[mhconley]

My vinyl playback system is a Grado Reference Sonata 2 (4.8mV output) through a Cambridge Audio Duo phono preamp into a YS-Audio Audio Experience balanced A2 preamplifier into a biamplified pair of Von Schweikert VR-4 Gen III HSE speakers (88dB sensitivity) with 17W 300b PSET monoblocks on the top and 1000W ICEpower monoblocks on the bottom. I use a relay based passive pre to balance the top and bottom. When playing vinyl through this setup I have to pretty much peg the preamp to get acceptable volume.

I don’t have this problem playing digital through my Topping DX7s DAC into the same preamp. I also did not have this problem with my old PS Audio GCPH phono preamplifier. Both digital and the old phono pre can hit uncomfortably loud levels if I crank up the volume.

One difference is the DAC and PS Audio phono preamp use balanced XLR connections and the Cambridge Audio Duo uses single ended RCA connectors.

I am wondering if a 1:2 step up transformer would help provide an acceptable volume level. I’m looking at this one: https://www.amazon.com/dp/B07DM16M7H/.

Any advice?

Thanks,
Martin

[S Clark]

This just doesn't make sense.     4.8 mV is way more than enough to match with that Cambridge.  I've run an ADC xlm mkii with similar output through a Cambridge to a Dodd pre with no issues at all.  Do you have another phono stage or even an old receiver that you could swap out? 

[mhconley]

I had a Lounge Audio LCR MKIII and a Cambridge Audio Solo that both exhibited the same lack of volume as the Duo.

Martin

[S Clark]

  ??? Nothing in your systems listed indicates an issue.  You have way more than enough power, speakers are easy to drive... something is off here. 
15 watts should be enough to drive you from the room.
Is this in your B&O/von Schweikert room?? If so, have you hooked it up to your AV system?

[SET Man]

Hey!

    Your Grado should have enough V to drive any MM phono pre. It seem like your phono pre just don't have enough output for your pre and amp combo. Your digital front end likely have the standard of 2V to your pre. I'm curious of what your phono pre spec is when is come to output V to pre.

   By the way, I have the opposite of your problem. My MM phono pre section in my pre combine it's line stage and my amp is a bit too much gain for me overall even with 2.5mV high output MC cart. A bit annoying because I'm using 24 stepped attenuators volume control

Buddy

[mhconley]

There is a review of the Cambridge Audio Duo on AudioScienceReview (https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-cambridge-audio-duo-phono-preamp.6901/) that states it needs 11.3mV of input to hit 1V output. That tells me that it’ll output only 0.4V with my 4.8mV cartridge. That’s 1/5 the output of the Topping DAC. Things are beginning to make sense.

The 1:2 transformer should get me to 0.8V. Is my reasoning correct?

Martin

[mhconley]

I verified the Duo only has 39dB of gain on the MM input. That is 0.42V from 4.8mV of input.

Instead of adding a 1:2 SUT to my setup I’m thinking of replacing the Duo with a Pro-Ject Phono Box RS that gives me balanced outputs and 46dB if gain for 0.96V of output.

Martin

[sunnydaze]

I have the exact same line stage.   I know what your problem is.  On the YS all inputs and outputs are both XLR and SE, and the gain profiles are different depending on which configuration you use.

The YS input to output gain specs are:

RCA to RCA:     4 db
RCA to XLR:    20 db
XLR to RCA:    14 db
XLR to XLR:     20 db

I assume you are using the YS SE outputs?
If so, you have very little gain when using your SE sources, and it's why you hear weak volume vs your XLR sources.  Clearly, any setup that uses XLR anywhere on the YS (either in or out) gives you either 10 or 16 db more gain.

When using all SE throughout, the problem can be alleviated somewhat by using amps with sensitive inputs, and/or high efficiency speakers.

Good luck sorting out your situation.

~John

[mhconley]

Eureka!

The phono preamp uses uses SE and the DAC uses XLR. As does the PS Audio GCPH and Pro-Ject Phono Box RS.

My 17W PSETs are on the SE outputs while my ICEpower amps are on the XLR outputs. This also explains why I have to adjust the passive pre I have on the ICEpower amps when switching between analog and digital.

I just bought a Little Bear MC3 3-in 3-out XLR/RCA converter selector splitter box. I’m going to try some experiments with it today.

Thanks!
Martin

[sunnydaze]

You're welcome.   

I was able to figure it out in my rig because I too was having vast volume differences  when using the various YS ins and outs.  Lots of head scratching....didn't make sense...so I did some digging and I uncovered the specs above.  Then everything became crystal clear.

[mhconley]

I tried the MC3 and it had no effect. Thinking about it, it could not. It’s a passive device and cannot produce a balanced signal from the SE input. Only 1 pin of the XLRs two signal pins will contain a signal.

I’m going to buy a Pro-Ject Phono Box RS. It’s too bad the PS Audio GCPH added so many harmonics. It was a great phono pre in theory but junk in practice. When playing a 1kHz tone from my Analogue Productions Test LP through it I could easily hear 2, 3, 4 and even 5kHz tones. A simple dB meter on my phone verified what I was hearing. No telling how much it was muddying up my vinyl playback. Hopefully the Phono Box RS is well engineered.

