Schiit SYS-49 and phono preamp with or without attenuator?

[355F1]

Hi,

I recently acquired a Schiit SYS 49 volume control. I have a choice to purchase a phono preamp either with an attenuator or without it.

In case that I get the former, which attenuator or volume pot takes precedence, the one in the Schiit or the one in the head amp?

Cheers,

 

[rayma]

If the phono preamp has a 10k volume control, it will drive the output cables and the passive box fine.
Then you can use either control as you prefer.

But if the phono control is 100k up, instead turn it to maximum and use the volume control in the passive box,
which does have a 10k control. However, it is possible that the passive box 10k control could load down
the phono preamp circuit more than is intended, if it is tube based. In that case, only use the phono
volume control and keep the passive box control at maximum when using the phono. Of course,
you will use the passive box control when playing CDs.

 

[355F1]

I can replace the SYS with a Goldpoint SA2-47 attenuator. The factory offered me to replace the 25K attenuator with either a 50K or a 100K.

I do not have the knowledge to make a decision about that.

How about a tube preamp, still won't work with the Goldpoint either.

 

[rayma]

First make the decision whether to keep the new phono stage.
Then determine the impedance value of the volume control inside it.
The issue is the control impedance, not what kind of control it is.

If the value of the control inside the phono stage is 10k, that is fine.
If the value is higher, that is problematic to drive the passive box 10k impedance.

It may also be problematic for the phono stage to be loaded with the
passive box 10k control, even if you use the passive box as the volume control,
with the phono volume control at maximum. It would be ideal to have the schematic
of the phono stage to help decide.

Generally, a tube source will require a tube line amplifier, because a tube line amplifier
will have a 100k or higher volume control, which is the proper load for a tube source.
A solid state line amplifier will usually have a 10k volume control, which is generally
too low for tube based sources. There can be exceptions, such as a buffered solid state
output stage in a tube source component.

 

[355F1]

Hi Rayma,

Thanks much for the info, super interesting for an old newbie.

I still did not buy a preamp or phono stage. There is little info about the units I have in mind, there are no schematics available.

I recently bought a Berning ZH-230 OTL amplifier. It does not have a volume control.

It is a prototype, Berning recycled a face plate from an EA-230 amp, but the real story is on the back of the amp in Berning's purple marks-a-lot. Operates identically to the production model, including the ability to mix and match 12au7, 12at7, and 12ax7 input and driver tubes to implement different feedback, output impedance, and distortion characteristics.

Please see pictures.

OTOMON Laboratory　(音門ラボ) / Preamplifiers

 

[rayma]

Very nice, his original prototype amplifier.

You could own more than one component of each type,
or even more than one system. I certainly do.

 

[355F1]

One is more than enough for me, I spent 57 years chasing an audio nirvana, I am 76 now and will be content to find a decent photo stage. If I get the Uesugi UBROS-1 full feature preamp, photo 1, I'll resell the Schiit for a few bucks.

If I was sure that the Otomon Ken Uesugi phono stage will work I would buy it, it costs half the price of the UBROS-1.

What a mess!!!

 

[rayma]

Looks like you are about to drop a lot of coin, but that may not be necessary.
Read some of the reviews on Fremer's web site. He is highly respected, and
has heard most of the phono stages (and cartridges) that have been in commercial production.
I like tube electronics also, but solid state phono stages can be at the highest level.
Phono Preamp Reviews | Analog Planet

 

[355F1]

Seems to be a decent phono stage for $350.

Musical Surroundings Phonomena II | Phono | Audiogon