Anyone tried one of these Chinese babies? I ordered a kit from eBay for the hell of it.

What are you hoping it will do for you?.

Probably trying to flog a few with a tenuous question on here.

I once built a valve amp - it was tremendous but not toddler-friendly so it had to go unfortunately. Can't say I miss it, even though it's back from uni now for the summer.

Nah, I always liked my hifi but I live on a boat now so no room. My current set up is quite nice but a bit digital. I'm hoping that by feeding the line out from my dac into it may warm it up. I know you audiophiles will pooh pooh it but hey...it was 20 quid and only a punt.

Well the valves might warm the room up. But I doubt they'll do much for the sound

What make you say that Chris?

Just because it has a valve in it does not make it a super-duper HiFi device. It is just as easy to design a really crap sounding valve amp as it is a transistor one. Some of the comments I have seen about some of the cheaper variants of these valve kits (and there do seem to be a load) don't fill me with much confidence.

I've seen criticism of some designs saying they are wide open to RFI for example due to poor input design. Other people have criticised aspects of the design such as exposed 170V DC supply rails that could give the unwary a serious belt.

A common criticism seems to be a lack of instructions so unless you are reasonably familiar with electronics you would struggle to build the kits properly.

All in all I wouldn't be expecting much from a cheap and possibly not so cheerful kit as some of those I've seen on e-bay.

I hear what you're saying, the one I've got is the expanded Matisse cct, if the components are as good as they say it'll be an interesting experiment tho. I've read good and bad but for the price of a night in the pub....

It's something to play with, and fun to build (presumably?) - I've built a LOT of Chinese kits over the last year or two.

However, adding a valve will only make your sound worse, greatly increasing distortion and noise, and giving a much poorer frequency response - but some people seem to like the inferior sound (presumably taking them back to the 'bad old days' ).

Dudes! My favourite system went...

Marrantz for the digits, NAD for the boost and Mission for the electrical to noise conversion. My current set up lacks that thing that you can't put your finger on.

Love from a broadcast engineer with 20 years of experience that doesn't need condescending advice from glorified TV salesmen.

If you've only got 20 years experience, and none of that in HiFi, then you've missed out on knowing about valve audio

The beauty of valves is in the way they move electrons.

As there are a few of us broadcasting engineers on this forum, mainly retired, could I ask you where and what you have been working on recently. You do not have to name the actual company of course if you do not wish to but we are always interested in information on current broadcasting practices.

Many valve circuits in the past added second harmonic distortion which some people find pleasant. I don't know if that is the effect you are looking for, only trial and error will tell.

At least they are dead simple to understand how they work

So is a MOS-FET

I could build a valve - I doubt I could build a MOS-FET

That's as may be, but you only mentioned understanding them, not building them.

I have a valve amp, home made with a gz34 rectifier, 6sn7s feeding mazda pen45s as the output bottles in push-pull. Sounds good !

When I started in electronics in the early 80s, my instructor said " this is a valve" *** holding one up**" they are now defunct and we will only spend a day on their theory" - and we did!
I learnt all about them in the following years but no longer bother repairing valve stuff , except for a Hacker record player for a friend that needed recapping. ( horrid tone circuit on them, only got a treble cut control , not boost ) anyway, I digress..

I've seen those EM84 magic eye vu meter kits on ebay- I fancy making one up and fitting it into the fascia of an old hifi seperate , or something lol

I went on a broadcasting course and the instructor put an image orthicon on the table then looked around to see how many people knew what it was.

Nearly all portable record players had treble cut tone controls back then. In the rare instance they had a bass control it was often just cut as well.

Back at college in the early 70's we didn't cover valves at all - except part of ONE day, and that was because the normal lecturer wasn't there, so the replacement one did a little on valves. Bit strange really, as almost all the sets that we worked on at college were mainly valve ones, and the rest of the week at work there were still lot's of valve gear about.


As already mentioned, that was perfectly normal - and in fact Hacker were one of the very few who did often fit 'proper' tone controls as we understand them today.

I had a Rogers amp and in addition to the normal bass and treble it had a 'Slope' control which, if memory serves, was a variable top cut filter.

That wasn't a 'record player' though, amps commonly had better tone control systems than record players, and Rogers wasn't bad gear at all. I've repaired a few Rogers items in the past.

The 'slope' control was probably for helping to reduce scratches from records, and hiss from tapes

Leak I think made an amp with the name Varislope, you set the treble filter cut off frequency and then the rate of roll off on the slope control for best results. As Nigel says it was for hiss and scratchy records. Happy days, long before digital.