| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 270.1 | Can be good, depends on your requirements | WOTVAX::MEAKINS | Clive Meakins | Mon Apr 22 1991 13:04 | 12 |
| I built the bipolar Maplin kit which sounds reasonable, rather like a
Japanese amp with mega bass (used high quality psu capacitors). I use
it within a second system. I have spoken to someone who has built the
Maplin MOSFET amp, I was told that it is squeaky clean sounding. I
wasn't conviced the builder was 100% happy with the sound as it was
rather clinical. Maybe better with records than CD?
I've been told the SAGE amps can go unstable into any loads that are
other than easy, that may not be a problem for you though.
I've recently built a Hart kit, much more complex and expensive, but
really good - a different class.
|
| 270.2 | I have the MAPLIN 150W MOSFETS | 45235::KORMAN | tgif!! | Thu Apr 25 1991 12:22 | 16 |
|
I have been using a pair of these for a few years now. They ceratinly sound
very clean - but I would really like to compare them against something like
the Musical Fidelity or others - MAPLIN say that it's not a strictly Hi-Fi
design - it was originally designed as a bomb proof guitar amp with a valve
like sound.
Anyone like to suggest some power amps to listen to - need to be 100Wpc plus
cos I like to listen to classical music a concert hall levels! (yes, I'd
love a KSA150 - but that really is a bit expensive)
PS the MAPLINS are powered from a 500W Torroidal tranformer with 20000uF of
ELNA Audio Grade caps on each rail, all wired with very short runs of 60A
single core cooker cable, with star earthing. I have massive heat sinks on
the back of the amp, and they are certainly needed! The unit needs about � hour
to warm up before it sounds decent.
|
| 270.3 | | HAMPS::IVES_J | I've got a bad feeling, Mr Tracey! | Thu Apr 25 1991 14:03 | 5 |
| Interesting. Did you build the kits as stated, or did you make any mods
of your own ? For example I guess the kit components could be replaced
with higher quality (i.e holco resistors). Is there any protection
elements to the design ? If so could these be removed. Sounds like you
are using different power suppply and heatsinks anyway.
|
| 270.4 | designs as published. | 45235::KORMAN | tgif!! | Mon Apr 29 1991 09:57 | 23 |
|
The amps themselves were built as published - I have no doubt that different
caps etc in the signal path sound different, and that cables can be directional
etc, and to some people thses differences may sound "Better" or "Worse", but
the question is, which is more accurate? - I am into sound REproduction, not
euphony! (let's not get into a rathole here; if it works for you that's OK by
me!).
A certain degree of protection in inherent in the MOSFETs themselves - when
they get hot, the current flow decreases, so they can't go into thermal runaway
I have added DC offset protection and switch on delay using a circuit based on
a TEAC deasign that monitors the DC level at the outputs and disconnects the
speakers if it exeeds a certain level - gold plated relay is used. This has
proved useful more that once, since I use the amps for stage sound and PA work
too, and sometimes things go wrong!
I am also going to add balanced line inputs in the near future so that I can
put the amp about 100 ft or more from the mixer - I have another PA using the
MAPLIN 50W Hi-Fi modules - which also sound pretty good, by the way - that I
have already done this with and it works very well (not a hum or a buzz in
sight).
Dave
|
| 270.5 | What are audio quality components? | COMICS::GLEDHILL | | Tue Apr 30 1991 20:50 | 12 |
| Can anyone tell tell the best place to get these audio grade components?
What makes the resistors/capacitors audio grade. Higher tolerances, lower noise
or some other characteristic. Presumably if high tolerance is the main thing
you will only need to replace some parts of the circuit.
I to have recently got some Maplin Kits which I will be building.
Also, What about doubling up the mosfets and using smaller heat-sinks. I read
once that they run better that way?
Dave.
|
| 270.6 | RATA | HAMPS::IVES_J | I've got a bad feeling, Mr Tracey! | Wed May 01 1991 12:06 | 11 |
| I get some from Russ Andrews Turntable Accessories, kendal, umbria.
hav'nt got the address with me but its in the back of most hi-fi mags
under RATA.. A lot of it is expensive, but certainly the holco
resistors seem good. Much of his philosophy is never use electrolytic
caps, which is fine but the largest polypro cap he sells is 200
microfarads and about the size of a coke can !
I uprated my valve amp with his components and am pleased with the
result. I also used non-polarised electrolytics in other places and
have experimented with tantalum beads with quite good results.
|
| 270.7 | Beware of tantalum beads - I've had em explode in a puff of smoke!
| SED750::KORMAN | tgif!! | Thu May 02 1991 13:56 | 0 |
| 270.8 | oversea mail order? | ZPOVC::PARRYCHUA | Singapore, Life is bid-$-fine | Tue Jun 18 1991 02:46 | 5 |
| It mail order available from oversea (Singapore) of these kits ?
What is the full address of the dealer that offer oversea mail order ?
Thanks
Parry
|
| 270.9 | Tube/VFET hybrid | HAMPS::IVES_J | I've got a bad feeling, Mr Tracey! | Tue Aug 06 1991 18:35 | 10 |
| There is an interesting Amp kit described in the September , Practical
Electronics.
It's a valve/VFET hybrid design c#189.00
As with all these things they don't give much details of what it sounds
like but the design features some interesting features like the way
power supply regulation is done.
The styling will appeal to the "naked tube and cap" brigade
|