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Old 3rd July 2012, 04:31 PM   #6571
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DVV your are right about the military . When I said I needed some 2SD756 gain > 400 I was told " my friend can make those" . Knowing how genuine this friend of mine is I said how come ? It will be put in the books a a military device ! I hate to think what it would have cost . I was confidently told it would at least equal the original . Not the UK tax payer , I dare not say which country . How much should I pay ? " Oh $1.61 ( a pound ) each would be fair " .
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Old 3rd July 2012, 05:09 PM   #6572
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Originally Posted by john curl View Post
The only time I designed with a 2N3055 was for a motor driver for a servo driven capstan. Worked just fine.
Dyna started with the 2N3055, but I have only used the ST120 for a motor drive, never for audio. Perhaps, I am a 'snob', but what is the point?
There have been better complementary parts since 1967, from Motorola, so I started there. Why bother, I thought at the time, I already had a pair of Dyna MK3 power amps, with a matched pair of KT88 tubes, why use anything but the most elegant parts to try to make something better than what I already have? Even that took some doing.
When it comes to local prices and availability. Perhaps both of you are right.
When I lived in London in 1976, I used Motorola output devices MJ15002,3. They were not too hard to source.
For everyone else, my comments are based on 'What do you want to do with your time?' Do you want to fix Yugos, or old Austins, because they are available locally, cheap? Or do you want to work on old Porsches, or the like, because they promise better performance, for the time and trouble that you put in, fixing them up?
Careful with the Yugo, John.

But seriously, you are right, the Yugo was a pile of junk. And, in all fairness, you have no idea what a pile of junk. The ones which went for exports had zinc plated bodywork, the local ones didn't ans started to rust from the factory, literally. The export models used a version of the bodywork which was stiffened up for FIA Group 4 saloon racing, the local ones were as soft as paper.

SY, I am NOT talking cars here, I am trying to point out that everything that look like something may in fact be way worse that it looks, because of the time honoured communist principle to have two series of whatever, one for the domestic market (usually the worst of junk), and one for exports (usuall much better than the dometic one, even if still junk overall).

But, as with everything, even the worst of the junk can be turned into a little pearl, it's just a matter of time, knowledge deployed and money sunk into it. True of cars, true of electronics.

I have pulled a few funny ones in my time. Probably my best was a German made Wega receiver ( http://wega.pytalhost.com/1975/wega-04.jpg ), which used - you guessed it! - 2N3055 in its output stages. Nevertheless, as long as you didn't aks for too much power, it made some reasonably good music. Changing 2N3055 for MJ211xx, as well as a few critical resistors from carbon film 5% to metal film 1%, did make a hell of a difference even without fiddling with the compensation which was done to suit 2N3055. It was a friend's receiver, so no money was involved, but the pleasure of improving was all that much greater. He still has it to this day, it never broke done once.

In that year, 1975, Sony acquired Wega lock, stock and barrel, and thereafter they repackaged Sony products, so that was the last of the real Wega.

Anyway, in my book, 2N3055 has its place in the Hall of Fame, but it is most definitely history I have no wish of revisiting.
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Old 3rd July 2012, 05:14 PM   #6573
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DVV . Funny thing is some fit carbon composition as they find metal films sound harsh . I must say the best resistors I ever used were metal foil . Too expensive to use generally . I am still desperately seeking a better basic resistor . I still use MRS 25 . It's OK .

Tantalum film ? I never tried them . The capacitors put me off .

