I had actually considered step up transformers. When you start thinking about the different transformers you then get into shielding, turns ratio's, and gain. Then you start reading all about different transformers like the Altec/Peerless 4722's, 15095's, the 3A55's, the MC2, and the Altec 4665's out of this bunch the only ones I would consider right off the bat would be the 4722's or the 4665's if I could find a matched pair of 4665's. There is a nice paper I downloaded from 404 Not Found back in 2011.
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I'd strongly consider Lundahl units, available from K&K Audio. Their model LL9226 is excellent for MC/LoMC step up. I use these in my builds. Also, you don't have to worry about 'matched' units, these are fine and super high quality.
K&K Audio also sell a ready to go unit in a metal case etc, and it can be configured for different ratios.
K&K Audio also sell a ready to go unit in a metal case etc, and it can be configured for different ratios.
I went to their site but there was no information that I found on the transformer shielding. The Altec 4722's I know would work.
if you have a look at the data sheet of the LL9226, it is built in an MU metal casing and has pins coming from the core and casing which are usually connected to ground, so yes, they are fully shielded!
Trust me, I would not use it otherwise!!
They also have many different units which can be used as a SUT, some cost way more due to the materials used, so you do have many different choices.
So it comes down to what you are prepared to spend. From a quality point though, Lundahl, in my opinion, are one the best. I exclusively use Lundahl audio transformers and OPT's in most of my custom builds.
Trust me, I would not use it otherwise!!
They also have many different units which can be used as a SUT, some cost way more due to the materials used, so you do have many different choices.
So it comes down to what you are prepared to spend. From a quality point though, Lundahl, in my opinion, are one the best. I exclusively use Lundahl audio transformers and OPT's in most of my custom builds.
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R8 R9 in the original plan.
The loss here is only a few dB and necessary to get the 2kHz corner.
Of course the network must be recalculated or changed ... but can be done
1,45 division ratio ( for 1V you get 0,6875V ) for all signal is pretty significant , and most designs are not made in this way . The goal is to attenuate only what RIAA curve needs , not all frequencies . After all why to amplify the sigbal only to lose it in a passive divider ...
1,45 division ratio ( for 1V you get 0,6875V ) for all signal is pretty significant , and most designs are not made in this way . The goal is to attenuate only what RIAA curve needs , not all frequencies . After all why to amplify the sigbal only to lose it in a passive divider ...
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You can certainly input a 1kHz sine of about 10mV, and see the output sine at the source switch
with a high impedance probe. Use an input attenuator at the phono input, series 10k and shunt 100R,
for attenuating a 1V signal generator sine to 10mV accurately. This will give the midband phono gain.
Don't attempt to alter the RIAA network, this depends on the tubes as well as the Rs and Cs.
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