[TJHUB]

I've been rolling tubes in my Music Hall DAC and I'm looking to try some more.  However, my favorite tube is branded RCA and I'd like to be certain of just what it is so that I can identify some different tubes to try.

Is this an Amperex?











Thanks.

[jules]

Yes, looks like Amperex from Heerlen Holland but if you want a bit more detail, read the etched details at the bottom of the tube in the first pic. This will give you the year of manufacture and also have a symbol indicating factory of manufacture. There are different variations of the design and it's best to get pairs that are at least of the same type/year.

If you like these tubes you'll probably like the orange globe logo Amperex with either this internal design or the later A frame. They're a very good tube and don't demand the stratospheric price of others from the same manufacturer.

jules

[TJHUB]

Yes, looks like Amperex from Heerlen Holland but if you want a bit more detail, read the etched details at the bottom of the tube in the first pic. This will give you the year of manufacture and also have a symbol indicating factory of manufacture. There are different variations of the design and it's best to get pairs that are at least of the same type/year.

If you like these tubes you'll probably like the orange globe logo Amperex with either this internal design or the later A frame. They're a very good tube and don't demand the stratospheric price of others from the same manufacturer.

jules

Thanks jules.  From the little I know, I thought this was an early Amperex tube.  It was given to me from an acquaintance on another forum to try out and at first I didn't like it.  It was VERY bass heavy.  The strange thing is that the second time I tried it, I let it run for about 36 hours before listening to it again.  The bass heaviness is now gone.  It's really a nice sounding tube.

I also have Tesla that is pretty good.  It has a little better midbass output making is sound more balanced on the low end.  I'm not certain which tube is more articulate in the bass region, but I'd like to hear better than either of these tubes.  The Tesla is also not as extended in the highs as the RCA branded tube, but other than that it is VERY good. 

I'd like a tube that is a little more airy on top, a midrange similar to the RCA branded tube, and a tighter, more accurate bass output.  From what I've been reading, it would seem a Siemens tube would be worth trying.  I want to order something tomorrow if possible.   

[planet10]

Given that it is labeled RCA, calling it a Philips tube is more accurate.

Many Amperex tubes were made by Philips, but so were Mullards, Valvos and more...

dave

[jules]

Yes TJHUB, a Siemens is a good choice. These and Telefunken are great tubes and very accurate as well.

There were  quite a variety of different Siemens tubes produced over the years and almost all of them are good. Some of the very late ones are not but if the internal design is like this:



you're pretty safe. The A frames are ok as well but beware of single getter tubes
 


like these supposedly late Telefunkens. There are Siemens of the same design and neither type is noteworthy.

Yes planet10, I largely agree with you though Amperex was the name generally given to Phillips tubes exported to the US but then RCA was US badge engineering too, so it's still a bit murky isn't it  .  It might have been much simpler if they'd just put Phillips on all of their tubes but then we wouldn't have been able to pick up the odd bargain of an an Amperex labelled RCA or even a Siemens labelled RCA etc

jules

[TJHUB]

I spoke on the phone with a tube vendor this morning for about 20 minutes explaining both what I hear now with the RCA branded tube and what I would ultimately like to hear.  He recommended I try a Mazda 7308 tube made in France.  Hopefully the French have what I'm looking for...

Thanks again for your help. 

[jules]

Sounds like you're getting good advice. Perhaps you could post a pic here when you get the tubes.

If you also post the numbers/letters/symbols etched in the glass of the Amperex and the Mazda it should be possible to give you details such as factory of manufacture, year, month and batch. This often tells you more than the painted on stuff.

jules

[TJHUB]

Sounds like you're getting good advice. Perhaps you could post a pic here when you get the tubes.

If you also post the numbers/letters/symbols etched in the glass of the Amperex and the Mazda it should be possible to give you details such as factory of manufacture, year, month and batch. This often tells you more than the painted on stuff.

jules

Thank goodness you said I was getting "good" advise.  I wouldn't know, so I knew I was taking a gamble.  The nice thing is that I now have a little experience to at least tell these guys what I hear now and what I'd like to hear.  Helps a lot!

