New amp arrives today!!!

heiney9

Atleast 12AU7's are relatively cheap compared to 12AX7's. If you need any rolling advice I've tried or are about to try about 90% of them.....lol. I am about done buying so if you do Ebay we won't be bidding against each other.

H9

nspindel

I'm going to avoid the temptation to go crazy with tubes all at once. I want to go one step at a time and appreciate the impact that each change has. The rectifier was an easy place to start, there's only one of them! But the 12au7's are next!

heiney9

50's Valvo Hamburg long plates (there are 4 or 5 types) I managed to have acquire all of them.
50's Brimar CV491 long black plate, square getter
50's early 60's Brimar ECC82 long gray plates, sq getter then round getter
50's CBS JHY 5814 black plates
60's Raytheon CK 5814 (3) hole gray plate windmill getter
late 40's thru 1950 Tung Sol 12AU7 black glass, black plate. They make a 1948 clear glass, black plate with a vertical "D" getter that is fantastic. I was able to find a single but have never seen another. They are ultra, ultra rare.

I like the Heerlen Holland tubes also, but it's rare to find a deal (they are pricey) and frankly the early long plate "D" getter Valvo Hamburg's are equal to or better tube and cheaper.

The sleeper in the group are any of the long plate Brimars. Not many made it over here so many times you buy oversea's, but they can be very economically priced and they rival the best. They have Mullard like qualities, but a little less bloat and bloom in the midrange and the highs don't fall off, but they still have that sense of space.

Those are among my faves.

Happy rolling

H9

P.s. another ultra rare tube is a Telefunken labeled 1956 Siemens ECC82 long plate, slanted "D" getter w/foil. This tube is superb. Talk about a sense of space and bringing the recording right into the room....holy cow! Again I only have a single and I have seen a few FS (that I was able to verify) but the price was ridiculous on Ebay.

Brent Jesse has them: see excerpt below


12AU7/ECC82 Siemens made long plate type, Siemens factory code, VERY RARE!

New Old Stock in white box, labeled for Telefunken. This tube is fast becoming extinct! Seldom seen 12AU7 Siemens made longplates, a rare find! A fantastic, long-lived tube with unequalled sound quality.

$200.00/ea.

in stock

P.s.s I can get away with a single tube in the Mini Max since each tube performs a different function they don't need to be the same. In fact it's encouraged to use two different tubes.

nspindel

My amp has a driver triode and a line triode for each channel, and can operate in triode or ultralinear mode. It's recommended that the driver triodes be matched and the line triodes be matched, but no need for the two pairs to match.

heiney9

Everyone wants tight matching tubes, for power I can see an advantage. But IMO, up to a 20% match is pretty much inaudible on signal tubes. I am very anal about my system so I don't take anything lightly. But I've never subscribed to paying a lot extra for matching signal tubes. I know some don't (won't) agree with me on that.

In the end we want everything to sound as good as it can and buying new, matched tubes from a dealer at 5-10 times the price when you can find used ones for much less floats some peoples boat.

In my tube travels (for me personally) I never have been too discerning about tight matching and it hasn't seemed to diminish my enjoyment one bit. They need to be close, but if one pair is a 5% match and another pair is a 15% and the latter is 1/2 the cost......I'm going with the latter.

But then again the EE MM doesn't need matching pairs to do it's thing and the only other place I use tube pairs is the office rig and I really don't hold that rig to the same standards as the main rig. So maybe I'm a bit more laxed in that area.

Also the "vintage" tubes of yesteryear were works of art and many were built to exquisite standards, especially military contract tubes, so for me only using "vintage" tubes it's not an issue because out of the gate they were excellent.

Current stock tubes, I would certainly pay close attention to matching, etc as the build quality and materials is lacking comparatively.

H9

P.s. and you certainly don't want to match a weak tube with a strong tube. Also, I don't think any of my "vintage" tube pairs has a greater mismatch than about 10-15%.

nspindel

nspindel

Ok, the bass just showed up to the party. This is always cliche when talking about tube rolling, but a layer of grunge is definitely gone. Much more stability and authority behind bass passages especially at higher volumes. There was some bloat to the bass response before that is now tight and controlled. Not sure I'll bother with a whole lot of back and forth switching between the Mullard vs. the stock Sovtek. Not really much of a contest. And an hour ago I thought the Sovtek sounded great....

nspindel

One thing cool about making this amp sound better is that I'm also playing a "How good can I make a pair of Monitor 5B's that I bought for $60 sound?" game. I love the old monitors!

heiney9

Yeah, there isn't a better sounding or longer lasting GZ34 (5AR4) out there. It makes a huge difference, doesn't it?

My 5B's sound superb with my 6L6 amp. I am always smiling with this simple little rig. Granted it's in a bedroom and somewhat nearfield. The bass they put out is impressive. I can rattle the dresser drawer pulls and a sliding closet door track without much volume.

Pretty cool

Enjoy

H9

nspindel

And it's a killer headphone amp. This thing is just awesome. I have zero ability to get my SDA's going in this apartment, just no space to make it work. But I may pull them out of the closet and fire them up just to hear how they sound with this amp.

juanvperez

Hi. New member here. I've been following the discussion on the VPI 299d because I own one too and I really like it. My question is with the tubes. I've also replaced the stock rectifier tube with a NOS Mullard and it made a very noticeable difference. I was surprised by that. Now I want to swap out the 12AU7 tubes. Do you know exactly which ones are the driver tubes and which are the line tubes? I want to try the driver ones first since they are said to make the most difference, but I'm not sure which ones they are in the amp. Are the ones in the middle or the ones on the outsides? Any guidance you could provide would be appreciated.

Thank you!

nspindel

Hi @juanvperez, sorry I never saw your reply here. I knew the answer to that question at one point, Steve Leung told me himself. I'll give him a call and get the answer.

nspindel

@juanvperez I spoke to Steve, he confirmed that the inner two triodes are the input tubes and the outer two are the drivers.