That looks really good, but it’s a little too much dosh. I suppose good iron and design is never going to be cheap.
Can anyone explain this stocking policy (that’s stock levels, not hosiery, just in case anyone’s blood pressure is already rising …) ?
Farnell are a big online retailer of electronic components. They own a subsidiary, called CPC, who stock a smaller range of the same products, often at significantly lower prices. But CPC’s stock levels are routinely ridiculously small. Why ?
Today’s example is a 1W 15kohm carbon film though hole resistor (Farnell part no 9337750, CPC part no RE04947 if anyone cares). I want 50. Actually I only need 1 - but they cost 8.82p each from Farnell and 7.2p from CPC so why ever be short of them again ? Farnell have a minimum order of 1 and 5,321 in stock, which sounds reasonable. CPC have a minimum order of 10 which would not be a problem except they only have 9 in stock. That’s right, 9.
So I’ve ordered 50 from CPC as part of a bigger order (I don’t like buggering my suppliers about and if the order’s big enough they also do free delivery). In a day or three 9 will turn up and then in a few weeks they’ll have to make a dedicated delivery for the remaining 41. They won’t charge me for that, and they use UPS !
So, how on earth can that possibly make business sense ? I’m just curious, that’s all.
VB
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I stopped reading when you clarified what you meant by stocking. Good luck with the thread though🤣!
Amazed to hear they still haven’t sorted this nonsense out. They don’t seem to have a restocking algorithm that takes account of how in-demand a component is, so they’ll show 100,000 of some rare resistor they’ve probably had in-stock for 20 years, but be forever out of stock of 330R / 0.5W…
Mind, Ocado are World leaders at a similar business model, and they are every bit as patchy and irrational…
How much do they pay UPS per delivery?
Good question. If they’ve actually negotiated a literally fixed-price deal - we pay you X and you have to deliver everything - then that could be part of the explanation. But they’d still have to print out a despatch note and get someone to separate my 41 resistors from the large incoming delivery and put them, plus note, into a jiffy bag. The ‘profit’ on 41 resistors can’t even cover that.
I also don’t understand why the more expensive, lower minimum order item comes from the part of the organisation with the smallest stock. Surely it should be the other way round ?
VB
It probably depends on how often they check stock levels and generate an order to replenish it. There’s also a lot of ‘stuff’ stuck in containers on cargo ships moored outside ports throughout the world. It’s affecting all sorts of manufacturing.
I have been digging through my shelves of stuff, and came across a pair of old Partridge TH4663/2 transformers.
As far as I can work out, they are SE OTX suitable for 300B / PX25 etc, but I have been unable to find any info on how to connect them up!
Obviously, I could just follow what is already there, but I was thinking about how to change from 4 to 8 ohm secondary? or the reason for the various primary taps?
Does anybody have any info on these they would be able to share?
Thx
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All I could find was this, but as it is a dead listing, the info provided, you probably already know. But if you can find out who he was, he had connection instructions.
Partridge 2x th4663/2 if Output transformers NOS 300b px25 …[image]
https://www.ebay.com/itm/2X-PARTRIDGE-TH4663-2-SE-OUTPUT-TRANSFOR…
2X PARTRIDGE TH4663 /2 SE OUTPUT TRANSFORMERS NOS 300B PX25 Jean Hiraga vintage 2,3 e 3,5 k out 4 to 16 ohm 100mA Primary inductance 20 H Power 30W, frequency response 20 Hz to 100 kHz The connection schemes, if necessary, will be provided to the buyer when the object is sold and paid for.
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Seller Rating: 100.0% positive
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Location: SASSARI, Italy
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Shipping: Free
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nice 
I think the TK4519 was used by Hiraga in his 300B amp
yes, it seems the TH4663 is the same as TK4519, but in a can
Primary can be either 2K3 (I guess with 3 and 4 bridged) or 3K5 (with 1 and 2 bridged.
