Don Sachs SP14 Tube Preamp Review

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mresseguie

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  • D Sachs amp/pre + Daedalus Audio Speakers = HEAVEN
Re: Don Sachs SP14 Tube Preamp Review
« Reply #501 on: 24 Jul 2018, 01:56 am »
Have you got any more details on it? Could it be a VTA SP14?

It appears to have a nice complement of upgraded caps. I do not know how they compare to Jupiter or Dueland caps.

What information are you seeking?


aguaazul

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #502 on: 24 Jul 2018, 02:00 am »
Looks like the VTA SP-14. Has the older style Khozmo wireless remote. 2 sets of output caps. Some beefy power supply caps for sure. Nicely wired also.

Lazz

Re: Don Sachs SP14 Tube Preamp Review
« Reply #503 on: 24 Jul 2018, 11:11 am »
Yes the front does say vacumn tube audio. Don't know anything about it. It popped up in facebook images. Thx for the replies.

Lazz

Re: Don Sachs SP14 Tube Preamp Review
« Reply #504 on: 29 Jul 2018, 03:04 pm »
Can someone tell me how is the DS able to have the tubes sticking out of the case as opposed to the Roy Mottram where they are on the board and inside the case?

genjamon

Re: Don Sachs SP14 Tube Preamp Review
« Reply #505 on: 29 Jul 2018, 03:07 pm »
The DS version is the circuit board mounted upside down against the top cover of the case. And the tube sockets are mounted to the bottom side of the board rather than the top, thus facing the top part of the case.

Lazz

Re: Don Sachs SP14 Tube Preamp Review
« Reply #506 on: 7 Aug 2018, 11:25 pm »
HI
That cap calculator is nonsense.  They want you to assume that the LF rolloff will start at 10X the value of the -3 dB point. They want to sell you a large and expensive cap.  The reality of it is that 3 octaves is plenty and 2 octaves is really sufficient.  An octave is 2X the frequency value.  So even 3 octaves is only 8X.   If you keep the - 3 dB point below 5 Hz I seriously doubt you will hear any LF loss into your amp.  If you really want to drive a 10K load then you can go 3 uF.  Into 10K to get a 5 Hz -3dB point you need 3.185 uF of capacitance.   So 3 uF is fine.  The thing is, that besides cost, there is a tradeoff in sonic quality between values as you get a larger cap value.  More phase error, etc...  I cannot hear any difference in cap sizes up to about 3 uF.  If I put a 4.7 uF cap in I don't think it sounds quite as good.  So you are using a larger cap to avoid any rolloff at all below 20 Hz and giving up sound quality.  The reality is that there is little if any music below 25-30 Hz unless you are into electronica or Bach organ fugues.  Piano goes down to 27.5 Hz and bass about 30 Hz.  Also, most people don't have speakers that will play below 30-35Hz.   So if you use a 3 uF cap you might get a smidge of LF rolloff into 10K between 20 and 35 Hz, but your speakers and the music itself don't go down there anyway.  So you put a 4.7 uF cap in the preamp to get performance you don't need and it doesn't sound quite as good as the 2 or 3 uF cap.   

Quite frankly I never understood why on Earth a manufacturer would make ANY amp with a 10K input impedance.  There are plenty of good SS amps out there with 47K input impedance and some are 100K.  It has nothing to do with SS vs. tube.  Any tube amp I have ever seen is 80K or higher and most are 100K.   My KT88 amp is 220K.   If I am building an amp and matching preamp for a customer I use .33 uF caps.  That gives a -3 dB point of 2.2 Hz and a nice small output cap.

What would be the optimum cap value for my monoblocks. They state "INPUT IMPEDANCE : 130kOhms in parallel with 82pF". I have very large full range speakers can play down to 20hz. Thx.

A_shah

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #507 on: 8 Aug 2018, 04:28 am »
What would be the optimum cap value for my monoblocks. They state "INPUT IMPEDANCE : 130kOhms in parallel with 82pF". I have very large full range speakers can play down to 20hz. Thx.


My DS- 2 does go down to 20 HZ flat as per Don ,  best call Don and ask him  I have two sets of caps 1 set is the Jupiter 1 Uf and the 2nd set is audiocap theta with Russian bypass Teflon  3.uf caps both are very sweet sounding I use the jupiter with my quicksilver tube  mono 60 and the 3 uf when I use Odyssey SS amp.my Daedalus  Poseidon go from 28hz- to 24K hz.

Asghar 


bluemeanies

Re: Don Sachs SP14 Tube Preamp Review
« Reply #508 on: 18 Aug 2018, 11:27 am »
Back on TOPIC
I have the SP14!
Custom job but NOT from DS.
I am using the Shaugang Treasure 181Z for the gain AND buffer positions.
How sweet thy sound!

For the money and just the idea of this pre-amp I feel it compares with pre-amps costing in the $10,000 range. Some may disagree but that is how I feel about this unit. Togather with my Audionote 4.1LE tube Dac.
Amazing LIFELIKE sound, bigger bass and soundstage.
The midrange is superlative...sublime.
I was really impress with gaining a better soundstage since my room has a ceiling height of only 7'&6'4".

Well worth the investment..I paid to have it assembled but it was worth it.
No hum. Quiet as a mouse.

kbuzz3

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #509 on: 9 Oct 2018, 06:53 pm »
Those isolation devices are not exactly or even remotely attractive or inconspicuous!

I'll stick with the Herbie's Tenderfoot!

how did you find using using herbies tenderfeet on your sub? The reason i ask is I have some lying around but herbies usually recommends other materials for subs....like big fat dot etc.