[Thomas Withers]

I was lookingh thought my EL34s and found a qaud set of Svetlala EL34 gold
tops.
there new ,I just tryed them once.Nice sound.But I like the lower sounds
better.mid and high range great..
Does Svetlana still put them out?
Found many old tubes I been collecting for years..
I even found a set of tung-sol 5881 and there NOS..lol.
Any feed back would be nice..

thomas

[Eeyore]

Thomas Withers wrote:

I was lookingh thought my EL34s and found a qaud set of Svetlala EL34 gold
tops.
there new ,I just tryed them once.Nice sound.But I like the lower sounds
better.mid and high range great..

You do realise that tubes don't have a 'frequency response' that affects the
audio band don't you. The relative levels of bass, mid and high will not be
affected by the brand of tube.

Whatever it is you're hearing it's not what you think it is.

Graham

[Iain Churches]

"Eeyore" wrote in message
...


Thomas Withers wrote:

I was lookingh thought my EL34s and found a qaud set of Svetlala EL34
gold
tops.
there new ,I just tryed them once.Nice sound.But I like the lower sounds
better.mid and high range great..

You do realise that tubes don't have a 'frequency response' that affects
the
audio band don't you. The relative levels of bass, mid and high will not
be
affected by the brand of tube.

Whatever it is you're hearing it's not what you think it is.

Graham

Graham. Are you familiar with the process of "voicing" in tube amps?
I would agree that the difference is not in frequency response, but seems
to be more concerned with distortion profile, even though THD values may
be very similar.

Your thoughts on this would be of interest
Iain

[Eeyore]

Iain Churches wrote:

"Eeyore" wrote
Thomas Withers

I was lookingh thought my EL34s and found a qaud set of Svetlala EL34
gold tops.
there new ,I just tryed them once.Nice sound.But I like the lower sounds
better.mid and high range great..

You do realise that tubes don't have a 'frequency response' that affects
the audio band don't you. The relative levels of bass, mid and high will not

be affected by the brand of tube.

Whatever it is you're hearing it's not what you think it is.

Graham. Are you familiar with the process of "voicing" in tube amps?

As I know it, in instrument amps it's about acheiving a frequency response that
'sounds nice' in its intended application as opposed to being flat.


I would agree that the difference is not in frequency response, but seems
to be more concerned with distortion profile, even though THD values may
be very similar.

Your thoughts on this would be of interest

Well, changing the operating point (and that'll happen whenever you put a new or
different set of valves in regardless of manufacturer) will certainly have an
effect on things like the transfer characteristic.

Whilst, as you say it may not register as a huge difference in numerical THD, it
may slightly affect the harmonic content.

I'm of the impression that the previous tubes were heavily aged. That would also
affect both the transfer characteristics and maximum output. I expect new tubes
might have a higher gm too and would therefore sound louder at any given volume
control setting as well as being able to 'play' louder.

I don't think there's been much discussion here of the detailed effects of tube
ageing has there ?

Graham

[Iain Churches]

"Eeyore" wrote in message
...


Iain Churches wrote:

"Eeyore" wrote
Thomas Withers

I was lookingh thought my EL34s and found a qaud set of Svetlala EL34
gold tops.
there new ,I just tryed them once.Nice sound.But I like the lower
sounds
better.mid and high range great..

You do realise that tubes don't have a 'frequency response' that
affects
the audio band don't you. The relative levels of bass, mid and high
will not

be affected by the brand of tube.

Whatever it is you're hearing it's not what you think it is.

Graham. Are you familiar with the process of "voicing" in tube amps?

As I know it, in instrument amps it's about acheiving a frequency response
that
'sounds nice' in its intended application as opposed to being flat.

Most of the people I know who build tube amps (instrument and
also hi-fi) spend time in voicing.

When he was technical director at Svetlana, Eric Barbour
did some interesting comparisons of double triodes, and
correlated what he had found with listening tests.
He sent me the results. I will try to dig them out, if anyone
is interested. I wanted to hear this for myself, and although
I could not obtain all ten brands of the tubes he had listed,
I managed to obtain six or so. I too saw what he had seen
in spectral analysis, and the group of people with whom I
was listening noticed differences, although we did not
necessarily put them in the same order as Eric's team had done.

I don't think there's been much discussion here of the detailed effects of
tube ageing has there ?

People I know change tubes usually by calculating roughly
the number of hours they have run (10 000 for small signal
and 3 000 for power tubes) and then thinking "time they
were changed"

Some boutique builders send out a reminder after
three years, and change the tubes as a part of the warranty
(work included, but tubes charged at retail:-)

In instrument amps, heater failure or cathode to heater shorts
seem not uncommon, probably due to the harder physical use
that these amps are submitted to. Many noisy tubes are not
actually noisy at all. After the pins are cleaned, and the tube
socket cleaned and tightened, problems often disappear.

Other than decreasing gm, how does tube ageing manifest
itself? People reset the bias on fixed bias amps, at regular
intervals so small changes may not be noticeable.

Over to you, Graham. New thread?

Iain

[Eeyore]

Iain Churches wrote:

"Eeyore" wrote

Other than decreasing gm, how does tube ageing manifest
itself?

Cathode efficiency eventually drops off so the tube's ability to carry higher
currents is reduced. It may also manifest itself as a higher plate resistance
although I'm not sure of the details of that.


People reset the bias on fixed bias amps, at regular
intervals so small changes may not be noticeable.

That would certainly mask it.


Over to you, Graham. New thread?

This one works for me for now.

Graham

[GerryE123]

Thomas:

I had a quad back in the mid-1990s. IIRC, there was some kind of production
problem with them. Therefore, they were only made for a very short time.
It was mostly a gimmick. No better or worse than the others EL34s they were
making at the time.

Gerry

"Thomas Withers" wrote in message
et...
I was lookingh thought my EL34s and found a qaud set of Svetlala EL34 gold
tops.
there new ,I just tryed them once.Nice sound.But I like the lower sounds
better.mid and high range great..
Does Svetlana still put them out?
Found many old tubes I been collecting for years..
I even found a set of tung-sol 5881 and there NOS..lol.
Any feed back would be nice..

thomas