Dx Blame MKIII-Hx - Builder's thread

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BMW850

BMW850

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Joined 2004
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Thanks Junie,

Is there someone who has already tried without the 1uF cap ?
If you're a preamplifier used with this 1uF cap is the emotion of the sound completely gone.

Therefore, said Carlos first try without preamp and and use an passive volume control, he was quite right.

My passive volume control (41-step series attenuator from Acoustic Dimension) sounds better than my active Fettle preamp, with the 1uF cap. (
Can you still follow?)

BUT only without this 1uF cap my active Fettle preamp sounds better with the 41-step series attenuator from Acoustic Dimension.

Today I also listened music with an passive Inductive Volume Control from TRIBUTE and these one is the best from all "in my set".

And if you you use passive volume control, you take a very good 1uF cap because this cap sits in the signal path.

Regards,
Rudy
 

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lanchile

lanchile

Member
Joined 2008
BMW850 said:
Thanks Junie,

Is there someone who has already tried without the 1uF cap ?
If you're a preamplifier used with this 1uF cap is the emotion of the sound completely gone.

Therefore, said Carlos first try without preamp and and use an passive volume control, he was quite right.

My passive volume control (41-step series attenuator from Acoustic Dimension) sounds better than my active Fettle preamp, with the 1uF cap. (
Can you still follow?)

BUT only without this 1uF cap my active Fettle preamp sounds better with the 41-step series attenuator from Acoustic Dimension.

Today I also listened music with an passive Inductive Volume Control from TRIBUTE and these one is the best from all "in my set".

And if you you use passive volume control, you take a very good 1uF cap because this cap sits in the signal path.

Regards,
Rudy
Click to expand...

it is a good thing to use input caps just in case of a gear connected to the inputs carries some dc...try to use a better quality cap. I use a passive volume too and I have Sonicap 4.7uf that are doing a wonderful job.;) There are better and more expensive caps ,but that does not mean they will sound better.different caps...different sound. Good luck with your hunting!
 
C

currentflow

Member
Joined 2008
space2000 said:
Hi,

Today i had changed all transistors with new including power transistors.
it still producing weak and distorted sound. high freq distorted too.

is this crossover distortion?

Regards
Michael
Click to expand...
Hi,

It's now likely that you have a board problem in the form of open or shorted tracks or an incorrect component fitted somewhere. Are you able to post a detailed picture of your board and its power wiring & grounding?

Is the lower end of R5 properly connected to ground?

Regards,
currentflow
 
A

AndrewT

R.I.P.
Joined 2004
harmonicconverger said:
i have 29-0-29 volts transformer. i'm from philippines. our voltage from outlet is 220v, but i have this large transformer with 100v labeled in the primary. can i use 110 to 220v converter?
Click to expand...
you cannot easily convert a 100Vac transformer to run from 220Vac mains supply.

You can buy a 220Vac to 100Vac transformer that will feed the correct voltage to the 100Vac transformer.
Buy the correct transformer for your 220Vac mains supply.
 
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crispycircuit

Member
Joined 2007
Pics look great! Thx !!!

Thanks for taking the time to take the pics and share them. I'm always curious to see how everyone goes about building. They look great. .... I've never seen heatsinks like that. I would guess heat won't be a problem.... This is a popular project that got raved reviews... You must be very happy!
 
J

Junie

Member
Joined 2010
lanchile said:
it is a good thing to use input caps just in case of a gear connected to the inputs carries some dc...try to use a better quality cap. I use a passive volume too and I have Sonicap 4.7uf that are doing a wonderful job.;) There are better and more expensive caps ,but that does not mean they will sound better.different caps...different sound. Good luck with your hunting!
Click to expand...

or use a Higher value maybe, 10uF is not bad or higher.
 
BMW850

BMW850

Member
Joined 2004
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Take a look in my preamp, you see 10uF Sprague Vitamin Q Paper in Oil Capacitors in the output.

Little more info from Machmat website:
Machmat FETTLE Pre amplifier

The MachMat FETTLE pre amplifier is a class A single ended pre amplifier designed around a JFET transistor.
Because of the simplicity (only a few parts in the signal), battery power supply, zero feedback and the special selected parts used, it will beat most tube based pre amplifiers in sound and specs.
This amp has very great detail, very good placement and very smooth, easy and precise sound.
A very nice amp for purists.
And cheap! Because of its simple and small design it can easily be used in 6 channel design or modifications.

Regards,
Rudy
 

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BMW850

BMW850

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Joined 2004
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Note: without the 10uF and with preamplifier

Turn on first preamplifier then the power amplifier.
First turn off the power amplifier then deflate elco's, after that preamplifier off.
And if you used a loudspeaker protection, first turn off the power amplifier ;)

so be aware of that when you use a different preamp
Click to expand...
I will certainly do, If I change to passive volume control.

Regards,
Rudy
 
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