Martin

[sunnydaze]

Here's a thought....

Maybe just use the phono stage that you like with SE outputs and run it into the YS XLR inputs using a female RCA to male XLR adapter, like this:

https://www.parts-express.com/xlr-male-to-rca-female-adapter--240-438

Could be a simple, cheap and elegant solution?   

In the past I have used these cheap adapters and TBH could hear no detriment to the SQ even when compared to audiophile approved pricey snake oil ones that I borrowed from a friend.  YMMV.

[mhconley]

I think those adapters would behave the same as the MC3. Only one of the signal pins would have a signal on it. I believe the reason the XLR to RCA path has 14dB if gain vs the 4dB on the RCA to RCA path is that the XLR has two input signals vs one on the RCA. The MC3 and those adapters simply pass the single RCA signal into one pin of the XLR. I believe you need a truly balanced signal to get the full 14dB of gain on the XLR to RCA path.

Thanks,
Martin

[sunnydaze]

Not sure about that....I'm surely not very technical.  And I don't really follow exactly how you connected things with the Little Bear, or what it's doing.

But my understanding is.....and take this with a large grain of salt.....that an extra pair of tubes is used with the YS XLR inputs, and that's where the extra gain comes from. Only 2 pair are used with RCA inputs, while the full 3 pair are used with XLR inputs.  But I could be wrong.   

(On 2nd thought...maybe it's the XLR outputs that use the xtra tube pair?      )

Anyways, it's easy and cheap enough to find out.  Were I in your shoes, for less than 10 bux I'd give those adaptors a go.  Plus, it's always good to have something like this in the audio tool box.

[sunnydaze]

Edit:   giving it more thought, and looking at the gain specs above, it stands to reason that using the XLR outputs is the config that uses the xtra tube pair and therefore gives more gain.  My logic is that XLR outs yield the same 20 db regardless of the inputs used, therefore the outputs are the relevant factor in bumping up the gain so much..

Now, XLR input with RCA outs also gives slightly higher gain, but I believe that's the result of the typically stronger XLR signal, and I don't believe is caused by xtra tubes used at the XLR inputs.

I'm pretty sure this is how it works, and if so, you are correct that the adaptors will not boost the gain.

[mhconley]

XLR inputs have double the signal strength of SE when they are fed by a truly balanced source. Pin 1 is ground, pin 2 is the + signal and pin 3 is the - signal. The signal is balanced between pins 2 and 3 hence the name. RCA or SE has the signal on the center pin and ground on the shield.

For example: while an SE connection is 1V (1V - ground = 1V) and truly balanced signal will be 2V (1V - -1V = 2V)

When the MC3 or those adapters convert an SE signal to XLR they put the signal on pin 2 and connect pin 3 to ground. A truly balanced connection will have a signal on pin 2 and the opposite signal on pin 3. So a balanced XLR provides double the signal of SE or an XLR converted to SE.

In any case I have a Pro-Ject Phono Box RS en route.

Thanks for the assistance in figuring this out.

Martin

[sunnydaze]

YW

Good luck on your endeavors.  That Pro-ject surely is super adjustable.  I like that.   

Different for them as their stuff is usually tubed.  Hope it sounds good.  Keep us posted on how it works out, I'm curious.

[mhconley]

I received the Pro-Ject Phono Box RS today and my volume issue has been resolved. I’m using the 46dB gain setting on the XLR outputs. My vinyl setup is once again playing at the same volume levels as my digital setup.

So the problem was the gain through the Audio Experience A2 RCA inputs. An extra 7dB from the phono preamp doesn’t hurt either.

The new Grado Reference Sonata 2 sounds great. I’m once again happily spinning vinyl.

Martin

[sunnydaze]

That's great,  congrats.     

I was quite confident that going XLR into the YS would fix things for ya.  It's simply the gain profile of the line stage.

My MM phono stages have 40 db of gain and I run them single ended into the YS .  It's definitely not as loud as my other digital sources but things are fine for me as I don't listen very loud at all.  The 2 HO carts I use are Cartridge Man Music Maker 3 and SoundSmith Zephyr 3.  The Music Maker output at 4.0 is similar to your Grado but the Zephyr is only 2.8.

I also use a couple of LO MC carts with the YS single ended inputs.  Total phono stage gain is about 60 db and cart outputs are in the .28 to .40 mV range.

[andyr]

It’s too bad the PS Audio GCPH added so many harmonics. It was a great phono pre in theory but junk in practice. When playing a 1kHz tone from my Analogue Productions Test LP through it I could easily hear 2, 3, 4 and even 5kHz tones. A simple dB meter on my phone verified what I was hearing. No telling how much it was muddying up my vinyl playback.

Martin

That is indeed sad, Martin (that the PS Audio GCPH is so bad, in practice!  ).  How is it possible that a commercial product can add so many harmonics - at a level that can be picked up by phone's dB meter!!??

BTW, in terms of your original Qu "I am wondering if a 1:2 step up transformer would help" ... yes it would double the output of your cart - but it would also make the load seen by your cart 1/4 of the default 47K ohms.  Which would not make it sound very good!   
(The equation is: load with a SUT = MM phono stage load (typically 47K) / SUT coil ratio squared.)

Andy