• To directly access the forum, ensure your bookmark url includes /forum.

Opamps and DACs, and Border patrol SE

dave

incurable tinkerer
Wammer
Mar 24, 2014
1,415
741
148
cambs
AKA
dave
HiFi Trade?
  1. No
Been puzzled by the Border patrol SE DAC, its curious tube rectifier. and ultra minimal TDA1543 implementation for a while, but have been skewered recently by pilsonaught ('s interesting crossover adventure)


and simultaneously Mr flash invoking this review:,


in the border Patrol SE for sale in the classified, which puts the boarder patrol in the same ballpark ac the DCS Rossini!

Now I know a bit about the 1543, and has been my dac chip of choice (cheap and plentiful) for most of the last 24 years, and I have designed 3 discrete, one with transistors, and 2 tube, current to voltage converters for it, all of which give very satisfactory results.

of late however, now I have some speakers with decent tweeters, become just a little bit aware of the NOS's shortcomings

It was interesting therefore to find another review, in Stereophile, and in particular theis 2nd opinion:


In my rig I now have a Denon DVD2900 (DSD1790 bit stream and opamps) and my homemade eternal CD player with NOS1543 and tube i/v.

The observations made by John Ivertson parallel my own completely.

On its own the 2900 sounds detailed but a bit thin in my rig and not really very nice to listen to, in comparison to my 1543 which is lush and timbral detail and lovely, but a bit obscured on the finest of details.

end of part 1
 

dave

incurable tinkerer
Wammer
Mar 24, 2014
1,415
741
148
cambs
AKA
dave
HiFi Trade?
  1. No
I have an active wire, which I plugged into the back of the 2900, and long story short, transformed the sound from the 2900 to heavenly bliss, on a similar level to the 1543, but with better fine detail and top, but curiously the tubed 1543 has better bass timbre.

But what of the BP SE

https://forum.hifiguides.com/upload...c1f851e8c9c7ffe863fc27b13b37bfac3f42d5f0.jpeg

from somewhere in https://forum.hifiguides.com/

I feel a little disappointed and bemused by the innards. cobbled together from chinese kit parts, the 1543 running sub optimally from a distortion perspective in to a 2k3 resistor (I presume) for i/v and then off through some premium output caps to remove the 2.1 volt DC offset. I see no opamps.

So what is the going on. a simple dac chip with a resistor i/v, is in the same ballpark as a DCS... which I would be very confident has opamps, and a greatly superior DAC chip. I really don't understand what difference a EZ80 should make either

https://www.hifinews.com/images/1119dcs.ins.jpg

from https://www.hifinews.com/content/dcs-rossini-transportdac-v2-sacd-transportdac

one does wonder what levels of sonic ecstasy could be reached if the DCS had a well implemented tube output.

Which brings me back to my active wire, (call it a discrete buffer for simplicity). to add to the mystery, in my mainly valve rig everything goes through a stock Behringer DEQ2496, bristling with cheap opamps and ADC /DAC. I can easily hear the difference between the DVD2900, and my 1543 NOS Tube CD player, and my record player for that matter through the beringer, which to me seems pretty transparent (unlike DCX2496).

So a paradox I am confident that buffering the output of the DVD2900, has revealed the lovely sounds coming from bitstreen DACs, through the opamps, but I can here this through the Behringer's inferior op amps.
I am puzzled but suspicious of opamps, especially around DACS.
 

rabski

Everything in moderation
Staff member
Dec 2, 2006
33,746
21,626
173
Kettering
AKA
Richard
HiFi Trade?
  1. No
Try the AD1865, is all I would suggest. To my ears, the step up from TDA1543 to AD1865 fills in all the missing pieces.

The only problem these days is getting hold of genuine chips. The 1865 has been out of production for ages and well-known auction sites are rife with copies.
 

dave

incurable tinkerer
Wammer
Mar 24, 2014
1,415
741
148
cambs
AKA
dave
HiFi Trade?
  1. No
oh my epic post, can't seem to post pictures from links like in the old forum.