Rocket and Rectifiers

[David Root]

That link didn't work for me but NOS Mullard GZ34s are ~$150 these days, and the older large base ones over $200.

Quality of materials I think has a significant effect on tone, even in rectifier tubes. The older the tube, generally the better the quality of the materials, by which I mean the chemistry/metallurgy of filaments, cathodes and grids and screens.

In those days there were these tube material guru engineers/chemists/metallurgists that the best companies would compete to have the best of these guys working for them. This was definitely the case in Europe, not sure about in the US, so I think that explains a lot of why, for example, a '66, '67 and '70 Amperex 12AX7 from the same (Heerlen) factory all tend to have slight tonal differences. Mullards I'm sure do the same, and there's no doubt that a Blackburn Mullard 12AX7 and a Mitcham Mullard 12AX7 sound different, it's reflected in the NOS price.

Allegedly these gurus would act like contract workers and go to the highest bidder once they had proved themselves to the manufacturers.

The quality of the manufacturing process back then was better too. This is particularly important in filament, cathode, grid and screen functioning and life.

[rp]

Allegedly these gurus would act like contract workers and go to the highest bidder once they had proved themselves to the manufacturers.

Kind of like the Masonic Master Builders of the cathedrals.

I just read through this post. One thing about KF, most his documented quotes are from a time and place - 1980-1995, and most from Pittman's book & Vintage Guitar Magazine. The world was different then, the new ex commie tubes showing up pretty much all sucked, not just sounded a bit not as good, but just plain sucked across the board: looked wrong, sounded wrong, wrong voltages, and unreliable. From '80s to through '90s there was no reissue 5AR4 any right thinking person would stick in any amp. I believe in the NOS dogma, but the new ex-commie tubes have improved much in the last decade. KF might have a different opinion today.

[amplifiednation]

Allegedly these gurus would act like contract workers and go to the highest bidder once they had proved themselves to the manufacturers.

Kind of like the Masonic Master Builders of the cathedrals.

I just read through this post. One thing about KF, most his documented quotes are from a time and place - 1980-1995, and most from Pittman's book & Vintage Guitar Magazine. The world was different then, the new ex commie tubes showing up pretty much all sucked, not just sounded a bit not as good, but just plain sucked across the board: looked wrong, sounded wrong, wrong voltages, and unreliable. From '80s to through '90s there was no reissue 5AR4 any right thinking person would stick in any amp. I believe in the NOS dogma, but the new ex-commie tubes have improved much in the last decade. KF might have a different opinion today.

Which russian tubes that are new production have you found to like?

[rp]

Which russian tubes that are new production have you found to like?

I don't think new production tubes are great, I just don't think you have to run away from them anymore.

The one good thing from the crappy tube era was that it forced me to stock up on NOS when they were still cheap and I had fewer bills. So, I personally can still avoid new production tubes. But, I put them in friends' amps and they sound good and have proven very reliable, something that just didn't happen 15 years ago. I no longer tell people that if their amp blows up it's the Chinese tubes' fault not mine. The recent 5AR4 rectifiers seem fine and they are lasting. For a long while all the repo 5AR4s were really 5y3s on current and 5AR4s on voltage, and were a good way to damage an amp.

For friends' amps or if I'm lending an amp out I'll use whatever is reasonably priced from AES - Sovtek or JJ, I don't have the patience to tone test these things. There are a few types I'm curious about, but the prices have gone up considerably. You can source ANOS and pulls off ebay for just a little more so I've been doing that lately, so far so good.

[dartanion]

A few 1N4007s are just a couple of cents

[rawnster]

A few 1N4007s are just a couple of cents

...but not nearly as sexy as nice glowing mullard!

[dave g]

A few 1N4007s are just a couple of cents

...but not nearly as sexy as nice glowing mullard!

...but sound the same if you throw a power resistor in series with them

[dartanion]

A few 1N4007s are just a couple of cents

...but not nearly as sexy as nice glowing mullard!

...but sound the same if you throw a power resistor in series with them

Exactly Dave! Yeah, Mullards are sexy and all, and I have a few, but what a waste of money even at the $60 a piece that I paid.

Hey Dave, we're practically neighbors.

[rawnster]

Exactly Dave! Yeah, Mullards are sexy and all, and I have a few, but what a waste of money even at the $60 a piece that I paid.

Hey Dave, we're practically neighbors.

Yeah, you California dudes are always right. If the extra $60 is keeping someone from buying an amp, then they're not going to hear the recto difference anyway.

[M Fowler]

I'm starting to think long and hard about forgoing tube rectifiers myself and your right diodes are cheap and a sag resistor works well.

How do you guys handle your customers, each one wants a different custom guitar or bass amp or harp amp.

I think I'm going nuts just replying to all the questions.

[Cliff Schecht]

I always prefer SS diodes for simplicity and reliability. In all of my original designs I stick with SS rectifiers, if I want sag I'll drop a series resistor after the rectifier. I've always thought the tube rectifier into a choke setup was redundant (chokes kill sag induced by tube rectifiers) except in the first b+ node before the choke. Plus the flyback voltages induced when you throw the standby switch into a choke can ruin both the tube rectifier and the choke. But at the same time, they look so cool.

I haven't tried it yet but I've been meaning to build an amp that uses the 5v rectifier tap as a bucking winding to knock down the typically high mains voltage. Yet another reason to not use a tube rectifier.

[dave g]

...but not nearly as sexy as nice glowing mullard!

...but sound the same if you throw a power resistor in series with them

Exactly Dave! Yeah, Mullards are sexy and all, and I have a few, but what a waste of money even at the $60 a piece that I paid.

Hey Dave, we're practically neighbors.

Redwood City, eh? Cool, I just got back from the Costco there...

[Zippy]

Whoa, I used to play in a band that was based in Redwood City - back in the mid-80s.

"Cornucopia" among other names - Dave Bogart on keyboards, Jose Serrano on guitar... me on saxophones and percussion.

Perhaps you never heard of us???

[dartanion]

Whoa, I used to play in a band that was based in Redwood City - back in the mid-80s.

"Cornucopia" among other names - Dave Bogart on keyboards, Jose Serrano on guitar... me on saxophones and percussion.

Perhaps you never heard of us???

I didn't move to Cali until 2002, so I wasn't here to know ya.

As far as keeping clients pleased, I will build things the way they want them so long as they know how much things cost. To me, it's asinine to spend $150+ on a rectifier tube. Since there are no good substitutes for quality NOS available, using ss diodes and a sag resistor makes a ton of sense.

[angelodp]

dartanion, can you point to a Rocket build you have done that uses the diode, resistor set-up in place of the tube please.

ange