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Phono stage upgrade

Nagraboy said:
Seems to be totally different. Not LCR but a combo of NF and CR type EQ. HiFi News reviewed it recently and were impressed. I’d love to try one.

Unfortunately my brand new Rega P8 is out of action after only one day of use due to the Apheta 2 now mistracking. Dealer advised increasing VTF but that made it worse if anything. Literally everything I buy is F+*£*& up in some way :sad face:
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Oh no :(
 
Tarzan said:
Had a PM suggesting trying a tricked up EAR834P (poncy valves, iec inlet, phono sockets and changing a couple of internal bits) any thoughts chaps?
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I have a Chinese copy and am more than happy with it. However I can’t really recommend going down the Chinese route as I had to send it to @Arkless Electronics to get a persistent hum removed - he also upgraded some of the components. However, now that it’s been fettled I really, really, like it - and am on the waiting list for a Jez designed MC/MM step up amplifier.

EAR have recently announced the replacement for the 834P.
 
You might want to consider one of these:

Convergence-1.jpeg


This was part of an audio system demonstrated at T.H.E Show, Newport Beach, California a couple of months ago and received some great write-ups by the top US magazines... Some can be found here.

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Prices start at £1000
 
Valab LCR. I kid you not it is phenomenal, and not just for the money, ignore the price tag - it performs with the best phono stages I've heard, seriously.
 
With any LCR phono stage, I would want to see an accurate RIAA plot to verify how accurate the EQ is on each individual phono stage. Winding accurate inductors is both time consuming and very expensive as there is a lot of waste. Many have to be discarded if they don't meet the close tolerances. My bet is that many out of tolerance inductors are still used in production due to the costs involved in discarding them. I've also had first-hand experience of this.
Performance-wise it is very difficult, in fact, it is almost impossible to properly drive a 600 ohm EQ network with a valve/tube circuit, which is why many LCR networks have greater impedances then 600ohms. I have seen 10K networks used but these are not supposed to sound as good as the lower impedance ones. It is much better to use a solid-state circuit to drive a 600ohm LCR network.
 
Aurorasound get their eq inductors from Lundahl & I think they are the only manufacturer Lundahl will supply with them. But the Vida measures extremely well and seems to have good sample to sample consistency. A friend has made a handful of valve LCR stages but generally uses a 7K5 network rather than 600 Ohm. They have to be hand adjusted but they do sound really good once done.
 
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G T Audio said:
With any LCR phono stage, I would want to see an accurate RIAA plot to verify how accurate the EQ is on each individual phono stage. Winding accurate inductors is both time consuming and very expensive as there is a lot of waste. Many have to be discarded if they don't meet the close tolerances. My bet is that many out of tolerance inductors are still used in production due to the costs involved in discarding them. I've also had first-hand experience of this.
Performance-wise it is very difficult, in fact, it is almost impossible to properly drive a 600 ohm EQ network with a valve/tube circuit, which is why many LCR networks have greater impedances then 600ohms. I have seen 10K networks used but these are not supposed to sound as good as the lower impedance ones. It is much better to use a solid-state circuit to drive a 600ohm LCR network.
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Valab is solid state, designed and hand-built by an honest person. He is extremely meticulous in his sourcing and quality.
 
Tarzan said:
Learning question; what is a LCR phono stage, and why do folk seem to like them?:)
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I am sure there will be more precise explanations, but LCR uses inductors for the EQ network, in addition to capacitors and resistors. Standard RIAA network implementation is with capacitors and resistors only. Addition of inductors allows for the use od much lower values of resistors.
 
pure sound said:
Aurorasound get their eq inductors from Lundahl & I think they are the only manufacturer Lundahl will supply with them. But the Vida measures extremely well and seems to have good sample to sample consistency. A friend has made a handful of valve LCR stages but generally uses a 7K5 network rather than 600 Ohm. They have to be hand adjusted but they do sound really good once done.
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Indeed Guy, Aurasound would be the only LCR stage I would buy if I was in the market for an LCR phono stage.

I have several sets of Lundahl RIAA inductors and found the variations in tolerance were too big to guarantee accurate equalisation. I had several conversations with Lundahl about this and he doesn't like making them because it is extremely difficult to achieve the correct tolerance. I experimented years ago with the classic Tango EQ 600P network (I still have 2 pairs of these :)) but I decided to go a different route as I don't believe in using exotic almost impossible to get valves, which is what you need to drive a 600-ohm network. I believe if you make something it should be serviceable for decades and valves should be easily obtainable and at affordable prices. I notice that a few manufacturers design and sell products that tie you you up to them. They design around a very obscure valve that only they have stock of, so when the valves need replacing they can charge you a fortune for the replacement set of valves. Having spent many years developing valve phono stages, I found the biggest difference, apart from the choice of parts, was going passive RIAA. That way you get most of the benefits of LCR but none of the disadvantages. In fact, I think the capacitor gets are really bad rap. That mostly comes from years ago when parts were not that great but today there are some stunning sounding capacitors available.
 
DimitryZ said:
I am sure there will be more precise explanations, but LCR uses inductors for the EQ network, in addition to capacitors and resistors. Standard RIAA network implementation is with capacitors and resistors only. Addition of inductors allows for the use od much lower values of resistors.
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The idea with an LCR phono stage is that the equalisation network has a constant impedance by frequency as this is what the first gain stage works into. In reality there are small differences due to the DCR of the inductors which need to be taken into account in the rest of the component values.

Re accuracy of the inductors, I recently built an LCR stage using coils from Sowter built to the spec I worked out, and the EQ was basically spot on.
 
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