Eros Tube Equivalents

[Grainger49]

Alex,

I will take a look at the PDF link.  Thanks.  Edit: Googled EF804S Equivalent, Found on the Tube World site (nice guy, great tubes!), now listed.  Thanks!

The 12AU7 is used in other Bottlehead products.  Paul Joppa, the designer of both Eros variants. used the 12BH7 tube, I don't think that I will list the 12AU7.

The same thing goes for the 6DJ8, Paul Joppa, states pretty plainly that it is not what the circuit is designed around.  He has said that some 6DJ8s will work as designed but not all.  I had the 6DJ8 in the list and Paul was suggesting it is not what he had had in mind in the above post.

Let's assume the 12NH7 and EF8004S are just typos?

I still don't understand what was meant by the quote of tubes that need socket rewiring.

[ALEXZ]

Grainger,
If that the post by PJ you are referring to
 ....
I generally prefer the 6922 over the 6DJ8 because the 6922 draws less heater current, withstands plate voltages over 90v better, and has better premium versions available. But they are equivalent in performance.
....
its hardly stating that Eros is not designed for 6DJ8. Maybe I'm missing something?
Also 12AU7 is not a proper substitute for 12BH7 it will work in the Eros, however will have a short life. I'm not recommending it as a substitute, I'm not putting list of recommended tubes or anything like it.
I'm just sharing  my experience with various tubes in the PS and my surprise with the change in sound quality.
To put things in context I've mentioned what are the other tubes I have in the Eros.
I'm sorry but I'm using Amperex 6DJ8 in place of 6922 and I tried 12AU7 to run for a few hours in place of 12BH7. That experiment with 12AU7 (actually Mullard cv4003) convinced me to try different tubes in the PS.
I'm not an Eros maintenance tech who recommends some questionable substitutes that could compromise this device functionality and create some unimaginable harm.  I'm just experimenting with my own amplifier.
I guess it cleared the confusion.
Thank you,
Alex

[Grainger49]

Again, this is not a tube rolling, "this is what I hear" thread.  It is a thread for exact drop in replacements and those that can be easily modified for replacement. 

That is the PJ post in this thread but elsewhere he has stated that the Eros was designed around the 6922's tighter specifications.  That an average 6DJ8 doesn't meet the design parameters so it is not suggested.  As I said, some 6DJ8s will work very well some won't.  It is like the NOS EF86 and current production EF86.  Current production will not bias properly without the servo bias circuit.  The NOS EF86 will be fine with an HLMP-6000, and quieter.  It is a distinction that keeps every one from working properly.

Read more posts in the Eros folder you will find it.

Here is the information about the EF804S.  It also seems that there is an EF804 and an EF804S so both are listed.  I hope I don't get in trouble copying this from the Tube World site but here goes (I'll call later):

In 1951 Telefunken started the 800 Series tube design and offered their improvement to the EF12 design. The EF804S is an identical version of the EF40/EF86 but with a different pin layout that offered less cross talk from the 1950 standard AC heated filament. They also used an improved cathode base material which is a nearly microphonic-proof construction with a cathode coating.  This tube was mainly used for the AEG/Telefunken Magnetophone production, but evolved into much of the professional studio equipment of the time.

First the V72 was re-equipped with this state of the art Telefunken EF804S audio tube made in their Berlin
and Ulm production. In 1967 in London, England, producer George Martin started to use EF804S equipped V72 pre amps for THE BEATLES ALBUM "SARGENT PEPPERS".