Can YOU hear the difference in Tube Rectifiers?

[NOSValves]

Oh wait how will I get the puddle of mud past the wife hmmmmmmmm

 

[stormytaylor]

Every once in a while this nasty topic of tube rectifiers vers SS rectifiers vers different types of tube rectifiers pops its ugly head up yet again. Its similar to the capacitors due sound different threads on all the forums.

Years ago I graphed the voltage differences between different 5AR4's to arrive at the operating B+ voltages in the Dynaco Stereo 70 amplifier. What I arrived at was the differences in voltages did made very small listening differences. Years ago I started using the so called diode mod in my Quicksilvers and this spread to Dynaco's. Using the diodes in conjunction with tube rectifiers does both change the sonics and the life of the tube rectifier. In the Quicksilvers it prolonged the life of the weakest part of the amplifier the dual 5AR4's. Still have not gone thru a pair of them and its been 13 years since I posted my mod.

Since it has been proven that some can detect differences in capacitors it is also possible that some have the ability to detect differences in tube rectifiers and solid state rectifiers in my opinion. I formed the opinion that diodes in conjunction with GE
5U4's gave me the sound that I found most pleasing in the Dynaco Stereo 70. Note that this is after re-adjusting the individual tube bias and my modified stereo 70's.

Now, I carried my research to my home made point to point Aikido 6SN&/6SN7 line stage. I started with a standard 5Y3GT rectifier and graphed the voltage changes using various 5Y3's, 5AR4's, 5U4's and a number 80 with a adapter and finally a mercury #83 tube using my home made base adapter.

I found the most pleasing in my line stage was a Japanese Mullard followed by the #80 followed by the #83 mercury rectifier. I followed up with trying the top two rectifiers on my list with people that I had listen to my stereo setup. I simply played the same passage on a CD and asked if they heard any differences and 97% favored the #83 mercury rectifier.

This to me seems to be enough to tell me that some can hear differences between rectifiers and that transfers to slight differences in the material that is being played.

 

[Wharfcreek]

StormyT, I think you're on the right track with your research. However, I have to ask if you tested each rectifier tube prior to testing the results of that tube in the amp? Here's my belief; and it basically goes to the prior statement that amps DO NOT KNOW where they get their electrons from: Amps only know how many electrons they get.....and how fast they can get them!

So, to me, this is not necessarily about a 'brand'......it's about 'type' (as in the given 'specs' on a given unit.... AND.... if the individual rectifier itself is up to it's stated performance level. As Gadget somewhat make the point; a half dead rectifier can sound really crappy! What he admitted he did NOT do was to verify that, in fact, the rectifier was truly half dead! I think there's been some missing data in the past in that all these rectifiers being used in all these sound tests are, in fact, operating properly. The thing I've yet to see in ANY of these reported 'sound tests' is the results of the rectifier tests as an individual component. Not that it really matters, but I recent ran a number of my older tube rectifiers across my Hickok and I was really rather shocked at the results. Some of my "Good" rectifiers....as determined by being Mullards, GE, Amperex, or other 'brand-preferred' types....really were NOT all that good.....at least as far as the tube tester would indicated. SO....... if being used in some kind of rectifier shoot-out..... I believe this fact alone would skew the results to the unacceptable level....without ever really knowing it UNLESS the tube testing had been done. But, going back to the issue; If four GZ34s are all pitted against each other in the same amp with everything remaining the same EXCEPT the substitution of the rectifiers...... I would believe that if all four GZ34 had the same 'test' specs, then NO ONE would 'hear' a difference in any of them. On the other hand, if the results of tube testing revealed some difference in either voltage or current delivery, then perhaps 'yes'.....an audible difference might be noticed, particularly if the test were done at the limits where the tube differences would show up, like in louder volume levels.

Anyway...... MARK!!!...... I think you have a really great approach to your builds, and I envy your knowledge of PS construction. So much so in fact that I plan to lean on you for my next build....which I hope to begin some time this fall. Nothing too dramatic.....but I have some old iron around here and I'd like to do a pair of mono-blocks....either from an old pair of Scott amps, or from some old Sherwood; with the former being 6L6 based and the latter being EL84 PPP.

Anyway....... CRAIG...... If you start selling dishwashers with internal 117 VAC outlets......or Stand UP bath tubs....and use my 'controversial thread' as a soap box, I wet-noodle lash you until you say 'uncle'.........lol.

