I'm sure this question has already been answered, but not easy to find the answer in this long thread.
I'm going to connect the PSU chassis to the preamp chassis with 2 quadripolar umbilicals.
I have raw supplies in the PSU chassis, shunt regulator and Colemans in the preamp chassis, full dual mono after the first quasi-choke CL, so I have to carry 2x high voltage and 2x filament voltage.
I'm going to use one quadripolar for high voltage and one for low voltage twisting each pair.
Is that correct?
Can I use two quadripolar cables (not twisted)? Shell I go for a shielded quadripolar? Tnx!
I'm going to connect the PSU chassis to the preamp chassis with 2 quadripolar umbilicals.
I have raw supplies in the PSU chassis, shunt regulator and Colemans in the preamp chassis, full dual mono after the first quasi-choke CL, so I have to carry 2x high voltage and 2x filament voltage.
I'm going to use one quadripolar for high voltage and one for low voltage twisting each pair.
Is that correct?
Can I use two quadripolar cables (not twisted)? Shell I go for a shielded quadripolar? Tnx!
For the filaments a 4 pole XLR connector is an option, and twist the pairs.
For a HT connector I'm open to ideas. Maybe a SHV connector?
shv connector - Google Search
For a HT connector I'm open to ideas. Maybe a SHV connector?
shv connector - Google Search
Useful looking connectors, but the multi-pole ones are only rated 32v. The 2-way connectors say "125(250)v" whatever that means.
Bayonet IP40 - Franz Binder GmbH & Co. Elektrische Bauelemente KG
Looks pretty unsafe to put a Speakon socket on a PSU with the HT going through it in case someone connects a speaker to it. Less risky to put one on the signal chassis since connecting a speaker to it with no HT present is in theory possible (but consider necessity of discharging any HT capacitors). A Powercon white (output only) would be better on a PSU chassis, but while it would work it's again not ideal. The Neutrik sockets are completely shrouded at least.
There are no obvious widely available options here, not even the SHV connectors. This has all been discussed at length.
Male panel mount connector, cable outlet 4-6 mm - Franz Binder GmbH & Co. Elektrische Bauelemente KG
Male cable connector - Franz Binder GmbH & Co. Elektrische Bauelemente KG
These entries do indeed say 250v. Hmmmm....... bit unclear.
Look for Switchcraft Conxall Mil-e-qual connectors. They are the cheapest HV rated connectors I found at the big suppliers. Decent quality, several shell sizes and pin configurations available. Easy to work with, too.
One advantage is that there is only one way they make each configuration, so it is easy to find its male/female mate. (If you’ve ever tried finding two mating connectors out of the Amphenol catalog, you may know what I am speaking of.)
As for shielding, I personally found it helpful to use shielded umbilical cable. The shield cut a very audible amount of noise. Braided shield can be added anytime later, so you can try it unshielded at first.
Best regards,
John
One advantage is that there is only one way they make each configuration, so it is easy to find its male/female mate. (If you’ve ever tried finding two mating connectors out of the Amphenol catalog, you may know what I am speaking of.)
As for shielding, I personally found it helpful to use shielded umbilical cable. The shield cut a very audible amount of noise. Braided shield can be added anytime later, so you can try it unshielded at first.
Best regards,
John
Pics or it didn't happen
Attached is a pic of my build. This is my first tube project and so I wanted it to be in a form that is easy to troubleshoot. PS is to the left and main circuit to the right--both in the same chassis. I'm not getting any hum at all.
Thanks to Rod and Ale for the boards and circuit design. Thanks to Amandarae for the B+ PS design, I just copied his. Thanks for everyone else for the support on this thread. What an amazing community we have here! Long live diyaudio.
