Hi LH,
Here is my EAR 834P Phono Clone.
It all began in 2018 when I started reading through all the threads. I decided to order the assembled Xouling boards as I did not think I was up to soldering them. I lost the sight in my left eye from a stroke in 2013 which has really affected my up-close sight due to the blurriness from the left.
I then researched which transformer to buy and came across Primary Windings in the UK and contacted them.
I sent them links in relation to the EAR Clone and they designed and built the transformer
PWHT05 250V @80MA 6.3V @ 2A PRE-AMP RIAA VALVE TRANSFORMER
http://primarywindings.com/product/pwht05-200v-80ma-6-3v-2a-pre-amp-riaa-valve-transformer/Description from website
This transformer was inspired by the EAR 834P RIAA pre-amplifier, but may be used in many other designs.
Being a pre-amp the spec on this transformer is very conservative. It is designed with very low flux density, and high quality M6 laminations, meaning the magnetising current is tiny, and the stray flux is very small.
This would normally be enough for a pre-amplifier transformer, but we went further, and added a bright copper flux band, to reduce any stray flux down to almost nothing.
The fact that the magnetising current is so small ensures the mag current waveform is still quite sinusoidal meaning less harmonics to be generated. This is much better than a typical toroidal transformer, where the mag current is high, and is very distorted, generating lots of harmonics.
The copper band makes the transformer look great.
Primary voltage: 220, 230, 240 and 250V.
Secondary: 250V @ 80mA. 6.3V @ 2A Centre tapped.
All high voltage windings use grade 2 enamelled wire for safety and longevity
The heater winding is doubly insulated from the HT winding, and is designed to give long life.
John also designed and built a suitable choke.
Description
A superb quality DC choke for any valve project.
Hand made in the United Kingdom
Constructed using high grade grain orientated M6 0.35mm lamination.
Double insulated.
Flash tested at 2.5KV,
Weight 480g.
DC resistance 500 Ohms]
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http://primarywindings.com/product/20-henry-50ma-dc-choke/I then sat on the project for a while until I came across Rexton’s thread on his clone built by Firebottle. I messaged Alan aka Firebottle to see if he would be willing to build mine for me and I sent my parts to him not long after Christmas.
It took a while to decide on the case and eventually Alan found one for me that I liked.
Alan built it with two MM inputs and the option for loading for different cartridges as well as some of his mods
Alan was a pleasure to deal with and very patient with me and my questions.
Once I received the completed amp back I had to decide on which 12AX7 valves to fit. From the start I decided to go with new production valves as I cannot afford expensive NOS valves at this stage and season of life. After reading some forums I decided to go with JJ ECC803S Matched Valves from Karltone. You can see that the specs are all identical.
I have installed the valves but now need to connect it to my system which will probably have to wait till next week when the kids are back at school after half term.
I have had to learn to be patient in life especially after a stroke as fatigue is a big issue, but I am getting there. I will be connecting the pre to my recently acquired WD 88VA KT88 XL valve amp.
Funds are very low now so I will have to start selling some of my HiFi to build them back up again.
Once I have connected everything up and listens for a while I will try and write something up.
A big thanks to Spaceistheplace for introducing and helping so many on this forum with this project.
Later in the year I hope to be able to put together my CNC MM preamp supplied and very kindly built by Sachu
for me and compare it with the EAR 834P (Firebottle) Clone
Thanks for watching