All good commentary here......and while the subject may have been covered many times previously...some of the comments here are really VERY educational, and I hope will do more than just me some good! WC

 

[Pio1980]

I think tube rectifiers in power amps vary in their current limiting, introducing varying degrees of power stability to the amp. Solid state rectification should always be more rigid, depending on the demands vs the inherent current limiting of the power transformer and the rest of the supply circuit.

Sent from my SM-N900V using Tapatalk

 

[buglegirl]

I think tube rectifiers in power amps vary in their current limiting, introducing varying degrees of power stability to the amp. Solid state rectification should always be more rigid, depending on the demands vs the inherent current limiting of the power transformer and the rest of the supply circuit.

Without getting argumentative that statement could be taken in the inverse.

Varying degrees of Instability can be introduced into the circuit using tube rectification.

Now that being said and to stay fair. I do think that tube rectification has its place in the chain. And that some tube rectifiers could produce differences within the circuit as to affect sound.

But as I am sure a few people have stated. If a power supply is designed and executed properly no matter what the components it should just stay out of the way IMHO.

Frannie

 

[buglegirl]

Yep. Build it for (X + 5) and don't ask for more than (X). So if it's tube or SS, it won't matter. Then you could throw in a weak rectifier that provides (X+0) and you'd never hear the difference. But too many folks who post their listening experiences must run their amps at max power when they do it because that is where the marginal performance is going to show itself with (A vs. A) tube swaps.

I have a collection of 20 NOS 6DZ7's that I've profiled in an amp providing 300v with a 218R cathode resistor. The cathode voltages range from 11.45v to 13.2v with a fairly even sample of voltages in between. All burned-in until stable. 3 of them run at 12.0v and are of 3 different brands. There is no doubt in my mind that if 3 random posters to this board were to paticipate in a test of swaps on those tubes there would be preferences for different brands. Those tubes are all made by GE.

Good points ... I will throw into the mix that Tube Rectified gear many times is running right at the ragged edge vs Solid State which is typically easily over built.

Just saying that tube rectification tends to lend itself to wider ranges of performance. And in turn some of that difference trickles into the one tube vs another sounding different debate.

Not trying to open up the can of SS vs Tube worms mind you as Tom already opened up enough of a can of worms with this thread.

Not that people don't make the same claims about SS diodes. They certainly do.

Frannie

 

[gadget73]

Tube rectifiers also tended to work into minimal capacitence, just due to the age when they were made. I try and up that somewhat, but you can only go so far with physical constraints and limitations of the tube itself. No giant first capacitor for those rigs.

 

[Thatch_Ear]

I sat in on a rectifier rolling session one afternoon. I want to state that the system was really high dollar. Everything was about as good as it can get. Everything was custom or customized and the sound was about as accurate as you could get. We used a single source and a single tune and rolled at least 20 different rectifiers.
Yes there are different voltage drops. However we rolled at least 2 different brands of any one type, often 4 or more.
It has been a while and I can't remember every rectifier. All were well used tubes, none used for the 1st time, but the amount of hours differed greatly.
Cutting to the chase the number one, and no doubt was the Mullard 5AR4. We listened to 4 or 5 different 5AR4s and the Mullard was the only one to come in close to the top.
The second best was an RCA JAN 5V4, old and lots of hours. All the 5V4s showed well, this was the best.
A couple of 5U4s were very good, but I can't remember what brand. They were old US tubes though.
All of the better tubes were rolled in at least 3 times against others of the same type. We did it as well as we could, with the last rolls being blind to type and brand.
More than just diodes, and years ago a member named Mike posted a lot of very good results on rolling rectifiers. Buried deep in the archives, they are well worth the read. He was very fond of 5U4s if I remember correctly. This was from when I was the mod of the Tube Forum (only the one in those days) around a decade ago.
Thatch

 

[GYMusic]

If anyone out there can hear the difference between different "healthy" rectifier tubes... or for that matter, audio output tubes, I will hire you as an assistant recording engineer with full medical benefits, moving expenses and a competitive salary.*

*After 100% successful completion of rigorous audio tests.

 

[Kegger]

Had many a shootout with different rectifiers, even producing same voltages. (with others present)

CAN hear a difference, generally easier to hear in less parts count designs, like preamp or single ended.