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A brand new tube amp for under $100? - Nahhh...

The Digitech may have a faulty volume pot, or at least thats what I thought.

It seems that the hum I can hear tends to dissapear, or is almost ignorable, when the volume is above the 9.00 o'clock position. Then I decided to try a passive pre (HH style) on the line in, hoping to drop the level on the input, so I could run it turned up a bit.

If I turn the volume up, with a lower input, I still get the humm at lower volume levels. I have tried 3 set of speakers, the result is the same on all sets.

This seems odd to me. It seems to be related to the output level, not the input level. Is this possible?

It's been going well, other than the hum, for about 3 weeks now.
 
Celt said:
Kind of reminds me of the "white van" speakers that pretend to be something they're not.
The "Digitech" name on a "tube" amp and the fact they wasted four valves just to make it pretty is damn funny IMO.
Click to expand...

Yeah. I could have done it in three. :D
 
I like the fishing here. You can always get a bite.

I laugh is always good, but not very helpful, mate.
 
Hi,

How is everyones Jaycar valve hybrid amp going? Has anyone change there voltage on the heaters? what was the result? : Has anyone changed there valves what was the outcome - better sound?

A bit of confusion - 6N1 what is the direct comparison - ECC 40 or 85 or 88. Which would you change first for a better tube the 6P15 or 6N1.
Would you change the 6p15 for a electroharmonix el84 or sovtec or JJEL84

Cheers

Steve.
 
Currently I'm working my way through the original link at cool386 to reduce the voltage on the valve heaters to 6.3v, using both halves of the transformer secondary and adding an extra diode and 3R of resistance (10W).
Yesterday, after getting this amp out for the first time in over two years (its had less than 4 hours on time) I replaced the LM1875 chips with my preferred TDA2050V. The amp sounds much the same, but bass is quite a bit more defined. I dare not run it too long until the heaters are sorted!
 
OK, a couple of spare hours on a soggy Sunday morning later and I'm listening to the fruit of the labours on this amp whilst typing this. I decided to follow the precise instructions on cool386's page, so purchased a tag board to populate with the 2x1N5408 diodes and 4x1.5R 5W resistors he recommends. Once done I isolated this board to one side panel of the amp where there was enough space to stretch the feeds from the transformer secondaries. I chopped the two thin cables connected to the valve heaters - with no understanding of valves at all apart from some basic guess work on the heater pins and info on wikipedia - and connected these to the outputs from the diodes.

Putting the amp back together and turning it on, the valves glow noticeably less though the super bright led on the on switch has so far defeated my best efforts to calm its laser-like output with resistors. I think I'll ditch it for a nice low output led and perhaps change the colour to orange. I was also spying the valve sockets to see if it might be possible to fit some bright orange leds underneath each valve a la chinese amps latest approach - but looks like no hope with those metal inserts. The sound is actually pretty detailed with no particular emphasis on any frequency, if a lot more up-front than I'd have imagined.

My one remaining question is whether the valves really contribute anything.
 
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Why not just buy a pair of somethng like the Grommes Little Jewels and repair as necessary? Or, a tube console pull like a VOM or Magnavox. Even a Heathkit or EICO? Just remember that if it sounds too good to be true, it usually is.
 
Could anybody help me out with the user manual for this Chinese hybryd tube amp? It is sold in Holland as Mistral MM1. I bought one second hand, love the sound but have no manual.
 
Tl;dr

Digitech is a brand that is sold here in aus by a big electronics chain I have many products they seem to be good. I am typing this over a digitech wifi usb device atm lol.
 
Not for me!

Cool looking little amp, but you can have it. I can understand why someone would want to buy it and play around with it. If you have the time and the expertise, then fill your boots. I don't have the time and patience to arse around with something like this and still have a piece of crap when I am done investing in it. I have single tubes that cost more than this amplifier! :D I can't see there being $100.00 worth of parts in it, because no one in their right mind would use them in a quality build.

Anyway, have fun with it - after all, that is why you bought it, and it is your money and time. I am just saying that it is not for everyone.

ken99
 
I guess any discussion on this amp is fairly pointless, as there are probably so few still working. I will say that I regularly slot this amp back into my main hi-fi because even though it is not as accurate or precise as my SS amps, it really engages. It is impossible to leave it on for extended periods as the thing gets extremely hot after 1-2 hours, especially at the moment. A look under the base cover shows there are scorch marks on the side of the 5W resistors. The long-term recommendation from cool386 was to wind some extra 6.3V secondaries on the toroid instead to feed the heaters which would be well beyond anything I'd be comfortable with attempting. I'm thinking of using some 25W or even 50W ARCOL resistors in their place, which might dissipate the heat better.
 
Yes mine is still going fine. Got some mods done, lowered the heater amp, got new valves. So musical puts a lot of S amps to shame for musicality. Cheers Steve.
 
The first DVD player I ever owned back when I was fresh out of high school was a Digitech branded unit. It lasted for a few years and had features the big brands didn't offer for quite a few years afterwards. Likewise, I'm currently running a Digitech DAB+ radio. Not too many affordable DAB+ radio's available in component form, it sounds good and works well.

Pretty sure I've seen that little amp being sold on eBay under another brand: "Nobsound". Terrible brand, inspires even less confidence than the Digitech brand.
 
DigiTech (not the same) is an American company that manufactures guitar effects. I'm surprised the Chinese can get away with selling their product here under the same name.
 
hi guys, I am thinking about getting a set of cans for my main in the living room, Pioneer SX1250. I read where you really need a separate amp for the cans to sound great, I don't know how that works, will it plug into the 1250 ? anyway I went to ebay and put in headphone tube amp and this little unit came up, Nobsound MS-10D MKll for 100 bucks, it LOOKS really cool, wood sides match the 1250. It seems this thread is about using it as a main which is getting bad reviews, what about using it just for cans ? or maybe someone can point me in the right direction. I am new to the can can thing and havnt even bought mine yet but looking at some Senn's or Grado's, thanks, Roost
 
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