Audio, hi-fi and car audio - How about this amplifier?

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How about this amplifier?

Justin wrote:
Hello everyone! I am a newcomer to the world of tube audio. I've
loved my Peavey Classic 30 guitar amplifier for the last 6 years and
I'm looking into getting started in the world of tube stereos. I know
a little bit about amplifiers (I'm a recent EE grad) and I collect
vinyl as well.

I'm considering purchasing the amplifier listed he

http://cgi.ebay.co.uk/Nice-300B-6CA7...QQcmdZViewItem

Yo, Justin, welcome! Don't let the choleric mouthfoamers like Wilson
put you off; they count it a day wasted in which they don't ruin
someone's pleasure in being alive.

The amp you want to buy is a bit expensive by Chinese standards. Go to
the newsgroup uk.rec.audio and search for posts by Keith G. He has
bought several Chinese amps and he shows photographs and gives prices
on his site. I seem to remember he bought in Germany; your advertiser
must have quite a few bad responses from customers, so I would view him
with care; I have good experience buying from Germany myself (not amps
because I build my own but other stuff).

If you want a US built amp, how about building it yourself? Go to the
site of Electronic Tonalities of Poulsbo, WA,, who sell good kits, and
have a look around. I built one of their original SEX kits and found it
good.

The thing about buying or building a small amp is that it can easily
turn out to be a misery unless you consider your speakers first. At my
site JUTE ON AMPS
http://members.lycos.co.uk/fiultra/JUTE%20ON%20AMPS.htm
you will find a lot of information about how one decides which amp to
buy or build, including a lot of background about 300B amps in THE KISS
AMP
http://members.lycos.co.uk/fiultra/T...mp%20INDEX.htm
A pair of chapters you must absolutely read before you buy an amp, or
speakers for that matter, is The Myth of the Watt
http://members.lycos.co.uk/fiultra/K...dre%20Jute.htm
Calculating the Power your Amp requires to Drive the chosen Speakers
http://members.lycos.co.uk/fiultra/K...dre%20Jute.htm
The Impressario is an inexpensive, easily built, point source speaker
that requires less than 2W to sound great:
http://members.lycos.co.uk/fiultra/K...Impresario.jpg
and here is an a very inexpensive 2W ZNFB SE amp I designed for my son
when he was a student
http://members.lycos.co.uk/fiultra/Jute-EL34-SEntry.jpg
which you can build with the inexpensive US-made UBT or Hammond output
transformers.

Follow your nose and your heart. Hi-fi is only a hobby, not a crusade.
The single-focus fanatics will leech all pleasure from your hobby if
you let them. **** 'em.

HTH.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

I was drawn to this amp because it is integrated (I don't currently
have the funds to purchase a
preamp and power amp combo - but I would like an all-tube sound),
class-A, has all-tube
rectification, point-to-point wiring, and comes with electro-harmonix
tubes in the preamp stage.

Does anyone have any thoughts or opinions about this amp? I realize it
is Chinese and a USA-made amp would be better, but of course this
contributes to the lower price. I also realize I will probably have to
purchase a phono preamp to hook my record player to this amp
effectively. Anyway, suggestions/opinions/criticisms anyone?

How about this amplifier?

Bret Ludwig wrote:
snip

Far far far better to buy a not working old amp of US make (if you're
in the US) or to build a classic Ike/JFK/MM era design using known
good output transformers of US, Brit, Swedish or Jappanese make. Most
Chinese tube finished products are unmitigated dog****.

If you are in the UK first, get Morgan Jones' books and read them then
see if you can find a German title called
"Audio-und-Gitarrenschaltungen mit Rohren" by Rainer zur Linde.

Build the RIAA preamp in this book if you are into vinyl. It will
directly drive most any tube stereo amp as long as you put a volume
control on the amp (that way it's a "integrated line stage") with no
preamp per se. It is a better sounding and measuring phono stage than
anything available from classic vintage units or from ARC, VTL, cj, or
those other size queens.

Sowter in the UK is a good transformer supplier and I would buy from
him.

How about this amplifier?

"Andre Jute" wrote in message
oups.com...

