WhatsApp Image 2023-04-15 at 9.14.21 AM by Richard Howard, on FlickrI have owned this for a couple of years and it has been great with my Tannoys (and pretty much everything else). I put it up for sale a few months ago, and during the process, there were a few issues pointed out by a couple of potential buyers. The amp had been previously modified in a less than suitable manner, so I got assistance from another friendly PFMer, who has carried out the following:
WhatsApp Image 2023-04-15 at 9.03.49 AM (1) by Richard Howard, on FlickrKemet PSU capacitors measure as new, all signal capacitors are Soviet K73-16. Pentode outputs are AN Niobium 0.5w resistors, grid stoppers are Kiwame 2W. Input cathode resistors are Kiwame and bypass cap is an AN Kaisei BP. All wires have been very carefully checked for corrosion and joints re-made. The pentode bias resistors are Mills MRA 5W. Local power capacitors are either PEG124 or K50-27. All solder flux cleaned away with IPA/ deoxit.
WhatsApp Image 2023-04-15 at 9.03.49 AM by Richard Howard, on FlickrThe blue Nichicon is the supply to the pre-amp, should a Radford umbilical be used. And the rectifier diodes have been replaced with modern UF items. All original parts de-soldered (not cut out) and retained.
The internal pic is before the traffo resistor an the Niobium pentode resistors were fitted
Mills MRA12 resistor fitted after transformer in accordance with Radford service instruction (C5-766), felt feet fitted to transformer, Bolts threadlocked with loctite 271, earth bonding maintained. This dropped the classic Radford background hum to almost inaudible levels – highly recommended!
WhatsApp Image 2023-04-15 at 8.50.56 AM by Richard Howard, on FlickrQuiescent noise into 8 Ohms as follows:
WhatsApp Image 2023-04-15 at 8.51.52 AM by Richard Howard, on FlickrThat's 300uV per channel - extremely good by any std. DC offset is shown as 0.2mV, but in reality this is meaningless due to the amp having output transformers.
The output impedance switches have been carefully bypassed, due to them being gummed up to the point where disassembly / replacement will be required, impedance is set at 8 Ohms.
Bias was then set to 1.75v.
Cosmetically, it's not perfect (it is 60 or so years old!). The valve 'trays' are a bit tarnished and the RCAs have seen better days, but that is for the next owner to decide, along with the impedence switches.
It is a beautiful sounding amp. Somewhere between a Bedini 25/25 and a Transcendent Son-of-Beast OTL was how it was described. I just felt it was a magical amp with the Cheviots.
I will be sad to see it go, but I need to come up with a bit of £££, as another expensive hobby is in need of a cash injection and i feel that my Nuvista 300 is probably going to be a bit more practical.
I am in Wiltshire, but work in Bristol. I also get about a bit for work, so we can probably sort out some kind of meet up.
I am after £1,800.
I have spare valves that I am also open to discuss...
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