Dougie2404
cranky old git
Yeh , mine was the same Rock Grott mods with,,,,,no I don't remember if the valves were changed or not 6922's I think r maybe ecc83's but I'm guessing.
Valve buffer stage
- Thread starter drummerman
- Start date
tuga
Legal Alien
The truth is that you were masking the shrillness somewhat whilst reducing channel separation, adding a bit of harmonic distortion and raising the noise-floor when you should have addressed the cause of the shrillness in the first place, by replacing the CD player for a better unit, but making sure that it wasn't the amplifier or the speakers causing the problem.
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There is a lot of good information in this thread. I bought one, but unfortunately short-lived in my system...
I bought: https://www.amazon.co.uk/dp/B071VSTDQY/?tag=pinkfishmedia-21 a few months ago as a fun purchase to put between my Tisbury Domino head amp and Quad 306. Results were amazing: not only did the sound have more body compared to the Tisbury passive previously used, but fascinatingly, I felt that as well as more PRAT, the system 'phrased' better - the different musical threads made more sense, as if they were talking to each other. A CD of Les Quatuor Mosaiqes was a revelation, suddenly I realised the fascination some folk have for string quartets, truly delicious to hear. So this is the valve sound eh? Here to stay!
Er no. Turning on the device one day I heard a crackle. I touched the volume control to hear a bang through loudspeakers, touching the case made another one! Pressing the off button on the Quad 306 made a truly frightening noise, before the system thankfully fell quiet. I tried the Nobsound with my Class D amp with the same effect. Swapping the power supply gave short term relief, but a nasty fizz from the system reminded me of the fallacy of wishful thinking. I hastily turned it off, and swapped the Tisbury Passive back in.
While the Nobsound was in the system, it was one of the best - and good value - changes I've made. It was truly musical. I would gladly try it again, but I lack the skills to take the device apart and find the issue that makes it, for me, a poisoned chalice. I think I will think carefully before buying Chinese cheapy hifi again!
Good luck to the OP, hope your pleasure lasts longer than mine!
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1964meb
pfm Member
Yes! When I heard a Apple Mac + DAC the cdx was sold the next week. Am v happy with that for my digital still - a good few years later. ( + jitterbug + rensen thingy)
drummerman
pfm Member
Ah, that's bad luck and sorry to hear you had trouble with the thing. - I opened mine on day 2, done in twenty secs and the soldering is very neat and component quality seems entirely ok too. I still dont get how they can do it for the money.
Since then it's been on most days, all day (and some nights too) as b/g music or BBC iplayer (fantastic with voices too). Hasn't missed a beat and I would really miss it not being there now.
Having said this, it it burns my house down you guys will be the first to know.
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SteveG
pfm Member
I was ordering stuff from Amazon anyway so added one of those Dollartek things to the order, and it's due to arrive tomorrow. I'll have a play with it at the weekend and report back!
I am expecting it to end up in the "ignore" pile with several other Chinese valve components I already have. Both of those (a headphone amp and a phono stage) have the same issue - they work reasonably well but there is a lot of hiss etc. The headphone amp isn't too bad but with the phono stage it's pretty obvious. Those at least were cheap - my final Chinese valve component was a fairly expensive CD player that's died, although at least it sounded great when it was working.
I am expecting it to end up in the "ignore" pile with several other Chinese valve components I already have. Both of those (a headphone amp and a phono stage) have the same issue - they work reasonably well but there is a lot of hiss etc. The headphone amp isn't too bad but with the phono stage it's pretty obvious. Those at least were cheap - my final Chinese valve component was a fairly expensive CD player that's died, although at least it sounded great when it was working.
George J
Herefordshire member
With valve amplification or even a valve radio, I would be reluctant to leave it unattended ... as at night for example.
Valves can run away and draw a lot of current with damage and potential fire risks long before any fuse may necessarily blow.
I had this on my Quad II Forty amp, and though it did not actually go on fire [it did blow a case fuse] it had ruined the mains transformer and took out some wiring and a resistor. Things could have been different. I had forgotten to turn off before bed. The damage was evident from the smell next morning.
My friendly electrician thinks that it is sensible to turn off everything except the fridge before bed!
Best wishes from George
Valves can run away and draw a lot of current with damage and potential fire risks long before any fuse may necessarily blow.
I had this on my Quad II Forty amp, and though it did not actually go on fire [it did blow a case fuse] it had ruined the mains transformer and took out some wiring and a resistor. Things could have been different. I had forgotten to turn off before bed. The damage was evident from the smell next morning.
My friendly electrician thinks that it is sensible to turn off everything except the fridge before bed!
Best wishes from George
drummerman
pfm Member
Ditto, I only leave it on when in and playing which is a lot as I often work from home.
These buffers run of a wallwart. The valves get warm but not hot and are cheap to replace. I have no idea how many hours to expect but probably in the thousands.
SteveG
pfm Member
BTW my copy of the DollaTek FX-Audio TUBE-03 has now arrived and I've had brief play with it in my system. I've stuck it between my DAC (Simaudio Moon) and amp (Krell KAV-400i) as I'm using an integrated so can't put it between pre and power.
Unlike other cheap Chinese valve components I've had it doesn't seem to be introducing a lot of noise, which is good. It is very much more a pre-amp than a buffer stage IMHO though, as it doesn't have any kind of bypass switch to take the volume and tone controls out. It also doesn't have any indication of what positions to use for zero added gain or zero tone control impact. My first thought then is that any positive impact on perceived dynamics might either just be down to some extra gain, or perhaps by using the tone controls to either remove room/system issues or just bias them to a way that's preferred.
I'll change the DAC in that system to one that has 2 sets of outputs (I have one lying spare at the moment, otherwise I wouldn't bother!) so I can do an easier switch between with and without the DollaTek thing to see if it adds any valve "character" or if it's just a bit of extra gain and some tone controls, then report back.
Unlike other cheap Chinese valve components I've had it doesn't seem to be introducing a lot of noise, which is good. It is very much more a pre-amp than a buffer stage IMHO though, as it doesn't have any kind of bypass switch to take the volume and tone controls out. It also doesn't have any indication of what positions to use for zero added gain or zero tone control impact. My first thought then is that any positive impact on perceived dynamics might either just be down to some extra gain, or perhaps by using the tone controls to either remove room/system issues or just bias them to a way that's preferred.
I'll change the DAC in that system to one that has 2 sets of outputs (I have one lying spare at the moment, otherwise I wouldn't bother!) so I can do an easier switch between with and without the DollaTek thing to see if it adds any valve "character" or if it's just a bit of extra gain and some tone controls, then report back.
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drummerman
pfm Member
Well, you scratched that itch ...
SteveG
pfm Member
Assuming it doesn't blow up then I'd say it's not completely useless - it could be an ok pre-amp in a small scale, single input system, so I'll probably find a use for it somewhere.
1964meb
pfm Member
Good point. I did replace the cdx with a mac book pro that left the CDX for dead in some ways (listenability being the most important)
On the Valve buffer thing - I also had a mk 3 version of the MF XD10. It was vastly better than the mk 1.