• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

£49.95 Tube amp?!

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You'll probably find that underneath the box that looks like it should house OTs, there is a single toroid mains transformer... ;)

Take a look at one of the other amps listed by the same vendor... the words "Hybrid" were added AFTER the vendor appeared on this forum to extol the virtues of the same amplifier. SAV-400A Vacuum Tube Integrated Power Amplifier 2X35W on eBay (end time 20-Feb-11 19:07:28 GMT)

The actual amplifier delivered (the SAV-400A) has no output transformers, no line out (as specified in the description) and on the whole was pretty shoddily made. I know because I bought one :eek: , albeit MUCH cheaper than the listed price. My own example has since had ALL the innards removed and replaced by a pair of point-to-point EF86 pre-amps. Even the "Real wood" description about the colour is misleading. The "real wood" is MDF... :rolleyes:

So why did I buy it? Marketing hype and gulibility on my own part. I've since joined this forum and learned an awful lot more than I knew when I hit the "Buy it now" button... ;) Hence my sig line.
 
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That would be me.....:)
:D

I reckoned the same when I bought the SAV-400. But it actually looks quite good (I'm in the process of replacing the MDF bits with German white oak). At the time, I rationalised that it wan't too bad a price to pay for a chassis if you want to junk the innards and build a real amp into it. Again, I've since discovered suppliers such as Bluebell Audio... :rolleyes:
 
Hi,
it makes you wonder how many people have been caught out with this sort of thing. Does it break any "Trade Description" laws?
Dragondreams; I think you being generous with the notion that it is a toroidal tranny under the hood; I'll bet its just an EI
I wouldn't touch one with a barge pole although like you say it might be worth the money for the chassis and parts.
 
I know because I bought one :eek:
Thank you for sharing your experience! This item is a very bad joke for buyers who not familiar with audio schematics especially.

I hate such kind of scum on eBay. I must admit that Audiogone a way better spot for purchase.

BTW LM1875 sounds excellent to my ears so it might be a good kit since you have already tubes in sockets and filament as well. It needs Just additional hi voltage trafo and two 6N1P could be combined as mu-follower for an input stage.
Might be sweet sounding hybrid amp eventually.
 
Might be sweet sounding hybrid amp eventually.
That was my thinking when I bought the SAV400. At least most of the parts were there.

The drawback (to my mind) is that the valve bases (tube sockets) are the PCB mounting type. This narrows down the options for modification.

I originally intended to convert the amp to a single ended stereo amp using an EF86 driving an EL34 in each channel. Unfortunately, there just wasn't enough space to fit the required transformers. SO I changed tack and converted it to a pair of stereo pre-amps instead, using four EF86s.

I ended up cutting a copper sheet to size and punching holes to accept "free mounting" valve bases and bolting this to the underside of the chassis. It also gave me a convenient anchor point to affix the smoothing cap board to.

To be fair, I didn't even listen to the amp before I gutted it. It may have sounded quite pleasing, but it certainly wasn't what I'd consider to be a "tube amplifier"... ;)
 
I can confirm it is a hybrid. I owned one of these. They are actually pretty nice sounding after a couple of small mods and some bed-in time.
They are LM1875T output chips, so power is only 25w into 4 ohms, 18w into 8 ohms.
They have the power toroid transformer under the cover on top (which is actually MDF). If it hums, it probably means the toroid has a crack in its core, so beware as that drops its efficiency quite a bit.
Still, 240/16-0-16 transformers are available, and at that price (which is similar to what I paid) they are actually a nice unit.
The valves are in circuit as followers, but running on a total HT of 24v they don't do much other than add some THD to the signal.
Main problems:
Poor quality front panel controls, especially source switch.
Valves are overheated because their supply is half-wave rectified off one side of the 16v transformer (easily fixed buy adding two more rectifier diodes in series with the one that is currently feeding the filaments.

Gary

EDIT: I notice the one on ebay has a rotary source switch so they must have changed since mine had a (poor) toggle.
 
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