BTW . " Careful with that Axe Eugene " as the song says . Many amps osculate when better transistors are fitted . Upgrading a Goodmans Module 80 , as our engineer Leon Hendrik's said " Oh the one with smoke emitting diodes ( LED ) " the original driver had to be used as nothing seemed the better replacement . The one mod that did work was replacing the driver emitter diode with a resistor . It gave identical DC points . however it sounded better ( 56R ) . We did an IM distortion test and sure enough it was better ( some many dB ) . I see people diode bias valves . Not me even it it does work . The amp sounded wonderful after it's upgrade . It was a customer who insisted . My brother did it and got 160 for his trouble . All capacitors were replaced except some ceramics . Films were used were possible and not smaller than 100 V types , many polystyrene . To be honest a Yugo of an amp . Brave customer and his bravery paid off . He liked it for how it was domestic and not intrusive . He had a Garrard 401 so was worth the effort . My old Boss though the ultimate deity drives a Land Rover and a Transit van ( ? , I'm mystified also ) , a Harley Davidson and uses a Garrard 401 .I sort of hope my old Triumph Tiger is in his collection .

Last edited by nigel pearson; 3rd July 2012 at 05:34 PM.
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Old 3rd July 2012, 05:15 PM   #6574
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Originally Posted by nigel pearson View Post
...

Amplifiers should be upgraded from the power supply first . For me that is transformer first . ... .
Hallelujah!

Brother Nigel has seen THE LIGHT!

Completely agreed.
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Old 3rd July 2012, 05:36 PM   #6575
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I am tempted to say I always was the light when power supplies . I am certainly an evangelist . I suppose like you Dvv I had to make things work and we were very poor in those days . As a proportion of our money hi fi was something we spent money on more then than now .

My local tool shop Screwfix has a HD 320 GB hard drive PVR satellited receiver and 4 way LNB and dish for $159 . In the old days it would not buy you the cheapest pick up , 7 in 1974 ( basic wage was 14 for a kid ) , My discounted Akai AA8080 was $324 of now money or about 40% the price of a BSA 650cc motorcycle new . I was 14 at the time ( 1970 ) . I went to the shop in Silverdale Road Hayes ( Comet , near EMI and where Blumlein worked , Jordan watts also ) . I went there because no one in Oxford believed I had the money . I went to the counter and it was handed to me " go over there to pay " . the assistant totally trusted me . It was to be the Armstrong 625 , I couldn't get one ( I have one now ) . That Akai was a work of art , sonically not so hot . The FM was fantastic . I can remember on the train thinking do people know I have all this money ? Also on returning will they think that I had stolen the Akai ?

Last edited by nigel pearson; 3rd July 2012 at 05:54 PM.
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Old 3rd July 2012, 06:06 PM   #6576
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Quote:
Originally Posted by nigel pearson View Post
DVV . Funny thing is some fit carbon composition as they find metal films sound harsh . I must say the best resistors I ever used were metal foil . Too expensive to use generally . I am still desperately seeking a better basic resistor . I still use MRS 25 . It's OK .

Tantalum film ? I never tried them . The capacitors put me off .

BTW . " Careful with that Axe Eugene " as the song says . Many amps osculate when better transistors are fitted . Upgrading a Goodmans Module 80 , as our engineer Leon Hendrik's said " Oh the one with smoke emitting diodes ( LED ) " the original driver had to be used as nothing seemed the better replacement . The one mod that did work was replacing the driver emitter diode with a resistor . It gave identical DC points . however it sounded better ( 56R ) . We did an IM distortion test and sure enough it was better ( some many dB ) . I see people diode bias valves . Not me even it it does work . The amp sounded wonderful after it's upgrade . It was a customer who insisted . My brother did it and got 160 for his trouble . All capacitors were replaced except some ceramics . Films were used were possible and not smaller than 100 V types , many polystyrene . To be honest a Yugo of an amp . Brave customer and his bravery paid off . He liked it for how it was domestic and not intrusive . He had a Garrard 401 so was worth the effort . My old Boss though the ultimate deity drives a Land Rover and a Transit van ( ? , I'm mystified also ) , a Harley Davidson and uses a Garrard 401 .I sort of hope my old Triumph Tiger is in his collection .
What's "better"?

But I know what you mean. And I am hardly surprised. I see people modding their amps, taking out 100 or 130 W devices and inserting 200W devices instead. Mostly it works, but just as often, if not more often, they say they gained on sound quality, but not on quantity. Fine, I say, have you modfied the protection circuits, to suit more powerful output devices? Hell no, I ain't messin' with that, most say.

