45 tubes for Yamamoto A-08s

I am new to this type of tubes, i said to myself never buy tube amp anymore, but it was hard to resist when Yamamoto A-08s (from my old wantlist) turned up for sale at affordable price, finally. And i bought it (no more cartridges this month for sure, i am saving on new tubes). 

So many amazing reviews online, especially from people who use same speakers like my Zu Audio Druid.

Damn, why do i need another amp if i already have First Watt praised as much as the Yammy with same type of speakers. Maybe for my final comparison of the best Solid State vs. SET ... who knows.

Anyway, my unit comes with used tubes supplied originally (NOS) by the manufacturer.

I know nothing about 45 tubes and i wish to learn quickly.

The most popular NEW replacement is Emission Lab 45s ($648 for a pair in USA now, the price will be higher soon).

Maybe there are some cheaper NOS tubes available ?

Please recommend me something, especially if you have same Yamamoto A-08s amp


I owned that amplifier along with the Jeff Korneff 45 when I owned my horns. I tried the EML solid plates in both amplifiers and thought they gave a much more HIFI rendition. Dynamics and bass were good but just not my cup of tea for a 45 and the Yamamoto A08 is a lit up sounding 45 amplifier anyway. 
I would stick with the NOS and found the order of priority for the best in my tastes as follows:
National Union
All of the above were NOS shoulder tubes. I would only purchase them from a reputable seller of tubes. On EBAY there is a chance of good tubes but you would have to make sure of return privilege and stellar feedback on tested tubes with previous sales.
Clearly a pair of RCA Globes with the flying saucer getter is to die for if you like the sweetness of the 45 however those are old and hard to find with potential high failure rate but a beautiful sound with a somewhat rolled off top end.
All is this is based on my system and to my tastes at the time so it all depends on what your after in the end and your speakers etc. It should be a clue the manufacturer included NOS with the amplifier.
I have some NOS I might consider selling if you ping me I can explain further.


I also have some left over from the previous amp (WLM Minueta), very rare military Telefunken E84L matched quad and ECC801s matched pair ... all in original boxes, purchased from The Tube Museum NYC long time ago. Some rare gold pins NOS Sylvania AT12WA Gold Brand quad and Japanese Matsushita ... since i don’t have an amp for those tubes i am willing to trade (if anyone interested).

Or maybe i should make a preamp with them ? 

@jmolsberg Thanks for the link. Spent the afternoon reading all Kevin's notes.
I have literally sold hundreds of pairs of old stock 45s and agree, for the most part, with gwalts ratings. I prefer a more linear sound so I think Tung-Sol are best, although most of my clients prefer National Unions. I dont think that there is a bad old stock 45, but universally National Union, Tung-Sol and RCA are considered the best ST shaped  tubes. I gave up on the globes due to gas, leakage and the fact that they never seemed to travel very well. So my experience with globes mirrors that of gwalt. Contact me directly if I can be of further help. I keep a relatively low profile but have been doing this for over 20 years.
Searched the web a little bit and found some interesting topics:


Pricelist for Emission LABS tubes and stuff in Europe
Congrats on a beautiful amp. 6moons has a good write-up on the Yamamoto. The consensus is that the EML tubes push an already pretty hot amp into the lit up category.
@noromance thanks

EML for $500 extra compared to vintage NOS , big difference for a pair of tubes
Ok, it’s me again
Waiting for my National Union 45s i start thinking about RECTIFIER 80 tube too, i need only one. I have zero experience with this type of tube.

Any recommendations?

On ebay i see many of them (NOS) from the 30’s and 40’s:

Sylvania 80
Silvertone 80
Cunningham 80
National Union 80
Radiotron 80
Telefunken 1064

For some of those European tubes the sockets must be modified like this.

I have standard 4 pin sockets.

I am like this dude 
No, they do mods only for those who’s buyin’ an amp from them.
I got my amp from Japan, i want to use what i have without any mods in the tube sockets.

So i’m looking for RECTIFIER tubes that i can just plug and use.

P.S. And new EML RECTIFIER tubes are too expensive, over $300 for a single tube that’s crazy!
I decided to try Australian made Radiotron 80 (NOS/NIB) first. Damn, it's from the 40's, definitely the oldest piece of gear in my system. 

