BHK Preamp tube rolling

“more of everything” is a good description of what my limited experience has been with 5mA and 12AU7 tubes. It may become fatiguing over time but for the moment I am enjoying 5mA with GE JG-5814WA tubes and my Aric Audio Super 300B SET. But I have almost a dozen tubes I am going to roll in and the reason I asked if a consensus opinion had developed is because I don’t want to listen to each tube twice.

As an aside, I have also found there is a difference using the RCA output from my DAC versus the XLR output of the DAC into the BHK. RCA is smoother, less detailed in the top end, and probably a bit more pleasing for female vocals. XLR has that more of everything quality. The differences are noticeable but modest. I am using Harmonic Technology Pro Silway cables with both.

Good news :+1:t2:

After how many hours do you recommend changing the tubes? I last changed 2 years ago and I just looked, over 6000 hours. It seems Ive lost a bit of gain. Is that a sign to change? No idea what is in there now. But I see 4 spare sets of tubes in my box. I will be ordering more haha. Your help is appreciated!!

Noise. If I detect an audible increase in the noise floor, I start thinking time to replace. I don’t recommend any canonical rule of thumb for hours of on-time to replacement. A good set of tubes can last a very long time indeed. It isn’t overly unusual for tubed gear to run on the same set for a decade. Be lucky enough to get tubes from a particularly good lot and you can forget about fretting over a usage counter. If they are still quiet and provide enough gain, stick with them. You’ll likely be better off since the set you replace them with may not be from a strong lot (manufacturing variation from lot to lot does matter). Grading only characterizes beginning of life, doesn’t characterize longevity.

MUCH appreciated Owlsalum! I ordered a pair of matched gold lions after reviewing the last parts of this thread. But I will hold off on doing the replacement. THANKS!

When facing the BHK Pre from the front; is the tube on the right the one for the right channel?

Yes!

Guys, if you want the best tubes for your BHK Pre, buy ECC80 Philips D getter Pinched Waist WK6 or WK4 codes. They blew out of the water every 12au7 I tested and I got all of them :slight_smile:

Tough to find NOS pairs, I have wanted to try some ECC80’s in my linestage for some time. So far, the Siemens 5814 triple micas are my personal favorite, followed by the G73R’s

The Phillips and re-brands from Phillips/Heelen have the gold pins, correct?

Best,
-JP

Yes, they have gold pins.

Hi, I’m hoping to resurrect this thread to ask a question. Has anyone done any objective (measured) testing between the gain obtained with 12AU7 versus 6922 (and variant) tubes in the BHK Preamp? I realise that 12AU7 and 6922 tubes have different quoted gains but I also realise that the BHK has different voltage and current switches with (might) affect the overall gain in the system once they’ve been adjusted. Also, given that the unit is a hybrid Mosfet / tube unit, the differences may be negligible.
I have lots of Telefunken 6DJ8’s and really love them but I’m also looking at some 12AU7 variants to role. I don’t have the original OEM tubes to test so I’m hoping that someone might have some insight into the gain. I am struggling to drive my Pass Labs XA25 as it has quite a low gain as well. Don’t want to get some 12AU7’s and lose even more gain!
Really loving my BHK Preamp. When I first got it, I said it was a keeper. That was 5 years ago and I have no intention of ever selling it :wink:
Mark

Has anyone compared the Apps 12au7’s to the PSVANE Horizon Series tubes?

Reading through reviews on Amazon and they seem to better the more expensive Art series PSVANE tubes,. Many even thought they sound better than some NOS tubes.

My Apos tubes have a noisy tube in one channel so I put in a pair of Gold Lions. Not a bad sounding tube for the money, but they don’t compare to the Apos tubes, but at least the noise from the one channel is gone now.

I also have a noisy Apos tube. The only moment to notice this is when switching the Pre on and off when the power amp is also powered up.
Their sound is still wonderful though. I didn’t try yet if cleaning the pins would make a difference.

First Apos set I received was faulty and was replaced. That makes me think their QC could be improved…

I went from stock tubes to Gold Lion with better results. Then I went to Brimar and ever since, I have no desire to change and have a back up pair.

Are these a direct replacement for 12au7’s?

Any recommendations on where to purchase?

Yes 12au7/cv4003, Upscale Audio. Kevin’s stash, no Cryo.

I have the Apos Ray Select 12AU7 in my BHK preamp. I think they are excellent. Much preferred over the Art tubes (which are good).

The Apos tubes provide more low end weight and broader soundstage in my system. Very happy with them. I find the Art tubes to have a softer quality.

I contacted Apos and even though the Apos tubes I bought were used, they replaced them for me for free, due to one of the tubes being noisy. I’d say that’s excellent customer service.

The new tubes sound amazing. They definitely elevate the performance of the BHK pre.

Impressive.