AD797 Phono Stage Build and Help Desk Thread

[tabarddn51]

Hi, I have not heard the 1611, but reviews are good & price is very good, will give a pair a go & see how they sound.

Cheers

 

[Duclasi]

After a few records with the Vishay MKPs decided to replace them with something else. I had the opportunity to take over a set of NOS Siemens capacitors. This afternoon I picked them up and of course immediately assembled them tonight.

Where there was a somewhat hard edge with the MKPs, that has now completely disappeared. Even in the current trial setup this already plays way better compared to many phono amps in my opinion. In addition to a more natural sound, the emotional involvement is also greater with the new capacitors.



For the power supply, there will soon be an EI-Core transformer from AE in Schagen (NL) that will be poured in and shielded. When it meets the test setup, I will continue to look at installing it in a nice housing

 

[Duclasi]

Recently I made some upgrades. The 47R and 390R resistors in the signal path have been replaced for Takman Rex. and Shinkoh tantalum. Gain has also been replaced bij Shinkoh Tantalum. Next step will be Caddock MK232 resistors at the input and Panasonic FC 10uF to replace the FR caps.






I’m also considering to us a shunt regulated PSU for each opamp. Is there anybody who also tried this kind of power supply?

 

[loudnoises]

I just stumbled upon a set of boards, seems I bought a second set! Yay me.

I built mine back before covid, are there any revisions I may have missed? Thinking of building up a second preamp with maybe more boutique components...

 

[tabarddn51]

Hi, There are several upgrades worth doing.
- Upgrading output capacitor. I prefer the CORNELL DUBILIER 940C, others the Russian caps. I think it really depends of what cart & system you have.

- Upgrades by Wyn Palmer may worth doing, But I have not bothered with that.

- Power supply, I am using the battery driven Super Regulator from DIYaudio. (note to get the best out of it, it must be battery driven)

Super Regulator

This thread is for discussions about the Power Supply Super Regulator which is now available for pre-order. You can read Jan's introduction to the Super Regulator in his blog, then check out the Super Regulator Article over at Linear Audio and discuss it in this thread right here. Change...

www.diyaudio.com

- The resistor upgrades just shown by Duclasi are interesting.





Have fun

Cheers

 

[loudnoises]

Well it's happened again, opa2134 in my ad797 have again burned out. This time one seems to be brassy and another dull. Once I figured it out, a quick swap in of new amps and we're all good again.

So a fair warning, if you leave it on 24/7, you may need to replace your opamps every 4-5 years. If you find some you like, have a pair on hand.

Ymmv.

 

[tabarddn51]

Hi, One of the penalties of leaving equipment on all the time. I turn my equipment on about 15 to 30 minutes before I start serious listening.

last year a guy here in NZ burnt his $6000 TV out in 18 months because he left it on 24/7. It had a 5 year warranty, but the manufacturer refused to to replace it when the guy foolishly told the dealer how he used it.

Cheers

 

[mkane]

I don't think botique parts will alter the sound.

 

[tabarddn51]

Hi, Well the output capacitor & op-amps definitely do. But in the past I have read of people building well known P/Amps with expensive parts & then advising they could not hear the difference.
I have also heard of people changing the variable resistors (I like the versatility) to fixed & again the majority report they could not hear any difference.

But it really depends on what your front end is & if the arm & cart is of a high enough quality to read & portray what is being played from the LP grooves.

Cheers

 

[Duclasi]

Yesterday I finished my Hypno with dual Salas shunt PSU and separated transformer and rectifier.

 

[tabarddn51]

Hi, Well done, a very impressive build.

I am just trialing a pair of these in my second stage

https://www.aliexpress.com/item/1005009781211743.html?spm=a2g0o.productlist.main.1.6a16l1Yyl1Yy7M&algo_pvid=80a1c83a-f32d-4db8-9904-5e159b5c9e19&algo_exp_id=80a1c83a-f32d-4db8-9904-5e159b5c9e19-0&pdp_ext_f=%7B%22order%22%3A%227%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis%21NZD%2121.11%2114.78%21%21%2112.11%218.48%21%402101e81117815006187628771e14ce%2112000058398803806%21sea%21NZ%21161172495%21X%211%210%21n_tag%3A-29919%3Bd%3A31829955%3Bm03_new_user%3A-29895&curPageLogUid=f5MxsoaKewMA&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005009781211743%7C_p_origin_prod%3A&tblci=GiD-8zV05hl8cJAfXfbYFFlSulynHzLf-zqKlgq6d01TpCDwjE4ovMW6uOuv9f_2ATDx_D4

Very impressive, easily as good as the V6's I have been using at a fraction of the cost.

Cheers

 

[Duclasi]

Anyone experience with different discrete Opamps on the Lm49990 position? I’m using OPA 1611 for now, but I’m looking voor some discrete opamp to replace them. At this moment I’m thinking about buying a pair of Staccato Audio OSH discrete Opamps.

 

[Duclasi]

When replacing the OPA1611 or LM49990 for a discrete OpAmp with lower bandwidth, do I need to change those 10uF capacitors and parallel ceramic caps for different values?

 

[sachu888]

No, you don't need to change anything.

Regards
Sachin

 

[Duclasi]

Yesterday I replaced the OPA-1611 Opamps for discrete Stacatto OSH-S Opamps. Recommended burn in time for those Opamps is 24H, so it will take some time to review them.

I also adjusted the power supply, because the Staccato runs in class A. Power consumption is now 40mA for each channel.