Does anybody do this - fit 2 different type sockets in your amp to try alternative tubes?
I first did it with rectifiers, an octal and a UX4 socket next to each other so I could use 5U4 or 5Z3. And just now I fitted a pair of Y8A sockets and a pair of side contact sockets to one amp so I can use EL12n or EL6. But as I was doing so I realised that these old sockets, which were used in enclosed radios, have very exposed connections with voltage on them. Particularly side contact sockets. So I'll have to make a cover for the sockets not in use. This is not difficult to do.
Most people use Chinese socket adapters so the problem doesn't exist, but I'm wondering what you guys do if you fit alternative socket types?
I first did it with rectifiers, an octal and a UX4 socket next to each other so I could use 5U4 or 5Z3. And just now I fitted a pair of Y8A sockets and a pair of side contact sockets to one amp so I can use EL12n or EL6. But as I was doing so I realised that these old sockets, which were used in enclosed radios, have very exposed connections with voltage on them. Particularly side contact sockets. So I'll have to make a cover for the sockets not in use. This is not difficult to do.
Most people use Chinese socket adapters so the problem doesn't exist, but I'm wondering what you guys do if you fit alternative socket types?
What kind of plug in modules were you thinking? It would need a suitable connector - do you have any in mind? Could be an idea.
Why not use (make) "universal" test adapters?
sample:
https://www.ebay.co.uk/itm/285602274947?customid&toolid=10050
sample:
https://www.ebay.co.uk/itm/285602274947?customid&toolid=10050
Thanks for that idea, but far too expensive and wouldn't really fit an amplifier. I still think that covering the unused sockets is the best plan so far.
I did think of these - rated 450V AC:
https://cpc.farnell.com/camdenboss/ctsn433-12mf/10a-terminal-strip/dp/CN00144?st=terminal stips
I did think of these - rated 450V AC:
https://cpc.farnell.com/camdenboss/ctsn433-12mf/10a-terminal-strip/dp/CN00144?st=terminal stips
I've thought a lot about this subject too. It started with the idea to build an amp that can use both 6L6s and 807s, as I have plenty of both.
No problems so far, as they are pretty much the same thing.
Later the idea grew into a monster with adjustable B+, adjustable grid bias, adjustable heater voltage (why not clean DC/CCS to allow DHTs?) and even OPTs with multi-tapped primary windings for different plate loads and detachable modules for the output tubes to allow a very wide range of tubes to be used/tested.
This would be an excellent project for someone like me, who has a small collection of weird tubes in smaller numbers and a lot of ideas of how to use them but lacks the resources to build a new amp for every new power tube.
No problems so far, as they are pretty much the same thing.
Later the idea grew into a monster with adjustable B+, adjustable grid bias, adjustable heater voltage (why not clean DC/CCS to allow DHTs?) and even OPTs with multi-tapped primary windings for different plate loads and detachable modules for the output tubes to allow a very wide range of tubes to be used/tested.
This would be an excellent project for someone like me, who has a small collection of weird tubes in smaller numbers and a lot of ideas of how to use them but lacks the resources to build a new amp for every new power tube.
I built an amp some years ago with both octal and noval sockets for the driver stage. I could swap tubes assuming a similar operating point detail. The tubes were for dual triodes used in a differentical stage with a CCS tail. The CCS in the tail allowed for trying different tubes and knowing what the bias currents would be. It worked fine but they were low and medium mu tubes. The excess wiring between the sockets could be a possible cause for oscillation with higher transconductance tubes.
Oscillations might become a problem with high gm tubes and parallell sockets, yes.
I'm imagining small pcbs with sockets and grid resistors on, plus some kind of headers for the connections. Preferably two or more rows, for mechanical stability.
These pcbs could then be sandwiched with pieces of alu sheets or similar that fits in cutouts in the chassis. That way it could all be both safe and decent looking.
I'm imagining small pcbs with sockets and grid resistors on, plus some kind of headers for the connections. Preferably two or more rows, for mechanical stability.
These pcbs could then be sandwiched with pieces of alu sheets or similar that fits in cutouts in the chassis. That way it could all be both safe and decent looking.
