Just save yourself a bunch of time and grief by contacting Andy Bowman at Vintage Tube Service to get specific guidance. I only deal with Andy on my tube purchases and he knows what he is doing at a fair price.
Preamp Rectifier Tube Confusion
I have a Primaluna Prologue 3 which uses 5AR4 rectifier tubes which id like to roll. I’m looking at ShuGuang WE274B tubes which list as replacements for 5AR4 / 5U4G / 274B.
However, the Primaluna manual lists compatible tubes as: GZ34, CV1377, 5V4G, 5T4, 5Y3 and Upscale Audio also list the Philips 5R4GYS.
Any idea if the ShuGuang would work?
However, the Primaluna manual lists compatible tubes as: GZ34, CV1377, 5V4G, 5T4, 5Y3 and Upscale Audio also list the Philips 5R4GYS.
Any idea if the ShuGuang would work?
28 responses Add your response
@jjss49 I have my 3 favorite recording’s that are superb at demonstrating vocals, soundstage and separation. They also do the magic act and make the KEF Q150’s disappear...if I can’t hear a difference then I’ll chalk up the 5R4GYS to pure aesthetics. 🤷🏼♂️ norah jones: little room roger waters: what God wants chris jones: when your gone |
Philips 5R4GYS in the house! Beautiful glass...haven’t had time to give them a critical listen. https://freeimage.host/i/2oG08B |
If this indeed due to a voltage increase or decrease, so be it, but it did and does change the sound.I'm sure it does! But that is the only reason they make a difference- and if its all about getting the best sound, you can do better than that by going solid state (and making sure that the circuit and power transformer are happy with the increased current draw) as long as the rectifier/transformer combo doesn't make noise- if it does, there are way of shutting it up. Every time you think you've surpassed the penultimate, it turns out not to be the case- there's *always* a next step. |
Ralph...
I think the world of you and have learned very much from you over the years.
I just posted what was written in the review. However, I have sold, (as a dealer) and owned, (personally), quite a few preamps that have had tube rectified power supplies. I have found without question, that I could change the sound by replacing the tube rectifier. If this indeed due to a voltage increase or decrease, so be it, but it did and does change the sound. |
"To my mind, the 5AR4 tube rectifiers were at least partly responsible for the preamp’s tonal integrity, fleshing out the lower octaves and, in particular, infusing upright bass and cello with a full complement of tonal heft."That's a bit of a sketchy claim. Its far more likely that the audio circuit itself is responsible for this. A tube preamp can easily do exactly the same thing with solid state rectifiers (for example, by using 6SN7s in the line stage). Seriously, solid state rectifiers are now good enough that they easily keep up with tube rectifiers in terms of noise, but they don't have the voltage drop (which varies with current draw) that tube rectifiers do. Its for this latter reason that tube rectifiers are preferred in tube guitar amps, since that can impart that 'blues' sound which is really the sound of an amp that has a sagging power supply. If you were to measure the voltage drop across the rectifier, you would find that the best sounding ones for hifi are also the ones that have the lowest voltage drop. There's nothing magical here- they respond to physics just like everything else in audio. And again- the power supply has to be working properly in that the filter caps are good and sufficient to properly bypass the supply and prevent noise from getting into the audio circuit. It that bit is true, then the only way a tube rectifier can affect the sound is by the voltage it puts out. So it should follow that if you use modern solid state rectifiers, you can make it even better, and in practice that turns out to be true as well. |
This is a quote from a recent review in TAS on the PrimaLuna EVO400 Preamp: "To my mind, the 5AR4 tube rectifiers were at least partly responsible for the preamp’s tonal integrity, fleshing out the lower octaves and, in particular, infusing upright bass and cello with a full complement of tonal heft." +1 |
Ima sucker for aesthetics...the WE274B is sexy piece of glass!The two tubes have the same pin base with similar voltage limits and current specs, so you can interchange them and see how it goes. What is less obvious is the voltage drop you will see between the two- since the specs are very similar I suspect there will be only a minor difference between them. You could also use a 5U4 which has the same pin base, but 5U4s have a greater voltage drop, and the 5AR4 was designed to have a controlled warmup time so as to allow the audio tubes (in particular, power tubes) time to warm up to prevent a phenomena called 'cathode stripping' which really does not occur with signal tubes as seen in a preamp circuit. The 5U4 warms up almost instantly. I've no experience with the WE tube. I'm saying that if looks are important, the ST-7 envelope used by the WE tube is also used by the 5U4. But I suspect you will find the 5U4 to sound a bit 'sleepy' due to the higher voltage drop across it, but they are so cheap you might get a pair and see what you think. |
@jl1ny not to be a killjoy in your case - but if you are going to tube roll to better the sound of the your system, do it with input tubes - spending $ to roll rectifiers are barking up the wrong tree https://www.primaluna-usa.com/tube-rolling |
@jl1ny
However, the Primaluna manual lists compatible tubes as: GZ34, CV1377, 5V4G, 5T4, 5Y3 and Upscale Audio also list the Philips 5R4GYS.My bad, I see now you are saying that the manual lists the above tubes as compatible IN ADDITION to the 5AR4. I had read somewhere before what atmapshere is saying, that different but properly working rectifier tubes should not change the tone of a preamp, and I also believe the same for an amp, such as my Dynaco ST-70. When I purchased my Mullard 5AR4 a number of years ago, they were reasonably priced, and they last forever and a day. Its one and done. |
+1, on the Mullard (Blackburn plant) being the most reliable and longest lasting, GZ34/5AR4. You should most definitely contact Kevin Deal, at Upscale Audio, regarding whether a rectifier change will make an audible improvement, in your Primaluna gear. He has much experience with the brand. https://upscaleaudio.com/pages/contact-us |
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If the 5AR4 changes the sound of the preamp (assuming the originals are good) then you have bigger fish to fry. It should not make any difference at all- the difference between good 5AR4 and lessor examples is reliability. The power supply has to be designed well enough that the audio circuit is properly bypassed and the sawtooth waveform at the output of the rectifier is filtered out. If that has been done, then its expectation bias if you think you hear a difference. OTOH, you will hear a difference from the tubes in the audio path- if you want to hear a nice improvement that's a far better place to put your dollars! |
be careful applying these ’review results’ of rectifiers in little headphone amps to real amps driving real speakers with serious electrical loads as pointed out below, think about what a rectifier actually does in circuit ’after enough scotch, malt whiskey and/or 420, even the same sh*t will sound different’ LOL |
Here's an excellent, (although quite long) thread on just these tubes: https://www.head-fi.org/threads/dubstep-girls-massive-5ar4-5r4-5u4g-rectifier-review-comparison-rect... |
it should work but just in case, i would write or call primaluna and ask to be sure - they are in california, are usually quite responsive that way if something goes wrong when u use the tube they will more likely honor a warranty repair unsolicited rectifier tube advice -- for PL the buck stops at the Mullard or Amperex old stock 5AR4 GZ34 -- it is the best, period |