I'd be happy to post pics of the tubes to identify what they are exactly.  It helps further my knowledge into this very confusing world of tubes.  At first I thought I made a big mistake when I listened to a bad tube (a Telefunken no less).  It was scary until I heard the Tesla and things got back on track.  Then this Amperex tube took things a step up and now I hope this Mazda tube will be the one.  I at least now have no regrets giving tubes a shot.  As a matter of fact, I don't think I could go back to not at least having this tube DAC in my setup.  LOVE IT!! 

[jules]

I hope this Mazda tube will be the one. 

In your dreams   ! Part of the fun is trying a few tubes to find out what your preferences are. There do seem to be two camps of enthusiasts, the Philips/ Amperex fans and the Siemens/Telefunken supporters.

If you like the Amperex sound, you might like to work your way up that chain. If you haven't already browsed your way through this site, have a look at what's available:

https://www.tubeworld.com/7308.htm

You could pick up a pair of 1959 Philips SQ with D getters for a mere $750 or not!

jules

[TJHUB]

I hope this Mazda tube will be the one. 

In your dreams   ! Part of the fun is trying a few tubes to find out what your preferences are. There do seem to be two camps of enthusiasts, the Philips/ Amperex fans and the Siemens/Telefunken supporters.

If you like the Amperex sound, you might like to work your way up that chain. If you haven't already browsed your way through this site, have a look at what's available:

https://www.tubeworld.com/7308.htm

You could pick up a pair of 1959 Philips SQ with D getters for a mere $750 or not!

jules

Don't kill my dream!    The Mazda will be the one!

My first couple of tubes are from Brendan as Tube World is local to me.  I actually picked the tubes up from Brendan directly at his facility.  He is a helpful guy and nice to work with, but it was tough for him to help someone with no experience with tubes.  Also, he's not afraid to charge a lot. 

[bunnyma357]

While you're still experimenting, I'd suggest trying the 6N23P Russian tubes from the Voskhod factory (Rocket Logo), it is my favorite 6922/6DJ8/7308 variant in my integrated amp, with my current tube complement. I liked it better than the Holland Amperex A-Frames, Holland Amperex PQ's, USA Amperex PQ's, NOS Teslas, and Reflektor 6N23P-EV's that I've tried.

Several tube vendors have them, or they are pretty available on eBay  -  and they are relatively cheap. May not work in your set up, but has been a pleasant surprise in mine.


Jim C

[TJHUB]

While you're still experimenting, I'd suggest trying the 6N23P Russian tubes from the Voskhod factory (Rocket Logo), it is my favorite 6922/6DJ8/7308 variant in my integrated amp, with my current tube complement. I liked it better than the Holland Amperex A-Frames, Holland Amperex PQ's, USA Amperex PQ's, NOS Teslas, and Reflektor 6N23P-EV's that I've tried.

Several tube vendors have them, or they are pretty available on eBay  -  and they are relatively cheap. May not work in your set up, but has been a pleasant surprise in mine.


Jim C

Jim,

What do these tubes sound like compared to the Amperex's or Tesla?  What qualities do they possess with your amp?

[bunnyma357]

Jim,

What do these tubes sound like compared to the Amperex's or Tesla?  What qualities do they possess with your amp?

I had posted this comparison in another thread, so I'll repost it here. The interesting thing is that in a previous configuration I had preferred the Amperex USA PQ 6922, so the synergy between tubes is pretty important.

Here are my quick impressions of the various 6DJ8 type tubes I have running in my Onix SP3.  The other slots are:

RFT ECC81 (NOS) (12AT7 type tube in place of a 12AX7)
RFT 12AU7 (NOS)
Reflektor 6P3S-E (NOS)  (Coin base tubes 6L6 alternative, supposed to be from Reflektor factory, but there is no factory logo, so I'm sure)

Voskhod 6n23p (NOS)  -  Natural realistic sound, treble through bass sound connected, soundstage is moderately wide and deep - again sounds appropriate.

Amperex USA PQ 6922 (NOS) -  Has more detail and air, wider soundstage, but maybe a little less deep. High end seems slightly grating, increased presence seems to make solo performers sound bigger than the perspective you'd expect. More impressive, but less natural. Overall thinner presentation, lower mids and bass sound a little tinny - less harmonics and resonances.