The problem with far too many mods is that they are superficial, things have been changed, but it's mostly the placebo effect at work, unless the original was like 40 years old and you stick in some yesterday's transistors, but then you risk a bit too, the original couldn't hit 1 MHz, and the new one does like 60 MHz.

Mostly, I agree with your summary, it's the power supplies which should be modded first, as that's where you maximize your gain, your bang per buck/pound/euro. A better quality transformer, preferably with more VA, with better rectifiers and better and bigger caps will defintely make each and every amp sound better, the question is only by how much.

Sometimes, yopu do get surprises, no matter what your experience is. My greatst ever suprise was when I refreshed my old HK 6550 integrated amp, put in new capacitors all around, but stuck to the original large 15,000 uF caps by some Korean manufacturer, purchased as spaere parts from HK. It worked, of course, the amp was purchased in 1993, after all, but it was hardly stunning. Then I did what I had been wanting to do for a long time, I swapped its no name volume pot with an Alps Blue, and then it took me by surprise.

If anyone asked me whther changing one pot could make much difference, I'd say it should make some difference, but no stunner. Well, I was wrong, it CAN be a stunner. I still find it hard to believe how much better it sounds now, from a solid but unexciting it had gone up in one step, to solid and exciting, since it gained sound stage depth and height I never knew it could do. I should have done that a long time ago.
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Old 3rd July 2012, 06:09 PM   #6577
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Quote:
Originally Posted by dvv View Post
Hallelujah!

Brother Nigel has seen THE LIGHT!

Completely agreed.
Nah. Amplifiers have to be upgraded from set of criteria of optimization. Then you can see what in it can be changed in order to meet the requirements. Build what you want in imagination, and compare with what you have. The remainder is what you need.
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Old 3rd July 2012, 06:15 PM   #6578
dvv is online now dvv  Serbia
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BTW, Nige, I was never poor, it's just that I had no sources to buy from.

In 1970, you say the basic wage was 17 pounds; that year, one trimester in my school in Somerset cost 950 pounds, or 56 times that, and that's just basic costs, pocket money, clothing money and travelling money was extra. That is hardly poor. (For the Americans here, in those days 950 pounds was around $2,300, about the price of a reasonable new car in those days).

Whether that money was squandered or not is not for me to judge.

Today, I have quite a number of vintage items basically sitting in my cupboards simply because I cannot listen to all of it at once. That also is hardly poor. And I sure am happy.

The truth is that I have always had more than most in Europe, about as much as US family well off fared in those days - not rich, but well taken care of.
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Old 3rd July 2012, 06:18 PM   #6579
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Originally Posted by Wavebourn View Post
Nah. Amplifiers have to be upgraded from set of criteria of optimization. Then you can see what in it can be changed in order to meet the requirements. Build what you want in imagination, and compare with what you have. The remainder is what you need.
Well, for PSUs that's easy - there is no such things as too much quality and good quantity.

Put in the biggest tranfrmer you can given the space, and make it as good as you can afford and/or care about the device being upgraded. Ditto for capacitors.

Wave, you simply cannot fail with that simple formula. THEN, after you have actually heard the improvements, decide whether you want to go on or not.
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Old 3rd July 2012, 06:28 PM   #6580
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Originally Posted by dvv View Post
Well, for PSUs that's easy - there is no such things as too much quality and good quantity.

Put in the biggest tranfrmer you can given the space, and make it as good as you can afford and/or care about the device being upgraded. Ditto for capacitors.

Wave, you simply cannot fail with that simple formula. THEN, after you have actually heard the improvements, decide whether you want to go on or not.
Put marble feet and wooden knobs. " THEN, after you have actually heard the improvements, decide whether you want to go on or not."
I like your hypnotic formula. It is classical, contains nice presupposition about "after you have actually heard the improvements".
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