Quad Mullard XF4s, UK, £260

[playloud]

These look decent to me: https://www.ebay.co.uk/itm/Mullard-EL34-XF4-B0E4-Set-of-4-Valves-Tested-Matched/175316596316

 

[StingRay85]

Yeah those are new, for sure. B0E4 is really the last batch of EL34 ever made in Blackburn. I have one from F1 but that's it. I have 6 with date code B0E4, including 4 new on box, and they measure not matched at all. Ranging from 22.2 to 39.7 mA for 400 V -36V bias. Seems like the QC section was already abandoned. So I would not be spooked by the 10/15 rating on the little Orange tester

 

[Arthur Winter]

https://www.ebay.com/itm/114693526386?mkcid=16&mkevt=1&mkrid=711-127632-2357

These are the only quad’s I’ve owned so far. I’m surprised the link is still active. It was March 5th 2021

 

[playloud]

https://www.ebay.com/itm/114693526386?mkcid=16&mkevt=1&mkrid=711-127632-2357

These are the only quad’s I’ve owned so far. I’m surprised the link is still active. It was March 5th 2021

Might only be active for you (because you're logged in). Shows as "expired" to me.

 

[Beryllium-9]

Yeah those are new, for sure. B0E4 is really the last batch of EL34 ever made in Blackburn. I have one from F1 but that's it. I have 6 with date code B0E4, including 4 new on box, and they measure not matched at all. Ranging from 22.2 to 39.7 mA for 400 V -36V bias. Seems like the QC section was already abandoned. So I would not be spooked by the 10/15 rating on the little Orange tester

These codes look like B1C2 which seem later than what you indicated. No Blackburn here either I suppose?

1970's Mullard el34 matches pair XF4 NOS UK 6ca7 | Reverb

Here for sale a matched pair of Mullard el 34 XF4 model. They bear the Philips label and were made in England in the famous Mullard Blackburn factory, both in the 70's. Work fine, test strong, no issues. Getting more difficult to find. Check the photos and let me know should you have any q...

reverb.com

 

[StingRay85]

These codes look like B1C2 which seem later than what you indicated. No Blackburn here either I suppose?

1970's Mullard el34 matches pair XF4 NOS UK 6ca7 | Reverb

Here for sale a matched pair of Mullard el 34 XF4 model. They bear the Philips label and were made in England in the famous Mullard Blackburn factory, both in the 70's. Work fine, test strong, no issues. Getting more difficult to find. Check the photos and let me know should you have any q...

reverb.com

One of them is XF2 with welded plates, from '71, the other one is XF4 from '77. Both Blackburn for sure.

Always be careful when they are not showing the getter flash from the other side. Surface corrosion on the pins.

Surely not worth a premium price

 

[Beryllium-9]

One of them is XF2 with welded plates, from '71, the other one is XF4 from '77. Both Blackburn for sure.

Always be careful when they are not showing the getter flash from the other side. Surface corrosion on the pins.

Surely not worth a premium price

Cool..!! You are really sharp with tubes!! Someday I will take the time to learn more. I made a stupid offer on these and it was accepted...

Mullard EL34 Vacuum Tube - 2 Piece for sale online | eBay

Find many great new & used options and get the best deals for Mullard EL34 Vacuum Tube - 2 Piece at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[StingRay85]

Cool..!! You are really sharp with tubes!! Someday I will take the time to learn more. I made a stupid offer on these and it was accepted...

Mullard EL34 Vacuum Tube - 2 Piece for sale online | eBay

Find many great new & used options and get the best deals for Mullard EL34 Vacuum Tube - 2 Piece at the best online prices at eBay! Free shipping for many products!

www.ebay.com

I don't know what you offered, but in my opinion these kind of tubes are only worth a shot below 20 $ a piece. They seem to have been severely cooked. But who knows, they might still sound good

 

[Seanxk]

Someday I will take the time to learn more. I made a stupid offer on these and it was accepted...

Mullard EL34 Vacuum Tube - 2 Piece for sale online | eBay

Find many great new & used options and get the best deals for Mullard EL34 Vacuum Tube - 2 Piece at the best online prices at eBay! Free shipping for many products!

www.ebay.com

They may test ok on a tester, but these have been red plating, you can just see but he has been clever with his pictures. If you put them in an amp they will show red plating again, so bias these colder rather than hotter.
Another thing these guys on ebay do is not disclose the Heater Cathode leakage ( a most dangerous thing for your amp ), most haven't a clue what it is even if the tester has the option, but the big valve sellers do know, whether they disclose or not.

 

[Beryllium-9]

They may test ok on a tester, but these have been red plating, you can just see but he has been clever with his pictures. If you put them in an amp they will show red plating again, so bias these colder rather than hotter.
Another thing these guys on ebay do is not disclose the Heater Cathode leakage ( a most dangerous thing for your amp ), most haven't a clue what it is even if the tester has the option, but the big valve sellers do know, whether they disclose or not.

Good point Sean! I need tubes but don't want spend crazy money for them. I probably got screwed here. Oh well.. I am in California so I am used to it. A tank of petrol costs much more than what it paid. I will report back when they arrive..

 

[playloud]

Good point Sean! I need tubes but don't want spend crazy money for them. I probably got screwed here. Oh well.. I am in California so I am used to it. A tank of petrol costs much more than what it paid. I will report back when they arrive..

If you have a light bulb limiter, use that with your amp when you first try them out. Return the tubes if the bulb remains bright.

If you think petrol prices in CA are high, you should check out the UK/Europe! (Admittedly, the typical "tank" is probably smaller there...)

 

[StingRay85]

The heaters will always pull current, so I don't think that's a reference

 

[playloud]

Here's another good-looking quad:

https://www.ebay.co.uk/itm/175649361463

 

[StingRay85]

That's actually pretty reasonable for a real NOS matched quad. B0E4 are the last batch of EL34 made in Blackburn, so this is left over stock. In my experience, the Xf4 are the strongest version made by Blackburn.

If you're looking for a quad of real Mullards, grab them before they are gone

 

[Seanxk]

So they're matched because his Orange says so, really?

Edit, same seller as OP heading, he either has a stash or they got returned.

 

[StingRay85]

Good point. Ask him

 

[Seanxk]

Good point. Ask him

It's most likely Orange' fault in advertising " Make sure your amp runs perfectly by matching valves with our machine '' or something like that. We know it's far from that simple

 

[StingRay85]

I don't have experience comparing values of the Orange tester to e.g. my MaxiMatcher 2. I do know that tubes that match on 250V, do not necessarily match as good on 400V.

 

[Seanxk]

The Maximatcher is as it's name and one of a very few that are dedicated to matching, the orange I'm sure is just testing Goodness.
I have an AVO CT160 and a VCM163, neither will match power valves. I would like a Maxi, but for now I just match pairs using a 50w amp.

The other confusing thing is you don't actually want matched in a 50w and only matched pairs in a 100w.

 

[StingRay85]

I do think the Orange valve tester is also made to more-or-less match power tubes. He mentions all measure at 11/15. I assume it puts the tube in fixed bias with control grid at e.g. -12V with 250V on anodes and screens, and the output current is measured and scaled between these values.