I'm using the dual sockets for output tubes, so the extra wire should not cause oscillation. Fortunately the operating conditions are the same between parallel E80L and single EL12n (triode wired) which I have in one amp. And EL6 and EL12n in another amp (triode wired) except that the EL6 has a maximum of 250V on the anode and the EL12n can go much higher. But that's just a case of a dropper resistor on the B+.
I'm like Fuling - I like the older and rarer kinds of tubes, especially European, with odd sockets. They do sound good.
I'm like Fuling - I like the older and rarer kinds of tubes, especially European, with odd sockets. They do sound good.
I spent quite some thoughts in this as well. As I am mostly working on actual circuits and not afraid of SS and high transconductance tubes, I have encountered the oscillation grimlings all too often, so indeed I use stoppers close to the sockets, limit wire length, and so on. This all speaks against "universal solutions". But I did some things anyway.
Years ago I bought a lot of these 6 pole socket connectors from surplus https://eu.mouser.com/ProductDetail/Weidmuller/1646290000?qs=WJDKaGZ8K%2B5oR0cR3wCRRA==&_gl=1*4ynsnu*_ga*MTg0NTY3MTQxNC4xNzA3OTA3ODky*_ga_15W4STQT4T*MTcwNzkwNzg5MS4xLjAuMTcwNzkwNzg5Mi41OS4wLjA.*_ga_1KQLCYKRX3*MTcwNzkwNzg5Mi4xLjAuMTcwNzkwNzg5Mi4wLjAuMA..
These are the counterpart for the more common plugs, an example here https://www.mouser.ch/ProductDetail/Wurth-Elektronik/691311500112?qs=sPbYRqrBIVmDNvdFlqYq/A==
In my builds, generally the socket is the fixed part of the amplifier, the plug contains the active parts (exchangeable). I use it a lot for all sort of mosfets I use in my builds, but also for eg input transformers, thinking about using it for VR tubes. There are also plugs with screw or spring connections, these would allow one to attach a (coupling) cap or so straight to the plug, and insert that in the socket for fast replacement of the component. example https://www.distrelec.ch/en/pluggable-pcb-connector-straight-08mm-pitch-poles-phoenix-contact-1786190/p/30107665?trackQuery=cat-DNAV_PL_041106&pos=771&origPos=19&pageSize=50&origPageSize=50&track=true&sort=Price:desc&filterapplied=filter_Gender=Header&filter_Pitch%7E%7Emm=5.08&sid=ead3d0baba211f5fd8d2a6bd4c7ac1b82bd663f1&itemList=category
To attach these to the chassis and to solder to them I use these PCBs https://www.ebay.de/itm/28550928320...4BVKXH&hash=item4279aded88:g:mkUAAOSwVvRkgCyV , These have traces wide apart, gives me peace of mind in the HV builds with tubes. These are also available in cheaper quality from eg Reichelt.
I have some other solutions for tube sockets that I built throughout the years and am still using, but I could well imagine that it can work as well. I actually thought of making the PCBs (with two rows of plugs on one side of the PCB, and the socket on the other side) as a first exercise to learn PCB manufacturing SW, but never got to it. Bit hard to keep heater separated, so maybe go with DC heating (it is becoming easier, and even cheaper than AC heating... just compare the price of a 100W DC supply from Meanwell with a 100VA toroidal transformer...)
These are certainly not audiophile approved 🙂, but proven quite reliable: a former employer used them in the electronics of ship engines, and they never had one failing.
Years ago I bought a lot of these 6 pole socket connectors from surplus https://eu.mouser.com/ProductDetail/Weidmuller/1646290000?qs=WJDKaGZ8K%2B5oR0cR3wCRRA==&_gl=1*4ynsnu*_ga*MTg0NTY3MTQxNC4xNzA3OTA3ODky*_ga_15W4STQT4T*MTcwNzkwNzg5MS4xLjAuMTcwNzkwNzg5Mi41OS4wLjA.*_ga_1KQLCYKRX3*MTcwNzkwNzg5Mi4xLjAuMTcwNzkwNzg5Mi4wLjAuMA..
