Premier 10 high gain:need help with cartridge loading

[Overhang]

Hello Guys!
I need your advice with cartridge loading. I currently have Premier 10 preamp as my backup and only unit while Premier 18 is on its way for repair. The gain on Premier 10 is so high that I cannot listen to LPs anymore. On one click I get room shaking Sound and I live in apt bldg..I use Grado moving iron with 4 mv output. I was loading it in 47 k ohm setting on Avid Pulsus phono stage with Premier 18. Now that I only have Premier 10,I need the lowest possible output from the phono stage. I was never good with all those parameters like resistance and inductance and most of my life used 4+ mv MC cartridges. I know that lower output can be achieved with switch combinations but am completely confused with dip switches.Please,help with switch combo to produce at least half the output I currently have
I attached my cart specs and photo of dip switches on the underside of the phono stage.

[admin]

So it's too loud, correct?

I would start with the top two double dip switches in the OFF position (MM mode). This should put the lowest gain possible. If the sound is too low (meaning you really have to crack the volume up for listening, go up "MC Low" mode. I see there are two sets of dip switches for the cartridge mode but I'm guessing it's for left and right channels so they should be the same for both sides. So Dip #2 should be ON for "MC low".

Just for clarification, which exact Gardo cartridge are you using?

[AnotherJohnson]

I agree that “all off” is where to start.

I would go MC high next.

HOMC is probably what MC Hi is for, so high output cartridge needs lower gain than LOMC.

If you’re using a 4 mV cartridge, that’s in the MM output range, so I think “all off” will work as well as can be hoped.

You might choose off for the capacitors and 10k for the resistance. But these choice won’t have a huge effect on the gain.

[Overhang]

MM (all switches off) is where I currently stand. Way too loud. MC low is louder than MM. MC High is ear bleeding.

[Overhang]

MC low on this stage means it produces low output,not high gain for low output MC. British design.

[AnotherJohnson]

You’re out of luck then.

Rothwell attenuators might be a bandaid fix while you wait.

An SLOMC is another option… maybe .2 mV.

[Overhang]

The cartridge is Grado Timbre Platinum 3 moving iron. The tt is Technics SL 1210 G.

[AnotherJohnson]

Nothing wrong with either one. The problem is too much gain in the combined phono preamp and line preamp.

[admin]

Looks as if you are not going to be able to remedy the output problem with your current setup. As AJ suggests, a temporary fix would be an attenuator to put in between the TT and phono preamp.

Looking on Grado's website. Looks like the styles come in 3 flavors, high output, low output, and mono. Do you have the high output one? Maybe seeing how much a low output stylus would cost would be a good step. Looks like you don't have to worry about capacitance, so I would just try all the different ones and see which one you like the most.

[AnotherJohnson]

Do you have the correct tubes in the P10?

It specs stock with only 3 dB more gain than the P18. But the P18 max output is quite a bit lower than the P10 if the specs are correct.

[admin]

Do you have the correct tubes in the P10?

It specs stock with only 3 dB more gain than the P18. But the P18 max output is quite a bit lower than the P10 if the specs are correct.

This is a good question. 3 db should not make that much of a difference, maybe an hour turn on the volume knob. Are both the P10 and P18 stock with factory recommended tubes and otherwise unmodified?

[Overhang]

Volume on Premier 18 at 20 on digital readout equal one click on Premier 10.

[AnotherJohnson]

Part of it is that there are 23 discrete volume steps on the P10 and 100 on the P18. But that doesn’t explain it.

[admin]

It doesn't. 3 db is very small and should not be an issue.

BTW- I have no idea why I used the knob analogy above. Still have the images of my older CJ preamps in mind I guess.

[AnotherJohnson]

The literature for the Avid Pulsus phono preamp claims 48 dB of gain for the MM setting.

That SHOULD work great with your 4 mV cartridge sensitivity.

From what you described, it sounds like it did work great with the P18.

The P10, if in spec, ought to work fine too.

I have to wonder about the input attenuation. It may be able to display the proper digits for the levels, but the visual is usually not in the audio circuit and I can’t help but wonder if there is a short causing “one click” to actually be equivalent to many more.

I’ve looked up the stock 6GK5 tubes. They are single miniature triodes without s lot of equivalents that might have been chosen to buggar things up by a tube roller. If they’re 6GK5s, the problem is probably not the tubes. I am suspicious of that input attenuator ladder.

Is the loud volume coming from both channels symmetrically?

What’s Roberto think? Or others?

[Overhang]

It is the initial first click on the volume control that is loud. After that the volume increases gracefully.
I am using NOS GE 6GK5 tubes that I bought 20 years ago on EBay for $60 a case. The best sounding tubes for my setup.

[AnotherJohnson]

For whatever reason, as you’ve noted, just too much gain for that low end of the ladder.

You’ll probably have your P18 back soon, so maybe it’s just not worth much more trouble shooting. When you had the earlier mods done to the P10, the gain may have been matched to that single source. I’d guess that at most four resistors would change it back, but it would not be worth it to me.

[AnotherJohnson]

It doesn't. 3 db is very small and should not be an issue.

In a stock P10, volume clicks are each in increments of about 4% of full output. In a stock P18, volume clicks are each in increments of about 1% of full output.

So you would expect that the first click would be noticeably louder on the P10 compared to the P18. It’s a greater percentage of a greater full output. Maybe that is enough to explain it.

ARC sent me parts (resistors, solder, instructions and pictures) for free when I was interested in possibly reducing the gain on my LS28. I don’t think CJ would do the same, except perhaps for Roberto. But I do think that CJ would do such a modification for a customer at their shop and for their normal costs.

I also know from first hand experience that for mods that are requested through dealers, CJ have historically given the dealer a cut. So … if mods are requested/arranged through your dealer, there may be some room for negotiation if it’s a dealer with whom you’ve already developed a good relationship.

[lowpoweraudio]

I wouldn't use/add vol pots in line between the phono stage and the preamp as you'll create all kinds of other problems. Simply replacing the output resistors in the PTen which are 47R with perhaps 200R. Perhaps someone can calculate a better value to reduce the output by 3-6db. I would use a good quality resistor like a 2w Audio Note Tantalum. It will cost you $50-60 for the two resistors. This is super super easy replacement. I replaced/upgraded several of the resistors my my P10 with outstanding results. The bulk film Vishays CJ uses are OK but not all that to write home about. They must have bought a lifetime supply of these to be using them over and over in designs for the last 30 years. I'll post some pics and youtube links from my CJ Premier Ten project.
***But first, your Grado is High-output MI/MM Cart. Thus set your phono preamp loading to MM only and 47k loading. The Grado is not sensitive to capacitance but I would set it a 100pf.