Doxa 70 SE Amplifier

ManUtd · 22nd March 2005, 02:59 PM

Hi All!

I am about to change a defective transistor inside this amlifier.
One channel has 6pcs BD246C and 6pcs BD245C.
Those six are coupled in paralell.

I need to replace one piece of BD245C.

I have at hand TIP35C,BD249C and some 2sc**** 2SD****

Can they be used as replacement in this case?

Thanks for Your comments.,
ManUtd.

PMik · 22nd March 2005, 06:11 PM

you need to use pairs of TIP35C/TIP36C ....if you mount just one single TIP35C, the outcome will be unsure.

ManUtd · 22nd March 2005, 08:00 PM

Pairs?

There is six of each(BD246C and BD245C) in paralell.
But could i use eg. 6* BD246C and 6*TIP35C ?

Quote:

Originally posted by PMik
you need to use pairs of TIP35C/TIP36C ....if you mount just one single TIP35C, the outcome will be unsure.

PMik · 22nd March 2005, 08:53 PM

Exactly...they are the nearest replacement for the BD245/BD246

The TIP's have better specs compared with the BD's ...it will be an upgrade

ManUtd · 22nd March 2005, 09:16 PM

Thanks,
Already ordered 6 pcs TIP33C.
I think this is correct replacement for BD245C.
And i leave BD246C as it is,no change.

Quote:

Originally posted by PMik
Exactly...they are the nearest replacement for the BD245/BD246

The TIP's have better specs compared with the BD's ...it will be an upgrade

PMik · 22nd March 2005, 09:53 PM

Im sry to say, but i think its a really sad event

when you spoile

a really nice amplifire, by saving very! few bucks

ManUtd · 22nd March 2005, 10:45 PM

What do You mean?
TIP33C is a direct replacement for BD245C.
This amp was Originally built for BD245C and BD246C and it sounds well
with those transistors as well.
Why is will it sound better with TIP35C,TIP36C ???
Please advice why.

Regards,
ManUtd.

Quote:

Originally posted by PMik
Im sry to say, but i think its a really sad event
when you spoile
a really nice amplifire, by saving very! few bucks

PMik · 23rd March 2005, 05:45 AM

What i mean is to use two different Types, brands of semiconductors, will for sure raise the THD

I have heard the amp you got....its one of the better ones, and afir ....its uses low global feed-back .....you have to make it as symetrical as possible to keep or better improve specs, this is crucial point.

Other types of power-transistors besides the TIP/BD's could be used ....But the TIP's are the cheapest of them all

ManUtd · 23rd March 2005, 07:45 AM

Thanks Pmik,

I think i understand.
If i change to TIP33C instead of BD245C i should also change BD246C to TIP34C in the same time?
Then there is a matching pair again?

Reg,
ManUtd.

Quote:

Originally posted by PMik
What i mean is to use two different Types, brands of semiconductors, will for sure raise the THD

I have heard the amp you got....its one of the better ones, and afir ....its uses low global feed-back .....you have to make it as symetrical as possible to keep or better improve specs, this is crucial point.

Other types of power-transistors besides the TIP/BD's could be used ....But the TIP's are the cheapest of them all

PMik · 23rd March 2005, 05:14 PM

Yeah!

keep it "clean" by replacing parts symetrical, if you cant get a part .....you have to replace in both channals...this is not a cheap amp...it was made for wanna be/have high End gear users

Ps. Audio 60 made by the same engineer, was also a nice "bang for bucks" amplifire

22nd March 2005, 02:59 PM	#1
ManUtd diyAudio Member Join Date: Sep 2003 Location: Hof,Norway with Nice Mountains!	Doxa 70 SE Amplifier Hi All! I am about to change a defective transistor inside this amlifier. One channel has 6pcs BD246C and 6pcs BD245C. Those six are coupled in paralell. I need to replace one piece of BD245C. I have at hand TIP35C,BD249C and some 2sc** 2SD** Can they be used as replacement in this case? Thanks for Your comments., ManUtd.

22nd March 2005, 06:11 PM	#2
PMik diyAudio Member Join Date: Mar 2004 Location: Fort Lauderdale, FL	you need to use pairs of TIP35C/TIP36C ....if you mount just one single TIP35C, the outcome will be unsure. __________________ Mod is fun

22nd March 2005, 08:53 PM	#4
PMik diyAudio Member Join Date: Mar 2004 Location: Fort Lauderdale, FL	Exactly...they are the nearest replacement for the BD245/BD246 The TIP's have better specs compared with the BD's ...it will be an upgrade __________________ Mod is fun

22nd March 2005, 09:53 PM	#6
PMik diyAudio Member Join Date: Mar 2004 Location: Fort Lauderdale, FL	Im sry to say, but i think its a really sad event when you spoile a really nice amplifire, by saving very! few bucks __________________ Mod is fun

23rd March 2005, 05:45 AM	#8
PMik diyAudio Member Join Date: Mar 2004 Location: Fort Lauderdale, FL	What i mean is to use two different Types, brands of semiconductors, will for sure raise the THD I have heard the amp you got....its one of the better ones, and afir ....its uses low global feed-back .....you have to make it as symetrical as possible to keep or better improve specs, this is crucial point. Other types of power-transistors besides the TIP/BD's could be used ....But the TIP's are the cheapest of them all __________________ Mod is fun


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23rd March 2005, 05:14 PM	#10
PMik diyAudio Member Join Date: Mar 2004 Location: Fort Lauderdale, FL	Yeah! keep it "clean" by replacing parts symetrical, if you cant get a part .....you have to replace in both channals...this is not a cheap amp...it was made for wanna be/have high End gear users Ps. Audio 60 made by the same engineer, was also a nice "bang for bucks" amplifire __________________ Mod is fun

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