Tesla E88CC (NOS - Not JJ)  -  Similar to the Vokshods, but with a smaller presentation both width & depth, and a little less high end "presence", cymbal crashes seem to end a little less naturally. Very nice and natural sounding, just slightly flat - not as involving as the Voskhods.

Amperex Holland 6DJ8 A-Frame (Used in good shape)  -  Wide soundstage, but less depth, sounds a little unnatural on the size of instruments - "10 ft. wide piano", not a lot of presence or sense of space or air around vocalist and instruments, sounds a little flat. A little thin in the lower mids and bass. Very forward direct presentation - not romantic or lush. Sounds really good on some recordings, and just average on others.

Amperex Holland PQ 6922 (Used - a little less matched pair than some of the others)  -  A little flat on the high frequencies, deep soundstage but some what unnatural some vocals too far back, keyboards too far forward. Width is much less than some of the others, doesn't seem to go much beyond the speakers. Again a very direct presentation, with less of a sense of space.
Also seems to work better with some recordings more than others. Seemed to take longer to warm up and become "sweet" sounding than some of the others.

Reflektor 6n23p-ev (NOS)  -  Transients seem a little crisper, sound is a slight bit grating and a little less smooth. Natural sounding presentation, soundstage depth and positioning feel correct - a little less wide than some of the others. Not a lot of presence or sense of harmonics & resonances.

Melody 6922  (Chinese tubes that came with the amp)  -  Sounds like a scaled down presentation, less depth dynamics, and less able to separate the instruments accross the soundstage. A little laidback and not the same you are there presence as the others.

After this quick test I'd rank them as follows:

1) Voskhod 6n23p
2) Amperex Holland 6DJ8 A-Frame
3) Tesla E88CC
4) Amperex Holland PQ 6922
5) Reflektor 6n23p-ev
6) Amperex USA PQ 6922
7) Melody 6922


These impressions and preferences are definitely different than when I was running the amp with GE 3MBP 5751 (NOS),  RFT 12AU7 (NOS), and Valve Art 350B's (New Production) in the other slots, so how the tubes interact is clearly a factor.

Jim C

[TJHUB]

Jim,

What do these tubes sound like compared to the Amperex's or Tesla?  What qualities do they possess with your amp?

I had posted this comparison in another thread, so I'll repost it here. The interesting thing is that in a previous configuration I had preferred the Amperex USA PQ 6922, so the synergy between tubes is pretty important.

Here are my quick impressions of the various 6DJ8 type tubes I have running in my Onix SP3.  The other slots are:

RFT ECC81 (NOS) (12AT7 type tube in place of a 12AX7)
RFT 12AU7 (NOS)
Reflektor 6P3S-E (NOS)  (Coin base tubes 6L6 alternative, supposed to be from Reflektor factory, but there is no factory logo, so I'm sure)

Voskhod 6n23p (NOS)  -  Natural realistic sound, treble through bass sound connected, soundstage is moderately wide and deep - again sounds appropriate.

Amperex USA PQ 6922 (NOS) -  Has more detail and air, wider soundstage, but maybe a little less deep. High end seems slightly grating, increased presence seems to make solo performers sound bigger than the perspective you'd expect. More impressive, but less natural. Overall thinner presentation, lower mids and bass sound a little tinny - less harmonics and resonances.

Tesla E88CC (NOS - Not JJ)  -  Similar to the Vokshods, but with a smaller presentation both width & depth, and a little less high end "presence", cymbal crashes seem to end a little less naturally. Very nice and natural sounding, just slightly flat - not as involving as the Voskhods.

Amperex Holland 6DJ8 A-Frame (Used in good shape)  -  Wide soundstage, but less depth, sounds a little unnatural on the size of instruments - "10 ft. wide piano", not a lot of presence or sense of space or air around vocalist and instruments, sounds a little flat. A little thin in the lower mids and bass. Very forward direct presentation - not romantic or lush. Sounds really good on some recordings, and just average on others.

Amperex Holland PQ 6922 (Used - a little less matched pair than some of the others)  -  A little flat on the high frequencies, deep soundstage but some what unnatural some vocals too far back, keyboards too far forward. Width is much less than some of the others, doesn't seem to go much beyond the speakers. Again a very direct presentation, with less of a sense of space.
Also seems to work better with some recordings more than others. Seemed to take longer to warm up and become "sweet" sounding than some of the others.

