This may not be any news to most of you, but after a long time I managed to get the upgrade needed on my turntable: the cartridge. The Denon DL103 was a perfect decision to step up into the MC territory at an affordable cost. Many will say out there that there are better cartridges, but that is not the point of my review.
I tried some MM ones and until now couldn’t get the Lenco + Audiomods arm to sound as good as it sounds now. The DL103 is challenging due to its low compliance and output levels.
Although I have a step-up transformer, I’m saving it for my valve phono stage project which I hopefully will get my hands on next year. Currently still have a solid stage RIAA stage made by Project which sounds really good in my opinion. Shortly will complete my JFET shunt cascode RIAA stage and listen to the difference.
Jeff from Audiomods sent me the copper shim for the headshell but my cartridge screws aren’t long enough to fit both. I was worried on the performance by not adding sufficent mass to the arm, but after testing it, I was surprised to see that it was not the case.
The sound performance is really good. No loss in bass or treble, with a flat response, the dynamics are brilliant. Noise level is very low. Tight drums and clearer sound. I like the detail and even playing loud sections it is great. I will continue to listen to this until I can find anything to dislike from it, so far it’s superb.
After enjoying the 4-65a SE amplifier for many months, I couldn’t resist myself to upgrade the output stage to the 814s. I just needed changing sockets and filament raw supply transformers to fit the requirements of this lovely transmitting valve. Needless to say, my recent tests were very encouraging. The 814 seemed to perform much better than the 4-65a in delivering 10W of class A2 sound at half the distortion levels. This to me, was only worth trying.
It’s time for the leap of faith. Having tested the 814 in triode mode, I will proceed now to upgrade my 4-65a SE amplifier and replace output valve for the 814. To ensure it can withstand the 540V in the anode, the remaining grids are all tied together through a resistor to the anode. All grids and anode are fitted with ferrite beads as well. A pair of UF4007 in series are placed to protect the Output Transformer in case load is accidentally disconnected.
UX5 socket prepared
I added to the UX-5 socket a small bar to place two turrets to provide the anode (top connector), the strapped grid connections through the wire-wound resistor and the pair of UF4007 diodes.
Given that the 814 will run @ 540V / 100mA, I will only need to adjust the Rod Coleman regulators to set current down to 3.25A after replacing the raw filament transformers, as the 814 are 10V instead of 6V filaments of the 4-65a.
Minor DC adjustment will be required on the driver circuit via the gyrator load, so can easily implement this new amplifier.