The Phonoclone and VSPS PCB Help Desk

[Mr Onion]

Why didn't you change IC1? I believe IC1 have more impact on the sound.
I use LT1028 in 1 and AD797 in 2. Very nice. I must try the LME49710 in 3 & 4 when I get home.

The Phonoclone IC1 is a little different: this is a low noise, low impedance application so the OPA27 or equivalent (usually marketed as "low noise, precision") op amps are possibly more desirable over the for-audio types, the latter being typically optimized for slightly higher input impedance.

... so I left IC 1 as the BoM. I'll have a look at the LT1028

 

[vulejov]

AD797 sounds better than LT1028..

 

[Mr Onion]

AD797 sounds better than LT1028..

... but will it work as IC 1?

 

[vulejov]

... but will it work as IC 1?

Of course it will..

No need to use two opamps for MC phono.. single chip works perfectly with 60-65db gain.. I tried with LME49710, LT1028 and AD797.. use VSPS board, circuit is identical, only values are different..

 

[Mr Onion]

Of course it will..

No need to use two opamps for MC phono.. single chip works perfectly with 60-65db gain.. I tried with LME49710, LT1028 and AD797.. use VSPS board, circuit is identical, only values are different..

I only ask as Richard has stated:-

The Phonoclone IC1 is a little different: this is a low noise, low impedance application so the OPA27 or equivalent (usually marketed as "low noise, precision") op amps are possibly more desirable over the for-audio types, the latter being typically optimized for slightly higher input impedance.

 

[Mr Onion]

I've ordered 5 797's (FIVE I hear you ask. 5 cost less than 4, and 5 only cost £5 more than 2)

I'll have plenty of Op Amps to play with then, and I'll post my findings once I have found them

 

[vulejov]

I've ordered 5 797's..

You only need two..

Single-opamp MC phono plays much better than phonoclone..

 

[Mr Onion]

You only need two..

I know, but the pricing was such that buying 5 made more sense

 

[AndrewT]

I'll take two.

 

[Mr Onion]

I might end up using 4. It all depends on how things sound when I try all the various combinations.

 

[vulejov]

I might end up using 4. It all depends on how things sound when I try all the various combinations.

Wherever you put them will be working better, superior compared to any opamp at both positions.. in the power supply of course leave OP27..

But, again.. single-opamp version works better than phonoclone..

 

[Mr Onion]

Wherever you put them will be working better, superior compared to any opamp at both positions.. in the power supply of course leave OP27..

But, again.. single-opamp version works better than phonoclone..

I'll certainly look into that after I have finished playing with the PC3

 

[mudchute]

Hi all,

I have the standard stereo vsps board wired and ready to go but I'm having a bit of bother understanding the ps wiring. I have 2 12v batteries, how does this work with the v++ com v--?

I wired it V+ +cell1- COM +cell2- V-

I got only smoke!

I also have a 2 pole switch and led to add into the equation.

Any help please!

Ta
Gav

 

[mudchute]

I forgot to say I have the lm7812's bridged like so.

 

[Mr Onion]

I've ordered 5 797's (FIVE I hear you ask. 5 cost less than 4, and 5 only cost £5 more than 2)

I'll have plenty of Op Amps to play with then, and I'll post my findings once I have found them

Typical. I order 5 AD797's in DIP 8 package, and I am sent something in a DIP 16

Got to wait for them to send the correct ones

 

[dimkasta]

I started working on my turntable once more after a year or so.
I am using hammond toroids on my VSPS/PC3 PSU and I never liked how the 160VA transformers vibrated in their aluminum box...
So yesterday I took the plunge and potted their center hole with bee's wax.

Bye bye vibration. Bye bye mid-highs harshness.
Hello crazy stereo imaging and clarity

I really need to work a bit more on the aluminum boxes too... They ring like crazy...

But for now I am reading about opamps...

 

[dimkasta]

I am making a list of opamps to try on my VSPS (for now and then for my PC3).

My current list includes

NE5534P
AD8065
OPA134
AD797
LME4971

Any other opamps I should consider trying?

Please note that I plan to replace C14 and C15 with ceramic 100nF caps to care for the increased bandwidth. Or should I just solder them to the socket? Any other measures I should take?

Thanks
Dim

 

[Mr Onion]

I've ordered 5 797's (FIVE I hear you ask. 5 cost less than 4, and 5 only cost £5 more than 2)

I'll have plenty of Op Amps to play with then, and I'll post my findings once I have found them

OK, here we go. TT is a LP12 with Ittok LVIII and DV XX2 MKII. Gain and load resistors set correctly as per the calculator.

The LME49710 in IC's 2, 3 and 4 gave a noticeable improvement to all areas of the music. Replacing IC 2 with the AD797 was even better. Clearer, lower noise, easier to follow.

Replacing IC 1 was a different matter. Both the LME49710 and AD797 were useless. The sound became thin, muffled, VERY quiet. Almost like a MM cart put in a line input. There is no way I am keeping them in that position. Putting the OPA27 back in IC 1 restored the music.

My recommendation (for what its worth) OPA27 in IC1, AD797 in IC2 and LME49710 in IC3 & 4.

EDIT:- No, I didn't try AD797's in IC3&4 as I didn't have enough to do both channels

 

[vulejov]

Replacing IC 1 was a different matter. Both the LME49710 and AD797 were useless. The sound became thin, muffled, VERY quiet. Almost like a MM cart put in a line input. There is no way I am keeping them in that position. Putting the OPA27 back in IC 1 restored the music..

AD797 and LME49710 at position of the first chip certainly oscillate.. constructor was imagined that Phonoclone work only with impotent opamp.. AD797 will certainly work better and in the first position, try to put a capacitor in parallel with R2, start with 10pF..

 

[vulejov]

EDIT:- No, I didn't try AD797's in IC3&4 as I didn't have enough to do both channels

It is irrelevant which opamp you put in power supply.. for this purpose even OPA27 is enough..