Reflektor 6n23p-ev (NOS)  -  Transients seem a little crisper, sound is a slight bit grating and a little less smooth. Natural sounding presentation, soundstage depth and positioning feel correct - a little less wide than some of the others. Not a lot of presence or sense of harmonics & resonances.

Melody 6922  (Chinese tubes that came with the amp)  -  Sounds like a scaled down presentation, less depth dynamics, and less able to separate the instruments accross the soundstage. A little laidback and not the same you are there presence as the others.

After this quick test I'd rank them as follows:

1) Voskhod 6n23p
2) Amperex Holland 6DJ8 A-Frame
3) Tesla E88CC
4) Amperex Holland PQ 6922
5) Reflektor 6n23p-ev
6) Amperex USA PQ 6922
7) Melody 6922


These impressions and preferences are definitely different than when I was running the amp with GE 3MBP 5751 (NOS),  RFT 12AU7 (NOS), and Valve Art 350B's (New Production) in the other slots, so how the tubes interact is clearly a factor.

Jim C

Jim,

Thanks for the repost.  The Voskhods sound interesting from your description.  I did a quick search and found a place selling them for $12.00.  Does this sound right to you?  For that cheap, I may just have to try one.

I don't know just how different are two pieces of gear sound with these various tubes, but I think your description of the Tesla E88CC is exactly what I think of mine.  I liked the tube mostly for it's midrange and bass presentations, but the high end is a little flat for my tastes.  It's very listenable, but it's just not what I'm looking for.

The Amperex I'm running now has better extension on the top end and decay of cymbals is better than the Tesla.  The lower midrange or upper bass is thin sounding compared to the Tesla.  I do seem to prefer the Amperex tube I have over any other tube I've heard. 

Bassed on the vendor's comments of the Mazda tube I have on order, I think it's going to be what I'm looking for.  He stated I should hear more attack on the upper end with a smooth midrange and tight, controlled bass (paraphrasing here a bit).  Sounds perfect for me!  I can't wait to give it a listen.

[ltr317]

Not only is the synergy between tubes important, but the interaction of a tube to a particular circuit is even more important.  As someone on another audio forum once brilliantly said, " There's a circuit for every tube, and a tube for every circuit."

Paul

[bunnyma357]

Jim,

Thanks for the repost.  The Voskhods sound interesting from your description.  I did a quick search and found a place selling them for $12.00.  Does this sound right to you?  For that cheap, I may just have to try one.

That seems reasonable for a vendor who has imported them, I bought mine directly from one of the Soviet countries on eBay for about $6 ea. shipped. I've had pretty good experiences buying surplus Russian tubes on eBay, but there certainly is a lot less risk buying them from a vendor you trust.

For the price it just seems like they are worth a try, I certainly wasn't expecting to like them better than the substantially more expensive tubes I'd already bought.

Jim C

[TJHUB]

I just received the Mazda 7308 (1972 NOS) tube.  WOW, another big step in the right direction.  I only have an hour on this tube, but it sounds wonderful.  The transients are probably the most obvious improvement over the other tubes I've listened to or own.  There is a great attack to the the upper end.  The tube's overall presentation is very clear.  Tight sounding bass, clear midrange, and extended highs with nice decay.  Instruments sound natural and real.  The best thing of all is the bass is much more articulate with very nice midbass!  I hope this tube doesn't break in to something less.  I really hope it only gets better!!

Just wanted to share...

[doctorcilantro]

Many Mazda tubes were made in Holland. Etch codes "F" and the +- (these last two characters above one another) were for the plants in France (owned by Amperex Philips) in Sursenses and a few other places I can't remember of the top of my head. Still, the French tubes, made in France, were given there own etch codes. How different they really are given the Amperex Philips "owned" Mazda is up in the air. I have heard many reports that the French-made E188CC betters the Holland-made ones; the jury is still out.

What etch codes are on the Mazda branded E188CC you received?

DC

[doctorcilantro]

[S Clark]

Thanks for the chart, Dr. C.  I printed it out and now have it stashed with my tubes.