Justin wrote:
Hello everyone! I am a newcomer to the world of tube audio. I've
loved my Peavey Classic 30 guitar amplifier for the last 6 years and
I'm looking into getting started in the world of tube stereos. I know
a little bit about amplifiers (I'm a recent EE grad) and I collect
vinyl as well.

I'm considering purchasing the amplifier listed he

http://cgi.ebay.co.uk/Nice-300B-6CA7...QQcmdZViewItem

Yo, Justin, welcome! Don't let the choleric mouthfoamers like Wilson
put you off; they count it a day wasted in which they don't ruin
someone's pleasure in being alive.

The amp you want to buy is a bit expensive by Chinese standards. Go to
the newsgroup uk.rec.audio and search for posts by Keith G. He has
bought several Chinese amps and he shows photographs and gives prices
on his site. I seem to remember he bought in Germany; your advertiser
must have quite a few bad responses from customers, so I would view him
with care; I have good experience buying from Germany myself (not amps
because I build my own but other stuff).

OK, see below....

I was drawn to this amp because it is integrated (I don't currently
have the funds to purchase a
preamp and power amp combo - but I would like an all-tube sound),
class-A, has all-tube
rectification, point-to-point wiring, and comes with electro-harmonix
tubes in the preamp stage.

Does anyone have any thoughts or opinions about this amp? I realize it
is Chinese and a USA-made amp would be better, but of course this
contributes to the lower price. I also realize I will probably have to
purchase a phono preamp to hook my record player to this amp
effectively. Anyway, suggestions/opinions/criticisms anyone?

I'm afraid I've taken my webpages down (needed the webspace for speaker
stuff) but I can tell you that amp is very similar to one of the two Chinese
300B SETs I bought - same chassis, apparently same (or at least same sized)
transformers but different input/driver valves (mine are ECC81/6V6).

It is the same supplier who, I believe, is well-established with an emporium
in HK or somewhere and is perfectly reputable AFAIK - there were no delivery
problems with my amp. Shipping to the UK was about 100USD (from China - the
amps from Germany were entirely different) and the same again for Import
Duty, so the price goes up a tad!

My opinion of the amp is that it is perfectly *adequate* if possibly a
little unspectacular (it don't beat my homebrew 2A3 LW), it appears to
reliable (mine is performing perfectly well) and is undeniably very good
value for money. But, in case you are interested, I would say the Bez amps
will give you more bang for the buck but they will almost certainly mess you
around a bit - if nothing else, they seem to come with some seriously
deranged valves in 'em!! ;-)

These budget Chinese amps do get you into the SET game on the cheap, but my
tip would be to follow André's advice and build your own - it'll probably
cost more, but as an EE grad, you owe it to yourself (do you not?) and any
amp you build yourself will probably sound better) and it will give you much
more satisfaction!!

How about this amplifier?

Keith G wrote:

you owe it to yourself (do you not?) and any
amp you build yourself will probably sound better) and it will give
you much more satisfaction!!

AGREED!! There's no better sounding amp than the one you build
yourself. It's not that hard to do.

Regards,

Raymond

How about this amplifier?

"Raymond Koonce" wrote in message
news:w0dAg.8264$ok5.4613@dukeread01...
Keith G wrote:

you owe it to yourself (do you not?) and any
amp you build yourself will probably sound better) and it will give
you much more satisfaction!!

AGREED!! There's no better sounding amp than the one you build yourself.
It's not that hard to do.

Yes. Those are my sentiments exactly, although knowing where to start
is something of an enigma:-)

It's not rocket science, and as an EE, Justin, you should have
no problems technically.

SET sometimes takes a lot of stick (especially on UKRA)
but there are many good schematics, and people
(especially on RAT) who will point you in the right
direction if required. There is a great deal of know-how
here, and (contrary perhaps to appearances:-) some very
friendly and helpful people.

Justin. Don't be discouraged by those who would disparage
valve/tube audio. Build some equipment, and form your own
opinions. It takes a lot of dedication, as Patrick, Andre, Nick and
others will tell you, but it is quite within the realms of possibility
to build something to equal the products of the major manufacturers.

Welcome to RAT. Hopefully you will keep us posted as your
ideas turn into reality:-)

One of my homebrew efforts can be seen at:

http://www.kolumbus.fi/iain.churches...em/C50_002.jpg

http://www.kolumbus.fi/iain.churches...em/C50_010.jpg

Good luck

--
Iain
www.kolumbus.fi/iain.churches

How about this amplifier?

