No - feedback amplifier

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#64
Smiley 09 said:
@ The golden mean

It looks that Your amplifier is ''Green'' oriented in ''reduce mode'' very nice feature indeed,
I'm curious about the lowest ohmic ability of the amps You mention ? can the Patriot continuously drive 0,5 - 1 Ohm constant load ?

Nicest regard,

Andreas
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Here´s some pictures of the LC Audio Patriot NFB amp. Every two years i take the lid off and remove dust with compressed air and a vacum cleaner.
I don´t think it that suitable for low impedances as the output relies on four pairs of output devices (appearantly each cannel are two amps in bridge mode). The other output devices are set tio kick in in case of demand for an extra current pulse.
 

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#67
I think this Dynamic Precision A 1 amp is more apt to drive low impedances. It has 16 bipolar output transistor per channel and is capable of output 60 Ampere (120 Ampere peak) . Better in the bass department but I prefer the Patriot for the treble. But the A1 is not a no-feedback amp. It uses local feedback and an error correction along with some patented stuff.
 

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#68
Slightly OT. These two amps have some features in common, they are fast; slew rate for the AI is more than 250 V/us and think the Patriot doubles this. The A 1 has an input filter though and for one period of time there was a problem with the Patriot picking up some HF signal and one channel muted because of the protection curcuit, but this is now a solved issue.

Both amps are DC-coupled but only the Patriot has a DC servo. The A 1 has another form of protection.

The A 1 is a low distortion amp the figures are in a way "impressive" but the Patriot amp can be set in eighter single ended or symmetric operational mode, this effects the distribution of second and third etc distortion. According to the constructor Lars Clausen the one or another mode suits different types of music, I don´t care though.

In summery: these amps have different approaches and each has its strenghts. Usually people uses the same kind of amps when bi- or tri-amping but I don´t think this is mandatory. I even drive my subwoofers left and right channel with different amps an the result is amazing!
 

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#69
The golden mean said:
I think this Dynamic Precision A 1 amp is more apt to drive low impedances. It has 16 bipolar output transistor per channel and is capable of output 60 Ampere (120 Ampere peak) . Better in the bass department but I prefer the Patriot for the treble. But the A1 is not a no-feedback amp. It uses local feedback and an error correction along with some patented stuff.
Click to expand...

It looks like a fantastic amplifier... the Dynamic Precision A 1. I think this amp must have been developed later than the XP. I lost contact with LC's work after the millennium.
May I have your opinion with the sonic sound of this amp against the low-power XP or even the mk.3.1?
Rgds
 
#70
Leakstereo20 said:
"The Millennium XP" DC amplifier.

Find the link for Millennium XP on my amateur site: TUBEAMP

Secondly I have oploaded the 1995 Danish layout for "The End mk.3.1". The link for the mk.3.1 version at my site above.

Finally the question:

I asked the owner of L.C.Audio whether he would consider to produce the PCB and component kit for the 3.1 and the Millennium once again. The owner said that the minimum order for him was 100 pcs. of the PCB either for the 3.1 or the Millennium.

I have a responce gmail which is: kim.jul.hansen2012@gmail.com
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Is there DIY people from outside Europe with interest that you once again could have the opportunity to buy a "The End mk. 3.1" or Millennium kit?

Amplifier kit will consist only of PCB's, components and assembly instructions. Cabinet choice is on your own.

LCAudio can order 100 PCB's and components for either 3.1 or XP as minimum.....

There is now a need to make comments and wishes.

Is there interest? .... if any use. kim.jul.hansen2012@gmail.com
with your name and address.

I am perhaps too late out because the number of DIY electronic girls and boys has plummeted during the last two decades.
 
#74
Replacement transistors

Anyone who knows replacement transistors for the discontinued Sanken 2SC2922 and 2SA1216?

2SC3722K smd seems to have data like 2SC2240 exept for the noise.
0,2dB/100uA for 2SC1455 and 0,5dB/100uA for 2SC2240
2SA1455 smd with data as 2SA970 ...exept for the noise.

2SA970/2SC2240 could be used as input pair in The End mk.3.1??

The End mk.3 PCB:

https://picasaweb.google.com/vbkolsen/TheEndMk311995DanishManualAndSchematic#5841881461722260994

The End mk.3 schematic:

https://picasaweb.google.com/vbkolsen/TheEndMk311995DanishManualAndSchematic#5840325839818957314
 
#75
Gudmund said:
Anyone who knows replacement transistors for the discontinued Sanken 2SC2922 and 2SA1216?

2SC3722K smd seems to have data like 2SC2240 exept for the noise.
0,2dB/100uA for 2SC1455 and 0,5dB/100uA for 2SC2240
2SA1455 smd with data as 2SA970 ...exept for the noise.

2SA970/2SC2240 could be used as input pair in The End mk.3.1??

https://picasaweb.google.com/vbkolsen/TheEndMk311995DanishManualAndSchematic#5840325839818957314
Click to expand...

Not sure that Sanken 2SC2922 and 2SA1216 are discontinued.

Not sure whether "2SA970/2SC2240 could be used as input pair in The End mk.3.1??" ....either?
 
#77
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