Tung sol 6550’s from the 60’s are very good but pricey. Very similar to kt-88’s. In new production the gold lion kt-88’s seem to get a lot of favor. Not a crazy price either.
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What is the difference if any in these kt88? These are my 2 main suppliers of tubes
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Gold Lion are good for price/performance. If you can/want spend more NOS tubes would be better performing.
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To my eyes same tubes. One seller includes VAT in displayed price and the other does not (but ending price is the same).
Love it with the Auteur.
Is your 8ohm tap silent though btw?
Not completely silent with hd600 but not bothersome like 32ohm and 300ohm are.
@Essentials Lots of thoughts here.
Investing in a true power conditioner is the best move but they are expensive and large, so kind of a pain in that regard. My setup is very minimalist as I don’t have room for a rack. What I did is much cheaper/smaller and I have been able to reject 99% of DC transformer hum and interference with:
DC Blocker + Furman Linear power strip (sorry don’t know a UK equivalent) = ~$250 total
Also, I personally love the 6L6GCs and do not find them noisy compared to KT88s, so YMMV.
What does make a big difference is replacing the stock input / rectifier tubes.
I highly recommend a cheap but high quality RCA 5U4GB rectifier and for the input tube, @Wes_S pointed out a very nice $100 12AT7 which lowers the gain a little bit, but really reduces the noise floor. It is still plenty of power for my ZMFs. Keep in mind for the the 12AT7 you will need a socket adapter, but those are cheap.
If you do go the KT88 route, Justin recommends “Apex Matched” JJ KT88s which are nice. KT88s run a bit hotter though (it will make your amp and room hot!) and have more gain so I personally think there is more noise depending on the chain.
https://www.tubesandmore.com/products/vacuum-tube-kt88-jj-electronics
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Can you specify what strip you have?
Mite be available over here in the uk
Is it this one?
Says its a power conditioner as-well. Is that correct?
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I have the PST8D which is just a little bit nicer because it has two power banks to prevent noise from one bank to effect the other and vice versa. But they both offer the same excellent surge protect and linear EMI/RFI filtering. Be careful though… the photo in that link looks like US style outlets and the watermark is BHPhoto which is the New York company where I got my power strip.
Also, I would say the most prudent approach is to troubleshoot in stages just to save yourself money as you go.
First, I would replace the rectifier and get a lower gain input tube like the 12AT7 or 12AU7. Doing this greatly improved my listening experience and is just a fun way to explore different tube sounds.
Second, get the Furman surge protector and conditioner (assuming there is a UK version), at a minimum this will help protect the tube amp.
Third, get the DC blocker and/or a nicer power cord.
Curious what others think, but these are my 2p.
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@Essentials , I’m hoping that @SebastienChiu can join this conversation.
Sebastian works for iFi, whose products should be readily available in the UK. And since you were looking into getting a DC Blocker anyway, hopefully he can help you come up with a step-by-step roadmap to getting rid of your amp noise.
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The Furman products I’ve been able to evaluate have consistently been cheap, underbuilt, over marketed junk.
There are many examples and pictures in the power conditioning thread here.
An IsoBar 8 would be far better imo.
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Where were you when I bought my Furman?! Just kidding 
Sorry you had a bad experience with Furman… I was going off this Wirecutter review where my unit in particular turned a 5000v surge into 40v. So I wonder if they have stepped up the build quality since the model of the power strip that you tore down. But as it turns out, their top pick is a Tripp lite which is the same brand as the IsoBar 8 that you are recommending.
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@gugges It looks like the the Tripp Lite is a surge protector, and not a power conditioner (unlike your Furman 
), and therefore doesn’t help (or hinder) the noise problem.
@Essentials As Torq explained in the power conditioner thread, the benefits of a power conditioner are debatable, and the only way you’ll find out if it works for you is to try it. I have the PS Audio Power Plant 3, which helps a lot, given that my tube amps (A&S Nautilus and Pendant) are on the same circuit as my freezer, but it’s a lot of money. I’m assuming that my power cables help too, since they were designed to reduce noise.
Here are some options that are available in the UK, if the iFi DC Blocker doesn’t work:
iFi Power Station
PS Audio Dectet
PS Audio Power Plant
As mentioned, I can only speak to the PS Audio Power Plant, but a few forum members like @ValentineLuke have the iFi Power Station, which is less expensive. Perhaps you can buy one from a store with a good return policy, in case it doesn’t help.
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Certain Tripp Lite units have isolated filtered power banks.
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Yes, my mistake, I was looking at the Tripp Lite model in the Wirecutter article, not the isobar model that @ProfFalkin mentioned.
Irrespective, I’m still not sure if Tripp Lite sell 230-240V models with UK plugs.
The cheapest UK equivalent appears to be this Isotek power conditioner.
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Gotcha, all good. I’m afraid I’m not sure about UK plug models.
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I have ordered a 5AR4 to try and see if these help. Will this rectifier lower the gain?
12AU7 seems like it doesn’t fit from photos 
What am I missing?
Whats a good input tube that will lower the gain?6SN7?
Im already using AudioQuest NRG-Z3 Mains Power Cable | Future Shop
I have a ifi DC Blocker on its way and this on its way Tacima CS947 6 Way Mains Conditioner 2m | Future Shop
Thought I would buy all the cheap things first and see if any of them fix the noise.
Would you guys say there is something wrong with my power because wen I A/B test the mogwai with the cayin iha-6 with the HD600 I can’t really hear a notable difference in presentation. There sounding 99% the same to me. Ever so slightly more punch out of the mogwai…
Maybe I have bad power?
The 12AU7 would need an adapter to fit the 6SN7GT/6SL7GT socket. I’ve never used the adapter. The 6SN7GT would be the lower gain compared to the 6SL7GT.
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Thanks for the tag @PaisleyUnderground!
@Essentials - we do have quite the background in power and for the lack of a better of saying it, things that solve different kinds of questions for different problems that come as a result of power.
If budget is of no concern after trying the DC Blocker, I would definitely recommend starting with our Powerstation as it already has a lot of the external tech, like what you see in the AC iPurifier, built-in.
Let us know how the DC blocker works for you, how it affects your system, and we can continue diagnosing with the crew here from there!
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5AR4 has more power output than 5U4G (no effect on gain, which is determined by the input tube).
12AU7 and 6SN7 each have a gain factor of 20, which is lower than the aforementioned input tubes.
I don’t view the similarity as being generally affected by “bad power.” You may perceive more of a difference by trying the 8, 32, and 300 outputs. It is possible that the amp and your ears/brain require some time to settle in.
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