absolutely wrong.tomahauk said:
the 2sa1943/c5200 is only 150W and has a terrible SOAR (1.6A@60Vce) compared to the 230W MJL4281/4302 (3A@60Vce).
The MJL can just about cope (but I don't recommend it) with 150W into 8ohms from +-55Vdc supply rails.
The 2sa1943 has absolutely no hope of being reliable into the same load at that power and voltage.
As for substituting TIPs, well stand back and switch on from a safe distance.
blunt said:
If the amplifier will stand close or together with the rest of the gear, then you can put it in there. I do not know the Leach amp, so I cannot (yet) tell how to implement it. You will probably also need something to choose your source; cd-player, tele, radio . . . ?
Look at this site for dealers in DK:
http://www.miscel.dk/ElectronicShops.html
Other suggestions:
www.oxboll.dk/hga/catalog/index.php?cPath=53
www.audiokit.it/ITAENG/Cabinet/HI-FI2000/HI-FI2000.htm
www.hammondmfg.com/scpgMET.htm
www.atiresearch-anodized.com/products.html
www.machmat.com/sales/chassis.htm
www.hifi2000.it/default.asp
www.rt-audio.nl/ (look under 'behuizing')
www.hexateq-av.com
www.thel-audioworld.de/bauteile/case/case.htm
Re: Re: schematics..
If I were Anders I would start getting confused by now.
Ilimzn,
The diagram given in that particular post (#20), is to me exactly the same as the one in the reference given by "teacher". I did not read that that diagram was using BDs as output transistors - I took it that diagram was the suggestion for the more powerful version.
Blunt,
Perhaps by now academic, but were you originally using BDs also as final transistors (that is, BD139/140 driven by BD139/140), or exactly which circuit was it that you wanted to upgrade.
ilimzn said:Didn't do a very good job of stealing either
If I were Anders I would start getting confused by now.
Ilimzn,
The diagram given in that particular post (#20), is to me exactly the same as the one in the reference given by "teacher". I did not read that that diagram was using BDs as output transistors - I took it that diagram was the suggestion for the more powerful version.
Blunt,
Perhaps by now academic, but were you originally using BDs also as final transistors (that is, BD139/140 driven by BD139/140), or exactly which circuit was it that you wanted to upgrade.
Andrew,
I said that I was using TIP35C/36C for output transistors in my about 90W circuit (depending on what the mains decided to be on any particular day ....)
Certainly not for 150W into 8 ohm, but I am really posting this to ask what it is that I am overlooking. Several of these amps have been working for years (it was designed in 1994) - am I in mortal danger of something? (I have earned my pension; I am looking forward to use as much of it as possible.)
Regards
I said that I was using TIP35C/36C for output transistors in my about 90W circuit (depending on what the mains decided to be on any particular day ....)
Certainly not for 150W into 8 ohm, but I am really posting this to ask what it is that I am overlooking. Several of these amps have been working for years (it was designed in 1994) - am I in mortal danger of something? (I have earned my pension; I am looking forward to use as much of it as possible.)
Regards
Johan Potgieter said:
Frankly Johan,
i read your bio some time ago, and i'm a weeny bit surprised too.
The era of BD911/912s and any TIP power Tr. ended long before the 1990s for serious audio in my swamp.
Even then, anything more than 75 watts from a single pair of TIP35/36C would have been living on the edge.
All things relative of course.
I've had a 15-watter amp with 4 of the BD139/140 on gentle impedance/phase curve 89dB/W loudspeakers every day for weeks while i was rebuilding the regular power amp.
At serious sound pressure levels even, most of the stuff i enjoy needs a bit of volume.
4 original Philips 8 watt BD139/140, not the higher powered clones, but with bulky heatsinking for such little creatures.
A single pair of TIP35C/36C on >40 Vdc rails would not last long driving a somewhat deceiving loudspeaker, imo.
Example time :
a tulip and cheese audio guy had an output stage with 12 BD911/912 per channel in his 125<->150 watt/8 power amp, untill the mid 80s when he switched to Sanken Sumo sized ones and bumped up the power level to 200W/8.
Ths is how it looks nowadays (with fancy heatsinked Isabellenhütte emitter resistors) =>
Attachments
Well, then ...... but I did not say the TIPs were the best, if you look up, simply wondering what was wrong!
That amp was designed 13 years ago, choice of components governed by availability (you guys are more fortunate, Jacco), and I still got < 0,01% harmonic distortion, only 2nd and 3rd harmonics (i.e. anything else below threshold of audibility). G.nfb was 29dB. Not boasting, just explaining why I still make them thataway. Venture into better types here (say the mentioned MJLs) and one has to import: either quantity, expensive or both. Safe output (SOAR) is limited to 80W. But I am hunting and hoping.
But thanks for the comment (and interesting discussion in general).
Johan Potgieter said:
Johan,
i gathered as much +25 years ago from plenty of S-A people i shared time and kak praat with, heard the same from a couple of them on this gathering.
As for electronic parts, it's close to paradise overhere, ek moenie klaag nie.
Without the excess luggage, i'd have preferred living with a view at the Tafelberg long time ago.
(i need the waterfront
)ps: waar ek geboore is ons praat gelyk Afrikaans.
I've asked myself a couple of times what horrible monster loudspeakers are common in Scotland.
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