So good for 45, 2A3, 6B4G, PX4, PX25 or 300B
Secondaries can be arranged for 1, 4, 8 or 16 ohms
These look tatty enough to be original Partridge made, rather than the Transformers and Rectifiers re-made versions
need to lash them into something and give then a try!
Performance looks promising, see page 9:
http://www.tubesoundelectronics.de/tabellen/messtabelle_ot_etf2009.pdf
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I quite like occasionally buying and putting together little kits. One recent acquisition was a pair of PCBs for a JFet phono stage. I’ve been aware of a phono circuit called the Pacific based on 2sk170s.
The very neat, nicely made boards turned up and I began gathering together the bits I didn’t have already. I had a couple of supposedly well matched and kosher GR grade 170s which would do for the first stage but I also had a bag of 10 of somewhat unknown provenance. I’d also, a while back, bought a kit for a FET testing device.
A very basic but perfectly good enclosure arrived so I fitted sockets, ground post and some mounting points for the two PCBs.
Empty board
Stuffed board
This evening I finished the second board. This design runs from 18v so to begin with I’ll run it from a pair of stacked 9v batteries and see how we get on. Hopefully it’ll be running tomorrow. I’m not expecting this to be as good as a Vida or one of the valve stages I use but I’m interested to see how well it does go. I like that they intended for it to use paper in oil caps and I fortunately had some of the Russian ones here already. There is also a JFet headamp circuit called Le PrePre which is similar in concept so if this is OK I may try that.
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Looks cool. Building a Pearl 2 at the moment. Must sort inverse riaa very shortly.
I built the inverse circuit from Rod Elliott’s site, seems to work ok.
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Cheers, will have a look.
Pondering swapping out the existing SS power supply for the pre/phono stage for skmething with an EZ80 in it (or something like). Apart from the obvious advantage of moar valve faff, any good reasons for going down that route?
The most likely candidate for the trafo (Hammond 260C) also has a 5V winding, but presumably all the rectifiers with a 5V heater are for way more than the 40mA or so I will need?
If the SS supply is competently designed then there won’t be any valve version which measures better in any significant way. The valve rectifier will warm up relatively slowly whereas a simple SS one will be ‘instant on’, which can stress components in the downstream circuitry briefly.
An EZ80’s rated at 350V and 90mA. The weediest of the readily available 5V heater rectifiers is probably the 5Z4 which can go up to 350V and 125mA (it’s available with various envelopes, as designated by the last letter(s) in the valve number - 5Z4, 5Z4G, 5Z4GT etc). If you choose to power the EZ80 off the same 6.3V heater supply as all the other valves then there is a fault mode which may prove expensive, which is breakdown from the EZ80 cathode (at high DC voltage) to its heater, and thence to the other valve heaters. It is also possible for rectification switching noise to leak from the cathode to the heater, and into the other valves’ heaters, and into the other valves’ cathodes, and onto the signal path. In sensitive circuitry that would be A Bad (noisy) Thing if it were to happen.
VB
I do have a spare 6V transformer with 2 10VA windings which can cope with the signal valves (2 ECC88s at 40V elevation and 2 ECC81s and a 6SN7 referenced to ground, all on regulated DC) so the plan would be for the rectifier heater to have its own winding.
A separate winding for the rectifier is good. Two completely separate transformers for a) high voltage and b) audio valve heaters are even better (from a rectification noise point of view - larger physical footprint though).
VB
Hammond 260C has a 6.3V windings for the signal valves, and 5V @ 2A winding for the rectifier,
EZ80 is a 6.3V rectifier, so not a good option, as detailed by @Valvebloke
I would suggest a 5Y3 rectifier, it will be very nice. If you want to blow the budget, try a NOS Mullard GZ34 
Other options include 5R4, 5AR4, 5Z4, 5AZ4, 5V4 or 80 for a 4 pin version of a 5Y3