Justin:

Beware of advice from this particular source, some salt is required.
The amps from the perpetrator of this site don't work. Do a search on
this NG for the history.

That being written, some advice from a Fix-It type:

a) Chinese amps tend to be of minimal quality, and so become attractive
primarily to the price-driven. I am presently rebuilding a pair of
guitar amps for a friend that were awfully cheap (single-ended
6BQ5-based units), but each needs a substantial circuit rebuild to
remove the hum at low volume and the whistle at higher volume. Go
figure. It's only a couple of bucks worth of parts and a couple of
hours time, but there should be no need for it were the amps designed
properly from the factory.
b) I boggle at the concept of purchasing an amp under 'sales-final'
conditions unheard. Sure, at a flea-market at a cost similar to a
Mocha-Latte-Grande at Starbucks, but not for real money.
c) Building it yourself is a worthwhile endeavor. But given the very
real problems with SET amps, coupled with the very real problems with
tube amps in general, I would strongly suggest that if you choose this
option, you start with an established and proven source and an
established and proven circuit requiring a minimum of test instruments.

d) And what is your goal? Do you have speakers that are compatible with
a flea-powered amp? Do you enjoy music that is sufficiently 'simple' to
be compatible with both? Is it the concept of SET that is appealing?

Yeah, yeah... we purchase on emotion and justify afterwards. But the
potentialf for Buyer's Regret should at least be minimized.

Peter Wieck
Wyncote, PA

How about this amplifier?

Trevor Wilson wrote:

"Andre Jute" wrote in message
oups.com...

Justin wrote:
Hello everyone! I am a newcomer to the world of tube audio. I've
loved my Peavey Classic 30 guitar amplifier for the last 6 years and
I'm looking into getting started in the world of tube stereos. I know
a little bit about amplifiers (I'm a recent EE grad) and I collect
vinyl as well.

I'm considering purchasing the amplifier listed he

http://cgi.ebay.co.uk/Nice-300B-6CA7...QQcmdZViewItem

Yo, Justin, welcome! Don't let the choleric mouthfoamers like Wilson
put you off; they count it a day wasted in which they don't ruin
someone's pleasure in being alive.

**Why? Have you heard that amp? Do you advocate that people should spend
money on products they've never listened to? You're dumber than the original
poster.

Never buy a car without test driving it, never marry a woman without first
bedding her and NEVER buy audio equipment without first listening to it. Of
course, a moron might suggest that I am wrong. Sane people will always
disagree with you.

The original poster could audition just about any 8 watt amp with 300B SET outputs
to get an idea of what is possible with 8 watts.

I am sure he could find a sample, or join an audio club to find out more.

But I do share Trevor's concerns about the chinese build quality.

Quality is something the makers of cheaper chinese don't understand like the best makers in the West.

But one has to expect this situation to be quite normal because if they are prepared to make
an amp for 20dB less $$$ than a CJ or ARC, then expect 20dB less quality.

Its about that simple.

Anyone buying Chinese Crap may need to have it modded.

About 3 weeks ago I had to repair a chinese amp from Hong Kong with
the brandname printed on the front "Hi-Fi Amplifier", which isn't a brand name.
The guy here who bought it for peanuts direct from HK got it cheap because no western middle men
upped the chinese price by 15dB.
Anyway, it lasted 2 weeks before one channel became silent.
I easily fixed it by replacing a 25 watt common cathode resistor to the two KT88 output tubes of one channel.
There was no paper work with the amp and no schematic available anywhere.
I found it difficult to trace the point to point circuitry because parts had been thoughtlessly
placed so that tube socket tags were obstructed from view, and couldn't be soldered
unless some parts were removed.
To remove the faulty resistor I had to break off bolts because the screw heads were obstructed by
the double layered steel chassis used to enable about 6 different models to be assembled
similar to the one which is the subject of this thread.

