative feedback. All tubes are Tung-sol, power ones are KT120s and signal tubes are balanced selected pieces. Output transformers are of my own design, amp is great in every aspect and I am very happy with the result
Amazing
Hi all;
I'm relatively new around here, but I'm sure a few of you know me. I'm really impressed by some of the magnificent builds posted here, makes my big head feel a little smaller! So thought I share my latest, this is my fourth build, a single ended KT77, even named it. New issue Gold Lion KT77's, Jan 6Sl7's and a TAD (Shuguang) 5AR4, Transcendar output transformers. Though I did change the coupling caps to Audiocap Theta's from the original Mallory 150P's. It sounds better than my expectations. I find myself listening in triode mode most of the time.
I'm relatively new around here, but I'm sure a few of you know me. I'm really impressed by some of the magnificent builds posted here, makes my big head feel a little smaller! So thought I share my latest, this is my fourth build, a single ended KT77, even named it. New issue Gold Lion KT77's, Jan 6Sl7's and a TAD (Shuguang) 5AR4, Transcendar output transformers. Though I did change the coupling caps to Audiocap Theta's from the original Mallory 150P's. It sounds better than my expectations. I find myself listening in triode mode most of the time.
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It is a power connector made by Neutrik rated at 20A 250V. The cord end plugs in and twists and locks. They have a small spring loaded button on them to release. Here is what the other end look like. NAC3FCA Neutrik | Mouser
Here's my latest creation. A simple single ended -affair with ECC81 in the input stage and a pair of EL84's as outputs, connected in triode mode. 2W in to 8 ohms, around 2,7W before clipping.
Doesn't sound half bad to be honest. Of course, a pair of high efficiency loudspeakers are a necessity with this fleapower thing. That's why my desktop loudspeakers are made with a pair of 18Sound 8-inch coaxials. And this also easily drives my main loudspeakers with B&C 15-inch coaxes...
Oh, the name "Brachycera"... Just google it...
Doesn't sound half bad to be honest. Of course, a pair of high efficiency loudspeakers are a necessity with this fleapower thing. That's why my desktop loudspeakers are made with a pair of 18Sound 8-inch coaxials. And this also easily drives my main loudspeakers with B&C 15-inch coaxes...
Oh, the name "Brachycera"... Just google it...