These are the counterpart for the more common plugs, an example here https://www.mouser.ch/ProductDetail/Wurth-Elektronik/691311500112?qs=sPbYRqrBIVmDNvdFlqYq/A==
In my builds, generally the socket is the fixed part of the amplifier, the plug contains the active parts (exchangeable). I use it a lot for all sort of mosfets I use in my builds, but also for eg input transformers, thinking about using it for VR tubes. There are also plugs with screw or spring connections, these would allow one to attach a (coupling) cap or so straight to the plug, and insert that in the socket for fast replacement of the component. example https://www.distrelec.ch/en/pluggable-pcb-connector-straight-08mm-pitch-poles-phoenix-contact-1786190/p/30107665?trackQuery=cat-DNAV_PL_041106&pos=771&origPos=19&pageSize=50&origPageSize=50&track=true&sort=Price:desc&filterapplied=filter_Gender=Header&filter_Pitch%7E%7Emm=5.08&sid=ead3d0baba211f5fd8d2a6bd4c7ac1b82bd663f1&itemList=category
To attach these to the chassis and to solder to them I use these PCBs https://www.ebay.de/itm/28550928320...4BVKXH&hash=item4279aded88:g:mkUAAOSwVvRkgCyV , These have traces wide apart, gives me peace of mind in the HV builds with tubes. These are also available in cheaper quality from eg Reichelt.
I have some other solutions for tube sockets that I built throughout the years and am still using, but I could well imagine that it can work as well. I actually thought of making the PCBs (with two rows of plugs on one side of the PCB, and the socket on the other side) as a first exercise to learn PCB manufacturing SW, but never got to it. Bit hard to keep heater separated, so maybe go with DC heating (it is becoming easier, and even cheaper than AC heating... just compare the price of a 100W DC supply from Meanwell with a 100VA toroidal transformer...)
These are certainly not audiophile approved 🙂, but proven quite reliable: a former employer used them in the electronics of ship engines, and they never had one failing.
Hi Andy
Seeing your recent trend toward DH drivers feeding IDH power valves and reading that you've tried various in both positions, I thought to mention that I have travelled a similar route and fixed on a CV9 (AL60) in UL mode - driven by a choke loaded VR21, a little 2v'er that I think you tried as well. The CV9 is excellent and cheap! Only downside, B7 base and 4v htr but for someone using EL12's, not a problem.. If you don't mind top caps of course......
David.
Seeing your recent trend toward DH drivers feeding IDH power valves and reading that you've tried various in both positions, I thought to mention that I have travelled a similar route and fixed on a CV9 (AL60) in UL mode - driven by a choke loaded VR21, a little 2v'er that I think you tried as well. The CV9 is excellent and cheap! Only downside, B7 base and 4v htr but for someone using EL12's, not a problem.. If you don't mind top caps of course......
David.
CV9 is quite rare but yes - like an EL12 or EL6. Good choice if you have some. Should sound very nice.
VR21 - so cool! That's a very esoteric combination. Great!
VR21 - so cool! That's a very esoteric combination. Great!
@ErikdeBest , I looked at your links to connectors and pc board. Any chance you could share some pictures of your implementations with these parts? I'd like to try some of your prototyping ideas.
Thanks,
John
Thanks,
John
I've done it, but only where the tubes are close enough that most of the circuit is the same.
This amp uses either R120 IDHT or PX4 DHT tubes. The switch just flips the heater / filament supply between 6.3VAC and 4VDC. It's cathode biased and the same arrangement works for both tubes.
Pete
This amp uses either R120 IDHT or PX4 DHT tubes. The switch just flips the heater / filament supply between 6.3VAC and 4VDC. It's cathode biased and the same arrangement works for both tubes.
Pete
IF you’re just testing between 8 and 9 pin drivers there are lots of plug in adaptors you can use. I have several wired for different pin outs for different bases. Stuff like 6cg7 to 6sn7 is easily available. They’re not dirt cheap but worth it if you want to test without rewiring.
That's quite a collection of adapters!
I've been checking some bungs for filling the side contact sockets when not in use, which are 27mm ID. Ordered these, the black one is 27mm:
I've been checking some bungs for filling the side contact sockets when not in use, which are 27mm ID. Ordered these, the black one is 27mm: