AP20 vinyl trouble

[MK1LN4E:)]

Upon being very fortunate to demo a friends ap20 I have found it doesn't seem to work well with my project debut phono stage in the sense that I have to crank up the volume to at least half way to get an adequate volume. I mean I say my phono stage there could be tt or cartridge issues too. Any input would be much appreciated. Just to add With CDs there is no issues it drives my speakers very easily.

[Dr Bunsen Honeydew]

You need a different phono stage with more gain. OR if the gain can be increased on that phono stage.

[MK1LN4E:)]

There is no gain controls, it's as basic as it comes to be fair. To which i'am aware of its capabilities, it was such a shock as my cyrus isn't affected to such a degree as this.

[Dr Bunsen Honeydew]

It should be no differet, gain is voltage it has the same for both amps. If this was correct then the cyrus would be louder on CD.

As I say gain is not a volume control in this case, it is the phono stage is not producing enough voltage so a couple of resistors needs changing in the phono unit to increase the gain (if it has it in the first place).

[_D_S_J_R_]

Which Cyrus? Old ones had a log law, as many other amps do, which means 'all or nothing' in the first third of rotation. Not a lot happens thereafter.

Volume controls are just that, a means of matching the volume level. Many sources, from phono stages, to old tuners and tape decks, to the significantly higher output of all CD players, will all vary to a degree and for example, on the AP20 I'm using, the PC's soundcard has a lower output than my CD source and both again, are slightly different to the phono stage I'm using. THAT's what a volume control is for - see what I'm getting at guv'nor? Half way up is perfect.

[MK1LN4E:)]

Understood cheers doc. I don't want to damage the amp by running it at higher volumes to compensate.
Just to go onto another subject, when u design your phono stages to say a particular cartridge spec would that hinder someone upgrading to another cartridge would they have to get the phono reconfigured or is there not a great deal of difference between them.

[Shevans]

Long time ago I had a pro-ject preamp and had similar gain issues, bough a more expensive one with internal jumpers that allowed you to set the gain level.

[MK1LN4E:)]

Which Cyrus? Old ones had a log law, as many other amps do, which means 'all or nothing' in the first third of rotation. Not a lot happens thereafter.

Volume controls are just that, a means of matching the volume level. Many sources, from phono stages, to old tuners and tape decks, to the significantly higher output of all CD players, will all vary to a degree and for example, on the AP20 I'm using, the PC's soundcard has a lower output than my CD source and both again, are slightly different to the phono stage I'm using. THAT's what a volume control is for - see what I'm getting at guv'nor? Half way up is perfect.

Yeah my volume on the Cyrus is very gradual you have to turn it a lot, if you like. But as you say when you get to twelve o clock not a great deal louder. Mine is a digital readout now on the display not like my old 7 which had LEDs.
Now there is a difference on my cyrus between cd and phono and DAB but I don't seem to have to push the amp as much as I had to push the AP20 whether it's because the Cyrus has a louder spec then the ap20 I don't know. Considering how loud it is with CDs it just was a considerable shock that's all. I have the dial turned down next to nothing on the ap20 with CDs and at twelve for vinyl same noise if you like. My cyrus not so bigger gap, hey ho.

[Dr Bunsen Honeydew]

Understood cheers doc. I don't want to damage the amp by running it at higher volumes to compensate.

Sorry mate you don't understand, you are not running the amp harder - voltage is voltage it has nothing to do with position on volume control.

For example 1v in and the amp will clip at two thirds of volume control, 500mv in and you will have to go full out on volume control to get near to clip (used as examples not factual figures). The amp doesn't *know* the difference.

Volume controls are different on different amps.

[Dr Bunsen Honeydew]

Just to go onto another subject, when u design your phono stages to say a particular cartridge spec would that hinder someone upgrading to another cartridge would they have to get the phono reconfigured or is there not a great deal of difference between them.

There are some odd sods, but mosts MC are alike and most MM are alike enough not to bother making changes.