MachMat or Tentlabs Heater Supply for 300B

eeyore · 28th June 2007, 09:59 AM

Hi there, just wondering if anyone has used either the MachMar VCCS and/or TentLabs Tube Filament Supply ? I am planning on using this for a 300B SE? It is touted that these are great for DHT/Directly Heater Triodes. Any experiences/observations/etc? All comments welcomed!

(Before you ask, I am feeling a little lazy building my own one point-point. Why not get a PCB for something like this, nice, simple and discrete. However, if I were to build one point-to-point, what are the various schematics around?)

siang · 3rd July 2007, 02:25 PM

I'm also interested in this also but it seems no one has tried both?

siang

Sheldon · 3rd July 2007, 09:54 PM

I've use the Tentlabs supplies and have been very pleased with the results. Both units are high impedance devices, and probably have high enough bandwidth, so should work similarly. One major difference is that the Tentlabs unit is very low dropout. If you have a 5V winding, you can regulate at 5VDC. It looks like the machmat unit requires at least 3 volts higher for the AC input.

Sheldon

eeyore · 3rd July 2007, 10:46 PM

Sheldon, thanks for sharing your experiences/knowledge. The Tentlabs also seem to offer a better value option, and given you note about the low votlage dropout could be the better option in my opinion.

Let me ask and get this right, you will one board per heater. You cannot parallel or serial multiple tubes with one board?

Sheldon · 3rd July 2007, 11:37 PM

I think in a PP amp you might be able to use one per pp pair (confirm first), but for SE amps, yes, you need a separate winding and power supply per OP tube or per pair (if parallel).

Sheldon

Gerrit Boers · 4th July 2007, 06:59 AM

I used the MachMat VCCS (DC version) because I wanted to use a CRC filter before the regulator. In this case the MacMat was the better choice.
At 1.5 amps the VCCS needs an input voltage that is 4V above the output, this means you have to have a serious heatsink.

My experiments can be found here:
Heater supply part 4

If you want to upgrade the heater supply of an existing amp I think the Tentlabs module would be the preferred choice because of the lower voltage drop.

siang · 4th July 2007, 01:34 PM

thank you all for the valuable information.

28th June 2007, 09:59 AM	#1
eeyore diyAudio Member Join Date: Aug 2005	MachMat or Tentlabs Heater Supply for 300B Hi there, just wondering if anyone has used either the MachMar VCCS and/or TentLabs Tube Filament Supply ? I am planning on using this for a 300B SE? It is touted that these are great for DHT/Directly Heater Triodes. Any experiences/observations/etc? All comments welcomed! (Before you ask, I am feeling a little lazy building my own one point-point. Why not get a PCB for something like this, nice, simple and discrete. However, if I were to build one point-to-point, what are the various schematics around?) __________________ DF http://diy-audio-blog.blogspot.com

3rd July 2007, 10:46 PM	#4
eeyore diyAudio Member Join Date: Aug 2005	Sheldon, thanks for sharing your experiences/knowledge. The Tentlabs also seem to offer a better value option, and given you note about the low votlage dropout could be the better option in my opinion. Let me ask and get this right, you will one board per heater. You cannot parallel or serial multiple tubes with one board? __________________ DF http://diy-audio-blog.blogspot.com

4th July 2007, 01:34 PM	#7
siang diyAudio Member Join Date: Sep 2005	thank you all thank you all for the valuable information.

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3rd July 2007, 02:25 PM	#2
siang diyAudio Member Join Date: Sep 2005	I'm also interested in this also but it seems no one has tried both? siang

3rd July 2007, 09:54 PM	#3
Sheldon diyAudio Member Join Date: Dec 2003 Location: San Diego	I've use the Tentlabs supplies and have been very pleased with the results. Both units are high impedance devices, and probably have high enough bandwidth, so should work similarly. One major difference is that the Tentlabs unit is very low dropout. If you have a 5V winding, you can regulate at 5VDC. It looks like the machmat unit requires at least 3 volts higher for the AC input. Sheldon

3rd July 2007, 11:37 PM	#5
Sheldon diyAudio Member Join Date: Dec 2003 Location: San Diego	I think in a PP amp you might be able to use one per pp pair (confirm first), but for SE amps, yes, you need a separate winding and power supply per OP tube or per pair (if parallel). Sheldon

4th July 2007, 06:59 AM	#6
Gerrit Boers diyAudio Member Join Date: May 2007	I used the MachMat VCCS (DC version) because I wanted to use a CRC filter before the regulator. In this case the MacMat was the better choice. At 1.5 amps the VCCS needs an input voltage that is 4V above the output, this means you have to have a serious heatsink. My experiments can be found here: Heater supply part 4 If you want to upgrade the heater supply of an existing amp I think the Tentlabs module would be the preferred choice because of the lower voltage drop.

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