Mr. Pass

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
Not without some resistance in series with each diode also -
we have to avoid current hogging.

Generally when you put diodes in parallel with emitter/source
resistors, you are looking to limit the forward drop at high
currents and/or have more resistance for bias stability at lower
currents. I used something like this about 35 years ago, and
I'm aware that it also appeared in the HP "Barney Oliver" amplifier.
 

thylantyr

Member
2001-02-19 10:38 pm
Mars
Thanks for the info.

This came up on another forum as certain car audio amplifiers
from two established manufacturers use this scheme. I don't
know who else at the moment. I never saw it done before.

The two manufacturers are Soundstream and Genesis.
In 2003, I asked if you did designs for Soundstream in
the early days -> yes

but I didn't see that scheme implemented in those original
amplifiers, as I saw some gut pictures.

Further researched showed that Wade Stewart had a hand
in later Soundstream products, then later Gordon Taylor's
Genesis products had this scheme.

Another internet search shows Wade having this business.
http://www.stewartaudio.com/

I guess I wanted to also see if he uses this scheme in the pro
audio amps he makes.

This scheme is almost akin to a fingerprint because the idea
seem so esoteric. If someone were to copy a design, they'd
copy the fingerprint unbeknownst to them that it's very unique,
implying they took the idea from someone else.

The 'who copied who' question got raised. :hot:

While that isn't that important, I was more interested in know
why this scheme would be used.
 

clwong168

Member
2008-03-09 6:36 am
I am a happy owner of X600. I have few suggestions to made:

To get sound as natural as possible and extension as wide as possible, I found to do the few things will help:

1. losing the nuts on all the Transformers and hand tighten it without any force.

2. Loosing all the cable ties

3. Remove all the Plastic cable heatshrinks and replaced with vinyl electrical tape but loosely binded.

The reason to do all these : To release any undue stress on the amp.

Your commends please,

clwong168
 

clwong168

Member
2008-03-09 6:36 am
There is another cheap way to improve my x600 Amp: The Power supply cable of X600.
All Power Cables offer in the market are heavily shielded and are tightly wrapped with Heatshrink and the wires are screwed tightly. I removed all the Heatshrink, throw away all the nuts/screws of the terminal and using silver solder to weld the wires to the terminal instead. It will improve the sound quality.
 

Babowana

Formerly "jh6you". R.I.P.
2006-07-13 4:23 pm
www.aheadamp.com
clwong168 said:
I am a happy owner of X600. I have few suggestions to made:

To get sound as natural as possible and extension as wide as possible, I found to do the few things will help:

1. losing the nuts on all the Transformers and hand tighten it without any force.

2. Loosing all the cable ties

3. Remove all the Plastic cable heatshrinks and replaced with vinyl electrical tape but loosely binded.

The reason to do all these : To release any undue stress on the amp.

Your commends please,

clwong168



Reading this, I really don't know where is the border line between the seriousness and the joke . . .



:darkside:
 

clwong168

Member
2008-03-09 6:36 am
PUT JOKE ASIDE, PLEASE. I am Serious

I put forward my findings in this forum to share. I am not joking.
It cost you nothing to try it. To loosing the nut on Transformer is easiest way to try, you can revert back if you do not like the sound. (Beware not to loose too much that the nut come out of the Transform. It will be difficult to fix back the nut)

I do not post here to joke but sharing. If you do not tried before, you should not give comments. How Do you know?

The principle behind what I am doing are to release any stress in the amp in ordere to get better sound quality.
 

Babowana

Formerly "jh6you". R.I.P.
2006-07-13 4:23 pm
www.aheadamp.com
If you loosen your nut first, you might feel 100%-different sound.
If you re-tighten the nut, you might feel 90%-different sound.
If you re-loosen the nut, you might feel 80%-different sound.
If you re-tighten the nut, you might feel 70%-different sound.
If you repeat these, you would finally feel no more difference.
Then, you are now out of self-hypnosis . . .

Try . . . seriously . . .

By the way, when you tighten the nut, be careful not to destroy the mechanism . . .

Cheers,


:darkside:
 

clwong168

Member
2008-03-09 6:36 am
Unfriendly Remark

Degree of tightening nut just like adjustment. You have to do it right by using your ear to listen. However, If you do not have a ear to distinct the difference, then DIY have no meaning to you.


I come in this forum in hoping to have some constructive and friendly discussion. Unfriendly remark just destroying "DIY" spirit.


l
 

Babowana

Formerly "jh6you". R.I.P.
2006-07-13 4:23 pm
www.aheadamp.com
You are totally right. I'm not friendly to everyone.

Last 20 years, I have done similar tests as I wrote above with different capacitors, resistors, transformers, bolts and nuts, speaker cables, interconnection cables, shieled cables, twisted cables, tinned wires, silver-plated wires, voccum tubes, etc . . . to see many different effects . . . There were some differences in some area but not as much as I have expected . . .

Try as I mentioned above and come back. Otherwise, you will do destructive and tasteless contribution to this forum.


:darkside:
 

clwong168

Member
2008-03-09 6:36 am
My last posting in this Forum, Thanks Mr. Pass

It is no point to try blindly without knowing the basic requirement of sound. It just waste your time.

Sound qualities I am looking for are: Natural, Good seperation, Frequency Extension as wide as possible and high, mid and low frequencies blind together well in equilibrium.

I afraid by only change electronic parts WILL NOT ACHIEVE these goal.s It is the total setup : Like Cables, POWER and PRE AMP, Player, Speaker and Your Room as well as placement of your speakers.

The key word is "ALL PARTS IN THE SETUP MUST BE COMPETABLE WITH ONE ANOTHER". To achieve the goal, the start point is to make sure no stress in any part of your set up. This is only the starting point.

I learnt this approach from someone who have achieve the goal better than me.

I must point out once again by change electronic parts is not the best or only way to improve your sound quality.

This is my last posting in this Forum and unfirendly remarks is not appreicated.
 
Guys, lighten up.
Although I honestly can't see any benefit to loosening the screws on a power transformer, I learned long ago not to say 'never' when someone came up with something that seemed odd at first. Some of the 'impossible' things--or at least I thought they were impossible--turned out to be audible and some did not (at least not to me).
If you'll allow me to play devil's advocate for a moment:
--Somewhere down in the Dungeon is an EI power transformer that mechanically hums due to loose laminations.
--If I tighten the screws the laminations flex and buckle in the middle between the screws and the humming gets worse.
--If I loosen the screws the humming abates somewhat, though not entirely.
Thus...
--It's annoying to have noise in the background while you're trying to listen to music. If someone has no better use for their time, it might be interesting to have a count of threads here at DIY relating to humming transformers. I can recall a half-dozen or so without even trying hard.
--If you take it a level deeper, the energy that causes the laminations to vibrate represents a loss of magnetic flux that would ideally be better applied to the secondary windings. It's not a lot of energy, but it's there.
I once knew a girl whose basic world view bordered on true clinical paranoia. In any and every case where someone did or said something to her or even in her presence, she placed the worst possible interpretation on the event. In attempt to get her to be a bit less negative I asked her to contemplate the idea--not that every action has two possible interpretations, that's trite--but that there were at least three possible interpretations to every action: a positive one, a negative one, and a neutral one.
I can't say that I'm persuaded by clwong168's proposal, but it wouldn't hurt to consider one or two other possibilities besides the "he's clearly a nutcase" conclusion that some appear to have reached.

Grey