FYI, those actually look like Mullard made CV6. I am positive at least one of them is a Mullard Mitcham with the D code. The GEC will have stapled plates with 2 rectangular holes on each side.
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Cayin HA-300MK2 (2022) TOTL Transformer coupled Direct Heated Triode Tube HeadAmp (Page 91)
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JeffMann
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There is another reason that I think that they could be Mullard CV6 tubes.
The metal wire piece connecting the caps to the anode/grid are thick and weighty and look like flat-strips.
The GEC CV6 tubes in this listing have thin round wire connections.
https://www.ebay.com/itm/202582373728?hash=item2f2ad9b560:g:Z1MAAOSw9eVcUtVI
Jeff.
dynamic headphones
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i have a problem with my ha-300. i can hear a very loud white noise which interrupts my music listening very clearly. are there any ways to get rid of this? i am using stock tubes and this is happening with my hd800s.
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You are correct, and that is another trait that differs between the two. There are several other little differing traits as well, but I think the plates are the most obvious thing to look for.
For those that are curious, here is what the two brands plates look like side by side.
Left to Right - Mullard Mitcham CV6 from the 40's, GEC Shaw CV6 from the 40's, and GEC Hammersmith CV1135 from the 50's
Notice the plates on the Mullard are welded (no holes) and on the GEC's they are stapled (4 rectangular holes). They are also shaped differently, with the Mullard being flat and the GEC being rounded in the middle. They are definitely different, and it's quite obvious when you know what to look for.
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Ysound
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Which is better out of the 3?
They are all equal, but different enough to own them all. I plan to do a thorough write up comparing them all soon.
jonathan c
Headphoneus Supremus
** a back of the tube box summary will do
Ysound
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Wonderful, looking forward to it.
How about this. . .** a back of the tube box summary will do
Mullard Mitcham CV6 - The best mids I have ever heard. The bass is super impactful with a bit of middbass bloom to keep things warm, with smooth highs. This tube is the Mullard house sound done right.
GEC Shaw CV6 - tighter sound top to bottom with better treble extension and transparency compared to the Mullard.
GEC Hammersmith CV1135 - takes things even further toward neutral/transparency compared to the Shaw CV6. This tube also has the most open and largest staging.
More detailed impressions to come, with several other tubes from the same family. . .
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, ‘wes’ is more !
JeffMann
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I noted that your adapter is angled at about 45 degrees relative to the front of the amp.So, as good as the Mullard (Mitcham) CV6 is. . . the G.E.C. (Shaw) CV6 is definitely just as good.
The Mullard (Mitcham) CV6 is all about the mids, and they are absolutely fantastic. The G.E.C. (Shaw) CV6 on the other hand, has stellar transparency, and excellent extension on both ends. The Mullard has replaced the RFT 6SN7 and the GEC has replaced the Melz 1578 in my tube collection, and I could not be happier. I think it's nuts how much cheaper and better the CV6 is compared to the 6SN7, and I sure am glad I took a chance on them.
I have a few more different versions of Mullard, GEC, and some Russian made ones from the 50's on the way, and plan to do a comparison of them all once they are all burned in and I have a good feel for them.
More to come. . .
Does it come that way or did you have to perform some process to rotate the adapter?
Jeff.
The HA-300MK2 is a transformer-coupled vacuum tube amplifier, therefore the headphone outputs are coming from the output transformer and carry too much current to be used as a pre-amp. You can get it to sound at the volume you need, but the performance will be way below what you should expect from a pre-amp at half the price.
Is this your first tube headphone amplifier? Are you familiar with the routine procedure to debug the interference of a tube amplifier? Can you tell us the complete audio chain? Any WiFi devices nearby? Are the interconnects properly shield? Can you test your system without any USB connection, just to determine whether USB noise is part of the cause? ....
If you are unfamiliar with tube amplifiers, I can tell you in advance that the interference can come from all sorts of places that you couldn't have imagined. Someone replaced his USB keyboard and eliminated the interference accidentally and then we find out the backlight of his previous USB keyboard is causing the interference.
I am in the middle of sick leave right now, so please share as much information as you can here, I am sure other HA-300 users will help you out, this is a very helpful user community.
dynamic headphones
100+ Head-Fier
thanks for the lengthy reply. this is not my first tube amp but it is my first dht 300b amp. i have tried:
1. reseating the tubes, switching them from left to right.
2. my interconnects did not cause this issue on other amps.
3. wifi devices nearby, however the noise that they have generated in the past is not like this at all.
4. my usb is isolated, this is not usb noise.
the noise i would describe as a white noise, it is constantly loud and it does not seem to get quieter after the tubes have been on for a while.
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Hope you feel better Andy!
Just throwing this out there, and some tube amps respond differently to external factors, and what worked for one may not work for another. For instance, my router was on the ground in the room next to me, and did not mess with my previous tube amps, but was causing white noise/intermittent static in the right channel with my HA300MK2 until I moved it to a higher location. I would check everything possible, and even stuff that did not cause issues with your other amps.
I had to really hunt it down, and never would have guessed my router in a completely different room would be an issue. Now that the router has been moved I am noise free and loving every second.
Good luck and I suggest reading through this thread a bit, to learn what has and hasn't worked for others.
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