[grant0317]

So I have been using the cv4003 12au7wa brimars but they were really noisy, got replacements and while they were a bit better, the replacement tubes were still noisy. I have been sort of tolerating slight humming that comes and goes. Swapped to 12au7 mullards that came in today and they are dead silent. Idk is this a case of getting bad tubes twice or just bad storage conditions for the brimars throughout the years?

 

[Andykong]

I always thought that changing voltage from 22 to 17V means rearranging secondary windings of the power transformer. At least I read it was done when switching from 22DE4 to 25AX4GT. Not that small change imho (unless each Cayin’s transformer already has windings 17,22 and 25V)
Please correct me someone, but I consider transformers as core of tube amplifier. The rest is easily upgradeable.

We don't need to rewind the output transformer when we change the rectifier tube in HA-6A and HA-3A.

 

[DrDen]

We don't need to rewind the output transformer when we change the rectifier tube in HA-6A and HA-3A.

Naturally. I said about the power transformer only.

 

[Louisiana]

I preferred to connect the HA-3A via RCA, but since my Euforia only has RCA, I had to connect the HA-3A via XLR.
The input signal was therefore too hot for my taste, and with dynamic headphones I couldn't even go to 9 o'clock on the volume control.

To get around this, I used volume leveling in Room, as well as extra headroom of -10dB, but then the transmission was no longer bit-perfect.
Solution:

XLR Attenuator

 

[Hickory Deadglove]

I preferred to connect the HA-3A via RCA, but since my Euforia only has RCA, I had to connect the HA-3A via XLR.
The input signal was therefore too hot for my taste, and with dynamic headphones I couldn't even go to 9 o'clock on the volume control.

To get around this, I used volume leveling in Room, as well as extra headroom of -10dB, but then the transmission was no longer bit-perfect.
Solution:


XLR Attenuator

I like to have a 4 pin XLR attenuator with resistors of the same values than those used on the 4.4 out to use on the XLR output

 

[AnyDave]

I preferred to connect the HA-3A via RCA, but since my Euforia only has RCA, I had to connect the HA-3A via XLR.
The input signal was therefore too hot for my taste, and with dynamic headphones I couldn't even go to 9 o'clock on the volume control.

To get around this, I used volume leveling in Room, as well as extra headroom of -10dB, but then the transmission was no longer bit-perfect.
Solution:


XLR Attenuator

That would make me a bit nervous as there is a lot of cantilever force hanging off those XLR jacks.

I have a similar situation with multiple amps running off a DAC output and I ended up going with an RCA switcher instead, which may be a safer approach.

 

[LXMc]

Yeah, I think I'd be more inclined to try a separate xlr-to-rca converter like this J-Iso converter, or a switcher like @AnyDave suggested (even besides the additional weight hanging off the ports I don't have nearly this much clearance between my amp and the wall). I know ampsandsound has a converter also but it's really pricey.

 

[AnyDave]

Yeah, I think I'd be more inclined to try a separate xlr-to-rca converter like this J-Iso converter, or a switcher like @AnyDave suggested (even besides the additional weight hanging off the ports I don't have nearly this much clearance between my amp and the wall). I know ampsandsound has a converter also but it's really pricey.

Yeah, the J-Iso converter should work great. Radial makes solid stuff. I use their live switchers with my tube guitar amp heads, which is a much riskier application and they work great.

 

[Louisiana]

That would make me a bit nervous as there is a lot of cantilever force hanging off those XLR jacks.

This is not a problem, I have now moved the device a little closer to the wall, the cables that are now directly on the wall hold the plugs in place.

I have a similar situation with multiple amps running off a DAC output and I ended up going with an RCA switcher instead, which may be a safer approach.

I have a RCA switch, even a very good one, but for my taste it doesn't fit into the overall picture.

At best, I could put the Switch next to the Euforia...

 

[AnyDave]

This is not a problem, I have now moved the device a little closer to the wall, the cables that are now directly on the wall hold the plugs in place.


I have a RCA switch, even a very good one, but for my taste it doesn't fit into the overall picture.



At best, I could put the Switch next to the Euforia...

Yeah, I can understand that. I'm just worried about the stress put on the XLR jacks on the 3A.

 

[Louisiana]

I'm just worried about the stress put on the XLR jacks on the 3A.

Great, now I'm getting worried too…

 

[AnyDave]

Great, now I'm getting worried too…

Sorry, I'm just trying to help. Having a long stiff cantilever hanging off a jack like that is something I would personally avoid if at all possible. I think there might be other options that are less risky to the amplifier.

 

[Louisiana]

Everything is fine
The RCA switch has the same size as the Red, could look quite good - I order RCA cables...

 

[Honeypot]

Just pulled the trigger on ha 3a. Hope it goes well with zmf caldera.
I've got some nice 12au7 tubes. Any recommendations for power/rectifier?
Looking for deep bass and lush treable.
Thank you very much!

 

[Louisiana]

Just pulled the trigger on ha 3a. Hope it goes well with zmf caldera.

I like those combo