So replacement of an OPT or other part including a tube socket would take 30dBb longer than it should.
The amps are not built to be serviced easily, and as usual, contain no active protection measure should there
be bias failure of one or more output tubes.
The power transformers hummed badly, and were not silent as they should be.
There were two power trannies wired in parallel, and with 3 dual diode rectifier tubes also
wired in parallel to act as a slow turn on diode, with SS rectifiers.
It was supposed to be dual monbloc but wasn't.
As well as the gimicky 3 rectifier tubes where one would have been OK there were 2 tuning eye level indicators
which had numbers and chinese lettering and about which I could find no data on th web.
They indicated clipping at about 1/4 of actual clipping output voltage.

Good amps don't have gimicks.

The volume control pot and source switch was the usual crap $2 type one sees in cheap
shops selling such crap.
And its a nightmare to replace such items and any of the rear panel RCA sockets etc
because there is a stupid 10mm thick anodized Al panel screwed on from inside the amp to cover
any nuts or screws allowing one to replace these items.

Somebody with NO brains designs these amps which are designed to look good,
and easy to assemble, and horror story to service.
The powder coat finish was very ordinary.

The amp was UL, and made the correct 50 watts AB but there was zero NFB so the output
impedance was 10 ohms. Although the OPT had enough bandwidth with no NFB, they howled
with signal and showed that they were not properly potted and maybe not varnished properly.
The quality of circuit layout left a lot to be desired although it looked well if you had no idea about detail.

After the small mods I made to the KT88 output tube cathode circuits by using
separate R&C bypassing to each of the 4 KT88, I then converted it to triode operation and
Rout fell to 2 ohms at the 8 ohm outlet.
There was still very adequate output in triode to suit the owner's speakers from either the 4 ohm outlet
where Rout = 1 ohm, and from the 8 ohm outlet.

The 4 ohm outlet ensured class A power was around 12 watts, with slightly more in class AB,
so the amp ended up about the same as a standard 16 watt Williamson with KT88 in triode
which is the better tube to use in a Williamson, and not as much NFB need be used, and in fact
because the wacko weirdo chinese input circuit would have taken too much modding
to accomodate 12dB of loop NFB, I left that job out and left the amp without global NFB.

The owner is delighted. He now gets better HF with his Quad ESL57 because these speakers have declining
Z at HF which don't suit being driven with an amp with Rout = 10 ohms.

I would predict that perhaps another branch of rthe HK company who made the amp I
repaired may make Guchi handbags and Rolecks watches.....

But the one I repaired looks very much like the one mentioned in this thread.
It has very similar details both above and below the chassis.
I'd never buy one of course.

Photographs of chinese crap on E-bay do not show up the faults many of the
amps.

But if price is all that matters then then the Chinese are unbeatable.

And at the end of the day, the Chinese cheap amp is no worse than the crap
that was foisted upon us by unruly western makers in 1955.

One hardly has to try very hard to make OPT and power trannies better than the cheap horrors
sold by Ferguson and others here in Oz, and ones fitted to Leak amps in the 1950s.

The chinese are merely regurgitating all the past craperama without having learnt from the past
and I wish them well should they try to improve.
Its unfortuate that had the amp I fixed been built to a similar design to a Leak
in terms of chassis construction and wiring detail, it would have been a lot cheaper for the Chinese
to make! And it would have been better than a Leak.
And if the Chinese ever learnt a little more about transformers and circuitry
and parts quality they would indeed get more respect from discriminating audiophiles
all over the world.

Patrick Turner.

--
Trevor Wilson
www.rageaudio.com.au

--
Posted via a free Usenet account from http://www.teranews.com

How about this amplifier?

The original poster could audition just about any 8 watt amp with 300B SET outputs
to get an idea of what is possible with 8 watts.

I am sure he could find a sample, or join an audio club to find out more.

But I do share Trevor's concerns about the chinese build quality.

Quality is something the makers of cheaper chinese don't understand like the best makers in the West.

But one has to expect this situation to be quite normal because if they are prepared to make
an amp for 20dB less $$$ than a CJ or ARC, then expect 20dB less quality.

How much should one pay if the price is "20 dB less"? Are you using
money as power or voltage?? Either way we would be talking about a
bargain just for the chassis and power transformer, wouldn't we?

ARC and c-j are very overpriced and not terrifically well made, and if
their feet were held to the fire on quality and consistency I bet the
Chinese could make a pretty good tube amp for a few hundred dollars.
But they aren't, because there is no traceability, no consistency, and
the end buyers are idiots, and so they don't.