I'm switching over to a MC cartridge and was wondering if I can easily increase the gain of my preamp instead of using SUTs to increase the output of the MC cart.
There won't be any extra gain available in commercial phono preamps, unless it was part
of the design in the first place. Hence the market for step-up transformers and pre-preamps.
And generally for a given specific circuit, the higher the gain, the higher the noise.
of the design in the first place. Hence the market for step-up transformers and pre-preamps.
And generally for a given specific circuit, the higher the gain, the higher the noise.
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What LOMC cartridge is being acquired? Which MM level phono preamp is in use?
Most, but definitely not all, LOMC carts. are fine in combination with 1:10 SUTs. Some MC carts. are ultra-low O/P and may need as much as a 1:20 step up ratio.
Given the comparative proximity of NM to CA, I suggest the OP look into the offerings of CineMag and Jensen.
Most, but definitely not all, LOMC carts. are fine in combination with 1:10 SUTs. Some MC carts. are ultra-low O/P and may need as much as a 1:20 step up ratio.
Given the comparative proximity of NM to CA, I suggest the OP look into the offerings of CineMag and Jensen.
You can add extra amplification stage, but it is not that simple. Even selecting low noise tubes and paralleling them, you won't get the same S/N ratio as with good well-shielded step-up transformer.
The new cart it the Denon DL-110. My pre amp (not the phono pre) is pete millett's low mu preamp and I can increase or decrease the gain just by changing the output tube. That's what got me thinking I might be able to do something simple to increase the gain of my phonopre.
It is the Hagerman octal Cornet by the way
It is the Hagerman octal Cornet by the way
The Denon DL-110 is a high O/P moving coil cartridge. It is not used with a 20 dB. step up device. Instead, it gets connected exactly like a MM cartridge. However, the O/P voltage of the DL-110 is only approx. 1/3 that of many MM cartridges. Therefore, additional gain someplace in the playback chain is likely necessary.
The Noval "Cornet" manual is here. Substitute 6SL7s for the 12AX7s and a 6SN7 for the 12AU7 and you have an Octal variant. You can try to get increased net gain by replacing R15 (130 Kohms) with a 950 μA. CCS of good quality.
Or just use sand, which from my experience worked the best with most Low Output MC for pre-pre.
That was until I finally ditched all the MC stuff and got back to MM. 😎
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Ok, the DL-110 puts out 1.6mV so is a quite High Output MC. Did you get it already? Can I convince you to maybe go for the DL-103r instead? Or an Ortofon 2M perhaps? Depends on the tonearm of course.. oh well, this is not the place to discuss cartridges (sorry).
It's a semi-budget MC cart. I would do either of these two things if you have it and are really finding the level too low:
1. Rig up a j-fet on the input of the MM stage to boost the signal only like 2x. Nobody will hear the difference. It will not add any noise.
2. Sell the DL-110 and get a nice MM cartridge.
Ian
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The "gotcha" is the not so high (1.6 mV.) HOMC Denon DL-110 acquired by the OP. That cart. is (IMO) neither fish nor fowl.
At 3.3 mV. under "standard" conditions, a HOMC from Ortofon would probably be OK.
A Steve Eddy idea is a potential solution to the DL-110 conundrum. Use a low noise JFET source follower to present an ideal load to the cartridge. The FET's O/P would be used to drive this CineMag microphone transformer. That trafo's secondary can be loaded ideally and the voltage fed to the Octal Cornet phono preamp would be satisfactory.
At 3.3 mV. under "standard" conditions, a HOMC from Ortofon would probably be OK.
A Steve Eddy idea is a potential solution to the DL-110 conundrum. Use a low noise JFET source follower to present an ideal load to the cartridge. The FET's O/P would be used to drive this CineMag microphone transformer. That trafo's secondary can be loaded ideally and the voltage fed to the Octal Cornet phono preamp would be satisfactory.
The idea of a source follower driving a step-up transformer is an excellent suggestion. I forgot about it...
But even the CineMag is something like $75 each. Not sure what the OP's budget for this is.
I never used CineMag, but I did use the 1:5 Jensen JT-13K7 (with a couple of different carts) and it was very good. Maybe the OP can get lucky and find some old stock transformers.
Ian
But even the CineMag is something like $75 each. Not sure what the OP's budget for this is.
I never used CineMag, but I did use the 1:5 Jensen JT-13K7 (with a couple of different carts) and it was very good. Maybe the OP can get lucky and find some old stock transformers.
Ian
At such low signal level and impedance, bite the bullet and build an SS preamp, it will work better and have less noise than any transformerless tube one.
Ok, I had to read through all the posts a couple time. A good friend of mine gave me the Denon after using it for a week on his TT and didn't like it.
I built my phono pre and my preamp and TT and tonearm so I don't want to get rid of any of them.
The problem with going to any other cart is I don't know the compliance.
So many variables it's making my head hurt. I'll mount the Denon and see how it sounds then go from there.
I built my phono pre and my preamp and TT and tonearm so I don't want to get rid of any of them.
The problem with going to any other cart is I don't know the compliance.
So many variables it's making my head hurt. I'll mount the Denon and see how it sounds then go from there.
I'll guess that friend was impacted by the 1.6 mV. O/P. If you can't get decent performance out of the DL-110, have your friend read this thread.