3B7 Loctal DHT

Klimon · 3rd March 2009, 06:50 AM

Looking for curves / operation points / testimonies about this tube.

Thanks!

Simon

revintage · 3rd March 2009, 10:08 AM

http://frank.pocnet.net/sheets/127/3/3B7.pdf

Curves look nice from 2-3mA and up. Ra should be in the ballpark of 10kohm.

Why not parallell the halves for a transformer coupled (4:1) SE pre?

andyjevans · 3rd March 2009, 10:20 AM

I tried using the 3B7 but found it harsh. I didn't scope it, so there's a real possibility that it was oscillating and needed a bigger grid stopper. So if you have a go at listening to one, put a decent size grid stopper on it.

andy

revintage · 3rd March 2009, 10:22 AM

Thanks Andy,

Is there a DHT you haven´t tried

?

By the way, are they easy to find?

andyjevans · 3rd March 2009, 11:18 AM

Is there a DHT I haven't tried?

Yes - megabuck ones like the 50, and esoteric new production.

Also I haven't yet tried out the European ones I've been buying - RE034, 074, 084, 134

But seriously, there were loads of different DHTs made. I've probably tried most of the popular ones which were about in large quantities.

I think the 3B7 is quite easy to get - dealers should have them.

andy

Klimon · 4th March 2009, 05:48 AM

Interesting, thanks!

Simon

nafunga · 4th March 2009, 09:21 AM

Regarding DHT small signal types available in the UK, the LP2, PM2A etc, range of 2v filament valves are readily available from the usual sources i.e, Colomor and Langrex. The types mentioned were originally designed for audio output stages (approx. 0.1W) but make very good drivers for larger rated types. I use them to drive VT-25's etc. They work well.

Regards,

David.

3rd March 2009, 06:50 AM	#1
Klimon diyAudio Member Join Date: Apr 2005 Location: Leuven	3B7 Loctal DHT Looking for curves / operation points / testimonies about this tube. Thanks! Simon

3rd March 2009, 10:08 AM	#2
revintage diyAudio Member Join Date: May 2007 Location: Eskilstuna, Sweden	http://frank.pocnet.net/sheets/127/3/3B7.pdf Curves look nice from 2-3mA and up. Ra should be in the ballpark of 10kohm. Why not parallell the halves for a transformer coupled (4:1) SE pre? __________________ Brgds Lars

3rd March 2009, 10:22 AM	#4
revintage diyAudio Member Join Date: May 2007 Location: Eskilstuna, Sweden	Thanks Andy, Is there a DHT you haven´t tried ? By the way, are they easy to find? __________________ Brgds Lars

4th March 2009, 09:21 AM	#7
nafunga diyAudio Member Join Date: Jul 2005 Location: Whitstable , Kent. UK	DHT Regarding DHT small signal types available in the UK, the LP2, PM2A etc, range of 2v filament valves are readily available from the usual sources i.e, Colomor and Langrex. The types mentioned were originally designed for audio output stages (approx. 0.1W) but make very good drivers for larger rated types. I use them to drive VT-25's etc. They work well. Regards, David.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

3rd March 2009, 10:20 AM	#3
andyjevans diyAudio Member Join Date: Sep 2003 Location: London	I tried using the 3B7 but found it harsh. I didn't scope it, so there's a real possibility that it was oscillating and needed a bigger grid stopper. So if you have a go at listening to one, put a decent size grid stopper on it. andy

3rd March 2009, 11:18 AM	#5
andyjevans diyAudio Member Join Date: Sep 2003 Location: London	Is there a DHT I haven't tried? Yes - megabuck ones like the 50, and esoteric new production. Also I haven't yet tried out the European ones I've been buying - RE034, 074, 084, 134 But seriously, there were loads of different DHTs made. I've probably tried most of the popular ones which were about in large quantities. I think the 3B7 is quite easy to get - dealers should have them. andy

4th March 2009, 05:48 AM	#6
Klimon diyAudio Member Join Date: Apr 2005 Location: Leuven	Interesting, thanks! Simon

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Are there any loctal PC sockets?	Joku	Tubes / Valves	2	18th May 2009 01:55 AM
Is there a LOCTAL equiv to a 6V6?	grhughes	Tubes / Valves	16	12th March 2009 11:53 PM
Loctal Rectifiers	dsavitsk	Tubes / Valves	2	30th January 2008 09:24 PM
Loctal 6SN7?	pftrvlr	Tubes / Valves	11	21st January 2008 03:45 PM
PCB Mount Loctal Socket?	dsavitsk	Tubes / Valves	0	9th March 2007 11:17 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read