# BHK Preamplifier - Hours on the tubes **URL:** \ **Category:** Preamplifiers\ **Created:** [May 26, 2024, 12:03pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660 "2024-05-26T12:03:09Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![onehorsepony](https://avatars.discourse-cdn.com/v4/letter/o/b5ac83/32.png) [@onehorsepony](https://forum.psaudio.com/u/onehorsepony)\ **Post date:** [May 26, 2024, 12:03pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/1 "2024-05-26T12:03:09Z")
Hi all - I just found out from another member that the BHK preamp keeps track of the hours on the tubes. How do I find this information on the preamp? thanks in advance… ---
**Author:** ![brumtech](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/brumtech/32/27935_2.png) [@brumtech](https://forum.psaudio.com/u/brumtech)\ **Post date:** [May 26, 2024, 12:30pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/2 "2024-05-26T12:30:22Z")
If you press the black button to the left of the display for 3 seconds, you enter the Set Up Menu. You then press the black button a few times until you get to the Tube Life page which will display total hours on the current set of tubes. You can reset the hour number to zero by holding in the black button while on this page. ---
**Author:** ![onehorsepony](https://avatars.discourse-cdn.com/v4/letter/o/b5ac83/32.png) [@onehorsepony](https://forum.psaudio.com/u/onehorsepony)\ **Post date:** [May 27, 2024, 2:52pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/3 "2024-05-27T14:52:45Z")
Oh wow, thanks for that information… I’ve never even noticed that button next to the display, i always use the remote. My preamp shows that I have 1,300 hours on my tubes… How many hours before they should be replaced? ---
**Author:** ![dchang05](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/dchang05/32/294697_2.png) [@dchang05](https://forum.psaudio.com/u/dchang05)\ **Post date:** [May 27, 2024, 4:19pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/4 "2024-05-27T16:19:13Z")
If you have spared tubes give them a try, but at 1300 hours these tubes should not have fading issue. My PSAVNE and GL tubes usually sounded great until 2k to 2.5k hours. But I don’t listen to loud volume and my amps are Class D. ---
**Author:** ![onehorsepony](https://avatars.discourse-cdn.com/v4/letter/o/b5ac83/32.png) [@onehorsepony](https://forum.psaudio.com/u/onehorsepony)\ **Post date:** [May 27, 2024, 7:08pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/5 "2024-05-27T19:08:31Z")
Being input tubes on a preamp, I would think that volume isn’t an issue. So, in theory, couldn’t you determine the life of the tube more accurately on a preamp input than on an amplifier input? ---
**Author:** ![dchang05](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/dchang05/32/294697_2.png) [@dchang05](https://forum.psaudio.com/u/dchang05)\ **Post date:** [May 27, 2024, 7:55pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/6 "2024-05-27T19:55:32Z")
Both BHK pre and M1200 have the tubes at input stage, and I usually replace both around 2500 hours. But with NOS Telefunken they sound even better at 2500 hours. ---
**Author:** ![Elk](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/elk/32/1240_2.png) [@Elk](https://forum.psaudio.com/u/Elk)\ **Post date:** [May 27, 2024, 8:10pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/7 "2024-05-27T20:10:24Z")
Small input tubes can easily last 10,000 hours. While they may have aged in a fashion which is not appealing to you, I suspect something else. Is the issue rather than the tubes. ---
**Author:** ![dchang05](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/dchang05/32/294697_2.png) [@dchang05](https://forum.psaudio.com/u/dchang05)\ **Post date:** [May 27, 2024, 8:22pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/8 "2024-05-27T20:22:51Z")
I don’t disagree that the tubes at input stage will last for a long time. In my system around 2500 hours the sound is fading a bit, and tube replacement will bring the magic back. The exception is with NOS Telefunken, even at 5000 hours the sound is still great. ---
**Author:** ![adifferentpaul](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/adifferentpaul/32/282181_2.png) [@adifferentpaul](https://forum.psaudio.com/u/adifferentpaul)\ **Post date:** [May 27, 2024, 11:04pm UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/9 "2024-05-27T23:04:30Z")
I would replace the tubes in the preamp. There should be magic in the system. Replacing tubes should result in magic. Just make sure the preamp has been off and unplugged for a while before messing with tube replacement. ---
**Author:** ![Audioholic](https://avatars.discourse-cdn.com/v4/letter/a/f14d63/32.png) [@Audioholic](https://forum.psaudio.com/u/Audioholic)\ **Post date:** [May 28, 2024, 12:36am UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/10 "2024-05-28T00:36:07Z")
Although I’m sure the small input tubes will “last” thousands of hours, some of the magic starts disappearing long before that. I usually replace the BHK pre and 250 tubes at around 1000 hrs, and the system sounds reinvigorated again. ---
**Author:** ![Elk](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/elk/32/1240_2.png) [@Elk](https://forum.psaudio.com/u/Elk)\ **Post date:** [May 28, 2024, 2:59am UTC](https://forum.psaudio.com/t/bhk-preamplifier-hours-on-the-tubes/37660/11 "2024-05-28T02:59:42Z")
See, e.g., [Tube Basics and Frequently Asked Questions – Upscale Audio](https://upscaleaudio.com/pages/tube-basics-and-frequently-asked-questions) Of course, YMMV.