The next step is 717A preamp tubes, something like this ?
Westen Electic is what i have now in the amp selected by Yamamoto-San, but i need NOS for backup
To my surprise i have plenty of gain with my passive Pass ALEPH L preamp with Yamamoto A-08s, this combination with Zu Audio Druid is shockingly good.

I was a little bit afraid that with 2w single ended i will need some active gain stage, but i was wrong! No need for any active gain stage in this combo (even in my big room). If someone thinking about active gain stage with this amp i must say with 101db speakers and some nice phono stage the active gain stage is a waste of money for nothing. Only passive preamp! I love Pass Aleph L because there are 4 inputs and 2 line outputs. 

Still listening with the stock vintage NOS tubes provided by the manufacturer.

But luckily got my NU 45s (from USA) and Rectifier 80 (from Australia) back up before covid-19 situation.

I have experience with passive line stages. Basically it’s just a volume control. My first was using the digital volume control in my dac back in the 90’s. I’ve also used extensively resistor and transformer based. Including  two from Bent audio and a Placette.  Most SET amps are easy to drive and work fine this way. Some push pull, but not usually as easy. 

I wouldn’t agree that an active preamp is a waste of money. For the price  a passive is a good choice. But in my much experience a quality active preamp will give much more performance than a passive. My experience was comparing to my Atma-sphere Mp1 years ago. Many times more costly too. There’s more to an active preamp than gain. Usually your source  is putting out more gain than you need. If your listening just for detail and lack of distortion,  a passive is hard to beat though. 

@sdrsdrsdr yes, my concern was only about this particular combo, the reason i asked before for Yamamoto preamp than nobody tried, i realized that it will be overkill for my 101db speakers. 

Pass ALEPH L preamp available in several versions, the one i have is passive when the volume control in under 3 o'lock, then it will be an active pre if the volume is more than 3 o'clock. Clever design from Nelson Pass. With my speakers and this Yamamoto A-08s (2w) i don't need an active gain for sure, hard to believe, the volume control on my pre is under 12 o'clock (and this is god damn loud). 

Yes. Like I said. Your source is more than enough gain for your Yamamoto to be driven. Probably would  be too much wide open. I used to have one of those myself, the Yamamoto, years ago. Along with a 300b and 845 amp that I used when I had  my Avantgarde Trios. They are excellent. I still own a 45 amp that I use when I put my Lamhorn speakers in my system. It’s an Oliver Sayes build that is based on the Korneff design.
Since I sold some of the rarest 12at7wa tubes from my ex push-pull amp., I’m thinking about much older 45 tubes from the 1930’s for my Yamamoto A-08s. ST bottle shape or Globes, Solid Plates or Mesh Plates... This is where you lost me... Vintage tubes are addictive, you’d better get rid of them all, or you’re always buying some more. I thought I’m done with the tubes, but I’m still buying more. Stop me somebody ...

After some research these trio is on my radar now:

-RCA 80 GLOBE tube (tested 56/52 where min is 40)
-RCA 245 GLOBES (PAIR) (tested both 66/66 where min is 47)

Any comments?

I don’t have a tube tester, but I hope I can trust a seller who’s got calibrated TV7 tester and life long experience.
Tube testing is another quest, I know nothing about it. Would you buy a tube with tested results stated above?

This is what I received so far from another tube dealer: NOS 717A matched pair (mushrooms).

National Union 45s from another audiogon member.

And this Radiotron 80 from Australia

RCA Radiotron UX-245 was amazing!

Unfortunately one tube died slowly glowing purple and making heartbeat sound in my woofer, never seen anything like that before with old tubes, but those Balloons are by far the oldest I ever tried (from 1930’s).

Seller shipped replacement tube, but that one also died same way. So the Globe 45s goes back to America for refund.

Rectifier (Globe 80) is fine, fingers crossed !  

I think this is a lesson to avoid old Globe shape, never again.

Or it’s just a bad luck ?

Hey chakster,
I got some EML from Jac van de walle in Germany, he has pretty good stocks of tubes, even Russians, and he is very knowledgeable, the 45 is allegedly the best tube ever made for music, I am trying to get some NOS too, will let you know what I find.

EML solid plates if you like neutral sound (not mesh) is as good as it gets new production, but NOS could be less costly.

Enjoy the Amp good call

Yes, I have EML 45 tubes here in the box, but my idea was to enjoy vintage tubes before modern tubes.