This thread was intended for equivalent numbers, not specifically for sonic signatures of the tubes but... here goes:
. . . If the tubes that you can substitute for the original ones have similar specs what part of the spec makes one tube sound better than the other?
Specs do not make one tube (or any other audio device) sound better than another. If that were true tubes would not be "equivalents" If you go here you will find what is typical for tube specifications:
http://tdsl.duncanamps.com/show.php?des=6922All 6922 and equivalents have
virtually identical numbers.
Or is it really not the spec at all and just the way the tube was put together that gives it a different flavor?
I
think that is right, it is the internal structures, but that is just my opinion.
I have a vague idea that capacitors can effect bass response, what would be the analogy for tubes?
Ok, capacitors are something to swap out once you have settled on your favorite tubes. There are some that will sound better than stock but, again, everyone has different tastes so it is impossible to say for sure you will like what I like.
A larger capacitor value can extend the low frequency response in certain instances. This does not mean
enhance the bass really. In the Bottlehead designs the capacitors are large enough that you and I will never, ever hear the improvement of increasing the size of the capacitor.
I would rather not go on a quest of tube rolling even though it would be fun, but rather find a very good great sounding tube that is reliable.
New tubes should be reliable. That is what NOS tubes are and the EH are new current production tubes. There has not been a flurry of EH tube failures in the Eros. It sounds to me that they might have gotten a few bad ones recently. But over the years that the Eros has been made tube problems have been few.
In the list of tubes given above are there large differences in sonic signatures and if so which sonic signatures can you attribute to that specific tube type?
Yes, large differences are there. I haven't tried but a few. Again, what you want to hear might be different than what I'm interested in. So... start a thread in the Eros folder and tell the community what you are most interested in. There are several hundred Eros preamps out there, you will get a variety of responses.
I like the sound of the USSR Military surplus. But you and I are different people. It depends on what is most important to you. There are many attributes that tubes have. In the reasonable price category you get one or two attributes optimized. Only when you pay high prices for NOS highly sought after tubes do you get many attributes optimized.
And how does rolling the 6922's change the sonics as compared to rolling the EF86's.
I see that you do not mention the 12BH7AEH tube, why not? would not changing this tube also somehow alter the performance and sonic signature?
Lastly of all the tubes that you have rolled what would be your top 2 or 3 that you would use, please include specifics, tube type manufacturer year, NOS, where it is available etc.
As you can see I am a total noob but I also would rather shorten my learning curve dramatically with YOUR knowledge!
Sam
The 12BH7, the "AEH" is optional, is not one of the audio amplifying tubes. However Dan/Doc has changed them and found a different tube he likes. You might do a search to find that post.
The EF86 is the first tube to amplify the signal. It is the most critical. The 6922 is the last audio tube and the effect of it is less but still in the audio path.
I have had the EH tubes and the USSR surplus tubes in my Eros. No others. I had the luxury of hearing many tubes rolled through my friend's Eros. He, poster Paully, has posted throughout the Eros folder and you can find a lot of good information from his posts as well as others.
