Do different tube rectifiers effect the bass response?

[Original Burnedfingers]

Just wondering if say a 5Y3 will sound different than say a 5R4. With an identical power supply I pulled out a 5Y3 and substituted a 5R4 and picked up about 7volts. I seemed like the 5Y3 had a little better low end punch. I thought maybe the more experienced folk here could lend an opinion.

Joe

[Sch3mat1c]

5Y3 is a lower performance rectifier than 5R4 or 5U4 because it isn't made for as large a load. You'll get more voltage using a 5U4 in a 5Y3's place. Note: you may overload the rectifier winding doing this! 5Y3 has a 2A filament, whereas 5R4 and 5U4 have 3A, which also reflects their higher current capability, which brings the second point: don't use a 5Y3 in just any 5U4/5R4 circuit!

Unless a few thousand varactor diodes are involved somehow, changing the plate supply voltage will not affect the response. The different supply impedance may affect bass, but it's all more likely in your head.

Tim

[fdegrove]

Hi,

Diode Rp can affect bass response in an audible way especially in deliberately poorly designed PSs such as for guitar amps.

With a well designed PS for audio this effect should be swamped.

Cheers,

[Original Burnedfingers]

Thanks Tim and Frank for the responses.

Tim I would never swap a 5Y3 into a circuit that was designed for a 5U4/5R4 circuit. I did however swap a 5U4/5R4 into a 5Y3 circuit for a short time. I was curious as the the change in output voltage and I saw what I was looking for.

Frank

I swapped the rectifier tube in the (Joel'sLine amp project) and this is where I thought I heard the difference. Granted it may be in my head. This was just a simple RCRC power supply with hum.

Joe

[fdegrove]

Hi,

I swapped the rectifier tube in the (Joel'sLine amp project) and this is where I thought I heard the difference. Granted it may be in my head. This was just a simple RCRC power supply with hum.

Wouldn't you say that's quite ironic?

Cheers,

[arnoldc]

i believe that when a change in rectifier was made which caused a voltage to drop or raised, the difference that you hear is caused by the change in the operating point.

i could be wrong.

[316a]

Originally posted by arnoldc
i believe that when a change in rectifier was made which caused a voltage to drop or raised, the difference that you hear is caused by the change in the operating point.

i could be wrong.

Agreed . An example : I tried various EZ81's a while ago . First I tested them and all were within a few percent of each other on the AVO . The tubes were RFT , Tesla , Mullard (2 types ring / square getter) and a Brimar . Then I measured the HT in the amp , all were within 5 volts of each other , ripple at the reservoir cap was within a mV between all of them . Then the listening : all sounded the same ! I could not detect any difference at all , the only **noticable** difference being the warmup time . Some guys on the 'HKTube Audio' forum were ranting about how the Mullard square getter version was like night and day in their vintage amps with 'an octave of extension with both the bass and treble' type superlative nonsense but I could not measure or hear any difference at all . The HK groups also had a shoot-out between different rectifiers (GZ34/GZ32/GZ37 and so on) which seemed ridiculous as some types were old side contact types and required adapters , others directly heated etc , all completely different from the original rectifier ! Of course different types will sound different as Arnold suggests . Maybe I have tin ears or whatever but I can't see how these guys can hear such a drastic difference on vintage equipment , probably with cracked carbon resistors , tone controls , electrolytic HT / bypass capacitors using speakers with crossovers (I used Jordan JX92 for the testing: crossoverless) . I can understand why some brands are better than others in terms of ratings (some brands of rectifiers arc-over whilst others are fine) but all this 'night and day' stuff about brands and sonics seems rather pumped-up and snobby to me . But who cares the square getter types always sell for more

316a

[fdegrove]

Hi,

i believe that when a change in rectifier was made which caused a voltage to drop or raised, the difference that you hear is caused by the change in the operating point.

Sure, that is of course a major factor and you're quite right in your reasoning.

However, quite often differences can be heard even when B+ is held constant between different tube rectifiers.

Cheers,

[Sch3mat1c]

Originally posted by 316a
Some guys on the 'HKTube Audio' forum were ranting about how the Mullard square getter version was like night and day in their vintage amps with 'an octave of extension with both the bass and treble' type superlative nonsense but I could not measure or hear any difference at all.
<Snip>
Maybe I have tin ears or whatever but I can't see how these guys can hear such a drastic difference on vintage ...

Hmm... rectifiers sound the same... perhaps there is hope yet of the humble 12AU7...

Tim

[316a]

Originally posted by Sch3mat1c


Hmm... rectifiers sound the same... perhaps there is hope yet of the humble 12AU7...

Tim

Tim ,
I also conducted similar tests with 12AU7 . Different kettle of fish altogether . The only one I remotely liked was the RFT . For me there is no hope with the 12AU7 , for some it's a lifetime of tuberolling to try to find one they actually like . It's the 'chocolate sauce on everything' syndrome with this tube . If you like 'em it's up to you

316a