On Oct 21, 8:57*pm, Big Bad Bob BigBadBob-at-mrp3-
wrote:
On 10/21/10 02:09, Patrick Turner so witilly quipped:
On Oct 21, 3:36 am, "Edward *wrote:
Hello,
* * *I'm interested in Velleman tube amp kits. *Does anyone know if Velleman
has quality products?
Thanks,
Eddie
And I had a look at the Velleman schematics which can be found in the
online kit manuals.
snip
I cannot view any specs for the OPT or PT but they are all toroidal. I
have seen many really horrible toroidal OPTs which have been designed
and wound by morons who have not used sufficiently thick insulation
betwen P and S windings which results in far too much transformer
shunt capacitance. Judging by the advertised LOW prices methinks its
probable the whole range of amp kits or the main parts are all made in
China. Unfortunately, the Chinese have some way to go before I can
endorse most of their audio frequency transformer integrity.
I'm sure knowledgeable ppl might find more to criticise but with minor
modding one could probably greatly improve the product.
was that K404 or K4040? *I found this:http://www.vellemanusa.com/us/enu/pr...iew/?id=350535
The K4040 at the link you just quoted did not have the schematics,
just kit details in 4 languages.
The K4040 looks like the K404. Or did I leave a nought out?
If it would be necessary to modify such a kit for better performance, it
sort of makes the case to just publish an easy-to-build reliable
schematic, chassis layout, and parts list and then convince a single
distributor to offer it as a "kit". *The chassis seems to be the biggest
limiting factor here (somewhat expensive per-unit to do a limited run,
lots of uncertainty on stocking completed chassis, etc.). *Convincing
Velleman to offer an upgraded version of their kit might actually be
cheaper.
(I have a nice big roll of 0.1" 63:37 PbSn WRAP and I'm not afraid to
use it)
Without seeing the Velleman on my bench and examining it, I don't know
what I might think about the build quality.
But in a manual I did find elsewhere the schematic was given and I
thought some changes would make considerable improvement.
What Andre says in favour of Velleman may be 100% correct and
certainly the price is good.
With a quad of EL34 in PP one can indeed get superlative performance
without ever moving above the class A to AB threshold.
At listening levels which will never cause a divorce the THD is below
0.03%, providing you have at least average speaker sensitivity of say
90dB/W/M.
One wonders how a kit can be prepared for the price and still generate
a profit, hence my concerns that parts are sourced from China. Not
everything from China is crook though. So let's not assume anything.
Its just that I have had a number of Chinese made amps land on my
bench for drastic surgery to remove the inbuilt fire crackers so
blithely included by our Chinese friends....
Patrick Turner.