The sound is very clean. Top and bottom end are fully there. I tried bypassing the source follower, but the top end falls off a cliff, i.e., sounds muffled. I didn't put it on the test bench for measurements, but suffice to say that the follower is needed. Unless, the output cap is too small. It is 220nF with a 680k resistor to ground. This is the circuit I'm using:
https://i1.wp.com/www.bartola.co.uk/valves/wp-content/uploads/2016/11/26-Preamp-Gen3.png
Driving the F4, it gets plenty loud, so there is enough gain. It sounds very clean and very good, but I was expecting more. I cannot adjust the anode voltage above 140 V using the gyrator board pot. I'm going to send Ale an email to see if there might be problem with that. Also, the shoulder type 26 tubes sounded very ordinary. The globe types are a massive improvement.
Attached is a pic of my build. This is my first tube project and so I wanted it to be in a form that is easy to troubleshoot. PS is to the left and main circuit to the right--both in the same chassis. I'm not getting any hum at all.
Thanks to Rod and Ale for the boards and circuit design. Thanks to Amandarae for the B+ PS design, I just copied his. Thanks for everyone else for the support on this thread. What an amazing community we have here! Long live diyaudio.
The sound is very clean. Top and bottom end are fully there. I tried bypassing the source follower, but the top end falls off a cliff, i.e., sounds muffled. I didn't put it on the test bench for measurements, but suffice to say that the follower is needed. Unless, the output cap is too small. It is 220nF with a 680k resistor to ground. This is the circuit I'm using:
https://i1.wp.com/www.bartola.co.uk/valves/wp-content/uploads/2016/11/26-Preamp-Gen3.png
Driving the F4, it gets plenty loud, so there is enough gain. It sounds very clean and very good, but I was expecting more. I cannot adjust the anode voltage above 140 V using the gyrator board pot. I'm going to send Ale an email to see if there might be problem with that. Also, the shoulder type 26 tubes sounded very ordinary. The globe types are a massive improvement.
Attachments
I think a GX16-4 connector should be OK for HT, isn't it?
CONNECTOR-GX16-4
It is rated as follows:
FEATURES
- Rated Voltage/Current :20A /220V
- Operation Limit Voltage :AC 250V.rms
- Withstand Voltage: AC 1000V
- Insulation Resistence: Max. 1200 ohm
- Contact Resistance :20 mOhm
- Pin Quantity: 4 Pin
- Mounting Thread Diameter: 16mm / 5/8"
- Total Length :45mm / 1.8"
Forgot about those - they aren't stocked by Farnell, RS and the usual UK suppliers. Don't know why. They're cheap. Sometimes advertised as 300v. I imagine the 2-pole ones GX16-2 are best suited to high voltages.
I'm leaning more to the Powercon grey output connectors. Use them both ends, PSU and signal chassis since they're shrouded. Designed for AC but very robust.
NAC3MPB-1 | Neutrik
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They do indeed work fine, and I use them too. But I think it's safer to switch to Powercon Bs to avoid any confusion with connecting speakers. Plus you can't connect the mains to the output connectors using the grey B ones. Just in case the amps end up elsewhere.
No insertion or crimp tools necessary. I solder mine, and the pins just push into place. No special tools.
Bigger shell sizes offer more space between the pins, and thus greater ease when soldering.
Best regards,
John
Wow!
In post #5031, I complained that I was expecting more. Boy, is there more!
After fixing the CCS setting resistor in Ale's circuit, the anode voltage could be adjusted to 160 V and what a difference 20 volts can make. This is the best sound I have ever had in my system. There is absolutely no hardness at all. It is liquidy, creamy, smooth. The soundstage is wide and deep with individual instruments clearly separated and the tone is just amazing. Extremely happy now! This is what I was expecting and am really happy.
Would be great to know the filament current and anode voltages the rest of you happy builders are using.
In post #5031, I complained that I was expecting more. Boy, is there more!
After fixing the CCS setting resistor in Ale's circuit, the anode voltage could be adjusted to 160 V and what a difference 20 volts can make. This is the best sound I have ever had in my system. There is absolutely no hardness at all. It is liquidy, creamy, smooth. The soundstage is wide and deep with individual instruments clearly separated and the tone is just amazing. Extremely happy now! This is what I was expecting and am really happy.
Would be great to know the filament current and anode voltages the rest of you happy builders are using.