School me on db gain for cartridge

[Mopardave]

Im a bit new in the vinyl camp. I have been using a VPI prime 21 with a Ortofon Black LVB 250 and MapleTree phono(3c) pre into a MapleTree line pre(2crm). The 2crm has 3 inputs, each having a higher level of gain. 10db,15db and 20db and to my ear the 20db gain sounds the best. My question is how do you determine the best level of gain and does it become a situation of diminishing returns at some higher level? The phono 3c has 30db gain output. My LVB 250 requires 42db gain, tried 45 then 50 and 50db gain on this cartridge was wow, just wow what a nice improvement. Does it get better with more?
I will be stepping up the cartridge soon to a MC. Probably the AT art9xi or xa and need to know what im doing. Thanks

 

[shelly_d]

Gain is simply the amount of amplification an amplifier does to a signal. Typically, with high quality devices, the amounts of noise and distortion an amplifier adds to the signal varies with the amount of gain, but usually not enough to be audible, sometimes not enough to even measure. Use the settings that sound good to you and don't worry about what is best.

What you want to know, is that the gain of one device adds to the gain of the next device, so the 30dB of the 3c adds to the 10, 15, and 20 dB of the 2c to give you 40, 45 or 50 dB of overall gain. As long as you don't feed to strong a signal into the next stage of the chain to cause distortion, and it continues to sound good to you, you can play with the inputs and volume control to your hearts content.

Shelly_D

 

[DesertRatt]

Since the 1960s or so, there was a "rule of thumb" standard for gain in a MM phone stage - - 42dB. It assumes the line stage to have 20dB, and all that assume an amplifier with a 2V sensitivity. Again, it's not a rule or a standard - just a convention followed by many.

 

[Buck Rogers]

Oh Baby~~!

Your going to like a Low Output Moving Coil cartridge.

Going from a Shure V-15 III to a High output Sumiko Blue Point special was a revelation.

I thought that was the end, But moving to a LOMC was another revelation.

Lastly was the LOMC Step up transformer.

Not such a big deal until I got great transformers (Peerless 4722, 4665)... Another HUGE revelation.

My system has come light years with these upgrades.

As for gain, I use transformers in lowest step up configuration then add a loading potentiometer across the secondary.

With this I am able to adjust preamp gain much lower and still get amazing sound.

One of my favorite SUT's is the Shure M67 microphone transformer at about 60$ a pair.

There is a "Synergy" between a Moving Coil and a transformer,

As they are both "Transformers" one just has a mobile primary.

 

[mrwood200]

Im a bit new in the vinyl camp. I have been using a VPI prime 21 with a Ortofon Black LVB 250 and MapleTree phono(3c) pre into a MapleTree line pre(2crm). The 2crm has 3 inputs, each having a higher level of gain. 10db,15db and 20db and to my ear the 20db gain sounds the best. My question is how do you determine the best level of gain and does it become a situation of diminishing returns at some higher level? The phono 3c has 30db gain output. My LVB 250 requires 42db gain, tried 45 then 50 and 50db gain on this cartridge was wow, just wow what a nice improvement. Does it get better with more?

You want enough phono gain to power your line stage to make the best sound!
At a minimum, you need enough gain to meet the preamp's input sensitivity. I don't know what the sensitivity is for the 2crm, but 150-500mV is a common range
LVB = 5mV + 40dB = 500mV. You should be able to power your preamp w/minimal gain from phono.

Now, you may want more gain if your system sound better with more phono gain; maybe your preamp needs a stronger signal, or your system sound better when your amp is not working as hard. Maybe (probably?) it sounds better because it is louder; we can be fooled with more volume! Most 5mV cartridge systems will be satisfied with 40-45 dB gain; 50dB is unusual.

I will be stepping up the cartridge soon to a MC. Probably the AT art9xi or xa and need to know what im doing. Thanks

Good idea to see what your system can do with a MC! And you have some fine equipment!
AND I am a MapleTree fan, but 30dB phono (w/10/15/20 dB from pre) is odd. Depending on what MC you choose, 50dB may not be enough gain.
I think we should run @40dB and join @Buck Rogers w/an appropriate SUT for your new cartridge!

 

[Buck Rogers]

I'm using the Audio Technica AT-OC9 XML and am delighted!

With a Nude stylus and Boron cantilever it is the Ferrari of cartridges.

I imagine the ART line would be amazing.

But at 550$ if I ding the cantilever it's not like a 1,000$ loss.

I also prefer manufacturers that historically make a lot of cartridges.

Economy of scale... I tried a 300$ AT LOMC cartridge and was Blown away! Amazing quality and sound...

The future is Shiny~~!

Last item. I have SUT's that run from 5:1 to 50:1 ratios. Volume wise there is only a small difference?

But in every case the lower the ratio the better the sound!

EDIT: It's not so much crazy better, It's like more personal and close up.

Most microphone transformers are 300 ohms Z, Which presents a very "Light" load to a LOMC cart.

Light turns out to be very good almost perfect! Load the secondary down to make the Cartridge happy~!~?

Sorry for rant. Cartridge loading turns out to be another favorite Wheel House for me...

 

[mrwood200]

I purchased this maple tree line pre back in 2003. 2A SE, but has same specs as the new one.

And yours is wired for 10/15/20 dB for L1/L2/L3?
I think I am going to revise my 50dB comment ...............

In general, we want 40dB phono gain for our 5mV MM cartridge so our preamp can take it the rest of the way (+10-25dB) to our power amp.
You only have 30dB phono, so we need the 20dB preamp: 10 for the phono makeup + 10 for preamp.................

 

[mrwood200]

What do you suggest for a sut?

What is our budget?!? Just for the 1x cartridge? What is the turntable??

Let's start with our forum sponsor & OEM @rothwellaudio - good equipment & excellent primer . I appreciated their Denon example calcs as well.
To size our SUT, I have taken away from this expert & others (paraphrasing) 'get the gain right, keep turn ratio low, then double check resistance loading'.
We want to bump up the MC cartridge to mirror MM level to work with the rest of our system. So we are at .5mV & need gain to get to ~5mV.
You can do the math or ask Google: .5 + 20dB = 5mV (same as LVB!)

SUT can have specs w/dB gain or turn ratio. In general, a 1:10 SUT offers a 10x voltage/20dB gain. 1:10 SUT is a classic w/numerous versions available.
(To finish with sizing: 1:10 is a low ratio. Resistance loading is fine (should be ~470 >>12 ohms))

 

[Buck Rogers]

Pretty light on specs...

But, The 150 ohm setting is encouraging... Price is not excessive.

SUT's are another piece of the puzzle that can greatly exceed the resolution of your system.

Edit: I'm still in the "Old School" transformer camp...

 

[mrwood200]

Looking at the Pro-Ject MC S3 sut. Budget for the cart is about $1500. My TT VPI Prime 21.

$1500 cart & SUT? Google says AT art9xi + MC S3 >$1500
Either way, we are going to need a bigger boat.

Pretty light on specs...

Agreed. and don't like.

But, The 150 ohm setting is encouraging...

......or is it?
ProJect makes fine stuff. I am sure this is fine & would work fine.
I don't think this is the SUT for our OP's fine system. This is their entry-level SUT, 1:16 in-house transformers, with __________ to offer 2x gain settings.
This is thinner ice for me, but, my understanding, SUTs can offer gain options by offering access to other windings of the same transformer w/different turn ratios. That could be what they are doing, but ? A 1:16 offer 24.1dB gain, so that is the 24 setting; ~1:11 offers 21dB?
And no info on cartridge load......a 1:16 offers ~184 ohms, but some add some bits to offer X loading. I don't know if the button on back changes gain & load?
I think Google AI is guessing, but when asked "does MC Step Up Box S3 use a zobel network or resistive loading?", it answers 'The Pro-Ject MC Step Up Box S3 uses resistive loading via a manual impedance matching switch rather than an internal Zobel network.' Add it up, meh.

Again, lot of options out there. YMMV. I can offer 2x that I own & use:

Denon AU-S1	1:13, 278 ohms ‘Compatible with 3 ~ 40 Ω cartridges’
Denon AU-340	2x TT inputs, Tamura transformers with 3x options: 3 Ω (1:33, 43 Ω) 40 Ω (1:10, 470 Ω) bypass

 

[flavio81]

Im a bit new in the vinyl camp. I have been using a VPI prime 21 with a Ortofon Black LVB 250 and MapleTree phono(3c) pre into a MapleTree line pre(2crm). The 2crm has 3 inputs, each having a higher level of gain. 10db,15db and 20db and to my ear the 20db gain sounds the best. My question is how do you determine the best level of gain

When you are using an amplifier (like your pre-amplifier), the selection of gain is a tradeoff:

too much gain, you get increased noise floor, and if the cartridge signal is too high, you get distortion.

too little gain, you need to increase the volume dial (on your amp) too much.

When you are using a transformer as a gain device, better check out the Rothwell Audio primer cited above:

https://rothwellaudioproducts.co.uk/html/mc_step-up_transformers_explai.html

 

[muovimies]

SUTs don't really go bad so for a frugal buyer there are many vintage SUTs around from the likes of Denon, Fidelity-Research, Entré and bunch of others that provide good value and prices generally seem to be going up, not down so you should get your money back down the line if you decide to sell.

 

[gadget73]

just something to point out with an honest to goodness SUT, they don't actually have any particular load impedance in and of themselves. Its a function of the ratio and what they work into.

The impedance is a square of the ratio. If we're talking a 1:5 for example, the impedance ratio is 15x5) or 1:25
What that means, if you're working into a typical 47,000 (47K) load, what the cartridge sees for a load is 47000 / 25 or 1880 ohms.

If 1:5 is the correct voltage step-up and you need something other than 1.88K for a load, you can simply parallel resistors across the primary. If the desired load is say 200 ohms, the formula is 1/200 - 1/1880 = 1/new resistor or 223.8 ohms. Alter that for reasonable availability, there is probably a 223 or a 224 ohm resistor out there but there are absolutely loads of 220 ohm.

thats probably on the low side, I'd figure 1:10 being a little more typical. An 0.3mV cartridge through a 1:10 SUT will give 3mV, and thats in the zone for a mag phono stage. Impedance ratio on that is 1:100 (10x10) so that 47K load appears as 470 ohms to the cartridge.

can load it on the secondary too, I honestly have no idea if there is an advantage. The parallel resistance thing is what it is, but its across 47K, and you have to factor in the impedance ratio to get the load presented to the cartridge.

None of this applies if we're talking a head amp with active gain. The input load is whatever it is, and the load downstream and the gain setting has no effect on it.

 

[Buck Rogers]

Been using Variable Loading and pure silver wire in my SUT's for over 20 years, It's a great way to go.

Also, All those used SUT's on ebay in the 200 to 500$ range sound Excellent! I've owned many of them and am impressed with their performance.

No need to spend big bucks.

 

[mrwood200]

you guys are way over my head with all this info. Wasnt looking to spend a bunch on a sut. Thought maybe $2000 for cart and sut and the pro-ject looked to fit the ticket.

No worries - you are fine w/LVB + your future plan is AOK. There can be some math & science, but it gets easier after your 6th SUT .........
$1.5K - $2K for cart & SUT is a great budget; just got to match the pieces.
You picked a v.good cartridge + the SUT should work fine......I just think there is a better value/performance SUT to match the quality of the rest of your system. I want to know about 'who made transformers', parts, specs, etc. I like to see naked pictures, AND photos of inside in case ......

fyi - misc thoughts
- AU-305 on auction site for v.good price
- What are your plans for the LVB? Crazy idea - run it till it drops, contact Ortofon about trade-in, see what they offer, get MC X40 + ortofon SUT for great deal (maybe...)

 

[shelly_d]

I got a Denon 300 MC cartridge with a Denon SUT to use with it some years ago. I had the opportunity to try it with the transformer, a phono stage made for a low output MC cartridge and the MM stage of my amp (MA6200). They all all sounded the same to me once I equalized the volume when using just the MM stage in my amp. Understand that with just the amp's preamp section in circuit the max volume was very restricted but within the listening levels it was capable of, it sounded just fine.

Having said all that, be aware that I am in my 70's with the attendant hf hearing loss that comes with that age.

You might want to try the MC initially without the transformer and set up your system to use the max gain and see if you are happy. If so, great, if not, then look for either a MC gain stage, an MC transformer, or MC preamp.

Shelly_D