Valve production is starting back up

IMG_9452.GIF I ordered and installed 5751 preamp tubes for my Fender Hot Rod Deluxe. The volume is out of control with a 12AX7 in V1. The volume was just as wild with the 5751 tube. I put a 12AT7 in VI and now it close to normal. I do have an over priced old vintage 5751 on the way. I'll try it for shLts and giggles. Point of the tail is the two tubes are so close on specs it doesn't matter.
 
syscokid said:
Is the GZ34 the same as a 5AR4?

My Allen Amp Sweet Spot, which is sort of based on a Blackface Princeton, has a Sovtek 5AR4 that came with the amp kit over 8 years ago.
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A 5AR4 "was" a "direct replacement" for the GZ34, so made by different manufacturers. I think the 5AR4 was originally US manufactured, though now (current production) the GZ34 & 5AR4 are recognized as the same tube. Originally, the 5AR4 dropped a tiny bit more voltage & sagged a tiny bit more than the GZ34 (slightly higher internal resistance), though you probably wouldn't notice it in an amp. Cheers
 
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kevinpaul said:
View attachment 17431 Point of the tail is the two tubes are so close on specs it doesn't matter.
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The specs (originally) are the same in all regards except for the amplification factor (voltage gain), 100 for the 12AX7,,, 70 for the 5751. I've only ever used NOS types, I don't put much stock in new production pre amp tubes spec'ing properly. I've only used them in older type amp designs where they've worked well. Let us know how the NOS type performs. Cheers
 
DonP said:
English valve manufacturer Brimar is being revived. Back in the day they were responsible for some of the best valves on the market - right up there with Mullard.

Anyway, there is a factory full of equipment that needs some serious TLC, and they are asking for volunteers to help restore it to working condition. And yes, of course I have offered. They are a hundred miles away, but I can probably do a day each week.

Great British Valve Project

This is going to be exciting, and I hope something comes of it.
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!!! Too Freak'n Cool !!!
I'd like to suggest a name for one of their tubes - The British Spitfire...
Either a tube or maybe an amp they can make and sell ;)
 
RVA said:
Don, how is this re-start going? Did you ever make a visit there?
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I made a visit, but it turned out they didn't need my help - they already had more than they could deal with. They have a decent range for guitar amps though. Obviously the 12AX7 and the ECC81 to 83 for the input section. And EL34 and KT66/88 for big amps. EL84 completes the picture for smaller practice amps. They have a bunch of other stuff too.

I can't say yet if this is viable in the long term, but I'm hoping.
 
DonP said:
I made a visit, but it turned out they didn't need my help - they already had more than they could deal with. They have a decent range for guitar amps though. Obviously the 12AX7 and the ECC81 to 83 for the input section. And EL34 and KT66/88 for big amps. EL84 completes the picture for smaller practice amps. They have a bunch of other stuff too.

I can't say yet if this is viable in the long term, but I'm hoping.
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Cool. It must have been an interesting trip. I will keep an eye out and try the product of the opportunity presents itself
 
Gahr said:
Not entirely on topic, but why do Brits tend to use the term «valve» while Americans use «tube»?
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vacuum tube
n.
an electron tube from which the air has been evacuated to the highest possible degree

vacuum valve
n.
Brit. VACUUM TUBE
 
Good to see they are making progress. I recently got a couple more '60s NOS Brimar CV4004 ECC83's, slated for use in my upcoming NOS rebuild of one of my 50 watters, period correct Iskra & Piher resistors, mustard caps etc which I'll post details of. Hopefully my phone can post a "fair" quality couple of pics.15443890223814029271062785646742.jpg
On an Amplitrex tester this one is showing mA 1.3/1.3, gm 1800/1800.15443893182848958549382303708661.jpg
This one is showing mA 1.3/1.4, gm 1700/1800.
Also for use in the amp is a NOS (1974) 163 series Mullard ECC831544389716670457542361529629677.jpg
The etched Blackburn codes can be seen. This is a hot valve, showing mA 1.6/1.7, gm 2000/2000. Also for use in this amp is a (1973) Mullard (7 notch) f32 GZ341544390137415266494148227728917.jpg
Again the etched Blackburn codes can be seen. I have a NOS duet of Mullard xf2 EL34's & another 163 ECC83 on the way. Sorry for the derail, I did want to show the '60s Brimar CV4004's & got carried away. Really hoping that when they get to production they can rival the Brimar of old. Cheers
 
Catmandue said:
vacuum tube
n.
an electron tube from which the air has been evacuated to the highest possible degree

vacuum valve
n.
Brit. VACUUM TUBE
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Here in Oz they are referred to as a "valve" too. They are called valves because they control the flow of electrons, so theoretically act as a valve.
Kinda surprised they didn't want your help in some way Don, you are very knowledgeable. Hopefully they have some on the team that were involved in valve production back in the day. I can imagine that quite a bit of technical production knowledge has been lost to the sands of time. Cheers
 
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