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Cosmic LAB-3000 Stereomaster Amplifier Schematic

Wharfedale Speakers

Danieljohn

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Dear All !
What's soo Distinctive about BC157A 24K Glod lead Transistors?
I was told this sounds superior to BC547A . IMG-20181128-WA0012.jpg
 

reubensm

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nice to see these old silicon transistors, used loads of them, 147A/B, 148A/B/C, 149A/B/C

whether they sounded better than BC5xx series, well I could not find any difference :)

but yes, the 107, 108 and 109 were much better in my opinion
 

reubensm

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no, the BC157A and its peers were not the same as the metal body 107, 8 and 9. The 10x series were far better transistors in my opinion especially on the noise front.

The transistors that you mentioned the BC 14x and 15x series were used in general audio circuit designs, from portable radios and cassette recorders to amplifiers. I still remember these used to cost Rs.2 back in those times :)
 

deepakkadam

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I was told by a Amplifier builder that Cosmic LAB-3000 was basically a Philips 40+40 watts amplifier circuit from 1970's-80's but with 2N3055 output Transistors. If anyone happen to be having Philips Amplifier Schematic kindly let me know. I tried online but didn't found it.

Thanks in Advance !
Please try with EFY
 

rupy

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I was told by a Amplifier builder that Cosmic LAB-3000 was basically a Philips 40+40 watts amplifier circuit from 1970's-80's but with 2N3055 output Transistors. If anyone happen to be having Philips Amplifier Schematic kindly let me know. I tried online but didn't found it.

Thanks in Advance !
No.It was not the philips circuit mentioned by you.
 

Bhupinder Singh

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This is not true. Cosmic Lab 3000 was a direct coupled amplifier powered by dual rail power supply. And so was Lab 5000 & Lab 6×1000.
All the CO series were powered by single supply rail.
And were capacitor coupled to the speaker load .

Each and every Philips amplifier manufactured in India had a circuitry powered by a single rail power supply capacitor coupled to output load or speaker.

Sonodyne amplifiers were similar to the Cosmic Lab series .... powered by dual symmetrical power supply coupled directly to the speaker load.

I had repaired several Cosmic, Sonodyne and Philips amplifiers in those days which were quite popular and common among audio lovers in the late 80 - 90s.

Lab 3000 circuitry is quite similar to Sonodyne's SA5000 & SA6000 amplifiers.
@SIDEWINDER18X kindly let me know what is the per channel power output of cosmic lab 3000 amp.?
 

veekm

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This is not true. Cosmic Lab 3000 was a direct coupled amplifier powered by dual rail power supply. And so was Lab 5000 & Lab 6×1000.
All the CO series were powered by single supply rail.
And were capacitor coupled to the speaker load .

Each and every Philips amplifier manufactured in India had a circuitry powered by a single rail power supply capacitor coupled to output load or speaker.

Sonodyne amplifiers were similar to the Cosmic Lab series .... powered by dual symmetrical power supply coupled directly to the speaker load.

I had repaired several Cosmic, Sonodyne and Philips amplifiers in those days which were quite popular and common among audio lovers in the late 80 - 90s.

Lab 3000 circuitry is quite similar to Sonodyne's SA5000 & SA6000 amplifiers.
Thank you - just got my paws on a Cosmic LAB 5k MK2 with one channel AWOL (faint audio) and I was wondering about the Class and such. Would you be able to identify some of the components - I am unfamiliar with some of them.

Are you sure the Cosmic LAB5kMK2 is Direct Coupled.. it has 2x2 power transistors with each set driving one set of speakers and I have a problem with one speaker/power-transistor-channel-thingy..
 

SIDEWINDER18X

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Thank you - just got my paws on a Cosmic LAB 5k MK2 with one channel AWOL (faint audio) and I was wondering about the Class and such. Would you be able to identify some of the components - I am unfamiliar with some of them.

Are you sure the Cosmic LAB5kMK2 is Direct Coupled.. it has 2x2 power transistors with each set driving one set of speakers and I have a problem with one speaker/power-transistor-channel-thingy..
I am 100% sure. It is direct coupled.
 

veekm

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I am 100% sure. It is direct coupled.
okay so it uses a BC147A+HL100 and the power transistors (4 of them) to drive 2 spkrs (left spkr and right spkr) in 'A+B' mode.. The two power transistors are direct coupled? BC147+SL100 for voltage amp - to get the signal strength up? Any idea what the part number is.. mine is blackened.. (2N3055?)

Also, what's the purpose of the other two ports - recollect there are 4 ports so if 2 ports are being driven by the 4 power transistors.. then what drives Port 1,3?
 
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