Topic on tubes

Schematics, layouts & other technical mumbo jumbo.

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Radiotron
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Re: Topic on tubes

Post by Radiotron »

Interesting choice, never considered those for some reason, is that a Bax with mid control in those Top 50’s?

Here’s the circuit idea for the next weekend build. All octal 5F10 with some upgrades and added grid-leak input.

Image
Last edited by Radiotron on Thu Jan 26, 2017 10:45 pm, edited 1 time in total.
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Dr Tony Balls
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Re: Topic on tubes

Post by Dr Tony Balls »

Radiotron wrote:Interesting choice, never considered those for some reason, is that a Bax with mid control in those Top 50’s?
Yeah but more interestingly (to me anyway) is that its a bax with an LTPI and not a whole lot else. Those two things are a pretty rare combo and the simplicity of it pretty awesome. I'm about to build myself a 100W version of the same thing for bass.
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Doc Holliday
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Re: Topic on tubes

Post by Doc Holliday »

The Harvard looks ace! I have a 6SL7 in the second position (V2) on the GA-6.
Recently picked up a NOS Jan military version for it.
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Doc Holliday
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Re: Topic on tubes

Post by Doc Holliday »

Image

Here's that brimar next to a USSR tube. It doesn't have the same internal construction from what I can see and carries a date code with the BVA made in England but I'm still unsure ...
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Radiotron
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Re: Topic on tubes

Post by Radiotron »

I really wanted to do an all octal build again, I have a box full of 6SL7’s here collecting dust, such a waste.
I probably have 10 lifetimes worth of tubes sitting here, which is a bit crazy really :smashed:

Anyways, I hope to do some more tube testing (µ-tracer) over the weekend so I can share some test results of the different 6V6’s I have here to add to the excellent write-up Waveclipper did, see if there’s actually is a connection between the test data and sonic characteristics.
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PlumCrazy
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Re: Topic on tubes

Post by PlumCrazy »

I was lucky enough to stumble upon an Amplitrex AT-1000 for a decent price. Started matching my own from my larger collection. Here's my quick overview of 6V6s:
RCAs are a nice warm tube with nice breakup - I don't notice a large difference between gray and black plates.
The 70s-80s Sylvanias/Philips are brighter - remind me a bit of EL84s
The older Sylvanias are a nice tube - not as bright - using a pair in my Fender Bassman 20 and that thing has 420v on the plates. No problems after a year.
I think the 60s GEs are a sleeper tube. They are solid with a mid-rangy compression that I really like.
I have a CBS/Hytron in my 5F1 Champ clone and the thing is has a woody midrange that works great with a LP and a Fuzz Face. The bass and treble are in the backseat but they work with this setup.
I had some Bendix 5992s for a while and they are a great tube - they had a bit more headroom (kinda like the JJ 6V6S) and were nice and round. The build quality is incredible - tax $ thrown at cold war fears makes for great tone.
The Raytheons are another sleeper - a good tube for single ended amp. A bit harder to find in the amount to match up pairs.
I had some Brimars for a while and wasn't really impressed with them - not for the price they wanted for them.

6V6s are my favorite tube - they are nice because if you have a way to match them, or only need singles they can still be had for a decent price. Don't buy NOS - it's a waste of money. 80-90% tested from a reputable seller who knows what they are doing (read - not calling them matched because they look the same) is a good way to go. You can also really impact the sound of them depending on how you bias them up. Just throwing them in an amp and trying to make an assessment without really knowing what you are doing is not a good way to test the sound.
http://www.plumcrazyfx.com
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Doc Holliday
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Re: Topic on tubes

Post by Doc Holliday »

Thanks for the input Kaare! Good reading!
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waveclipper
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Re: Topic on tubes

Post by waveclipper »

Doc Holliday wrote:Image

Here's that brimar next to a USSR tube. It doesn't have the same internal construction from what I can see and carries a date code with the BVA made in England but I'm still unsure ...
That looks like a cleaner version of my (what I think is Russian) one is. I read in a few different places that Brimar re-labelled Russian tubes during the 70s & 80s and put the BVA stamp on it to get them in to the US.
The glass is completely opaque compared to the slightly translucent British Brimar, it has a round getter at the bottom compared to the British square getter (I just can't get a proper picture with my crappy camera) and it has a newer 'Brimar' logo on the glass rather than the British one having '6v6gt' in an octagonal surround, and the British one has the Brimar logo on the tube base.

Russian (probably!) like yours with the 'made in England BVA' stamp on the glass on the right -
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I don't know for absolute certain if it's Russian made but the original British Brimar sounds like Led Zep I and the dubious one sounds like Justin fuckin Bieber in comparison - it works but it's just totally limp wristed and dull. The real one is unlike any American 6v6 to my ears, an aggressive throaty open sound with accentuated high mids/highs - sounds a huge sackful of greasy freshly dropped nuts (to go all gearpagey on ya :smashed:)
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Doc Holliday
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Re: Topic on tubes

Post by Doc Holliday »

Sounds like an crazy good tube. Which leads me to believe mine is a Russian. I had heard the brimar is like an El34 in a 6v6 bottle. Shame I can't pick up a matched pair for under £70
Would you say the brimars are a dark tube? I find ken rad and GE to be brighter than RCA and have good clarity even with drive. Prefer the Ken Rad though.
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HorseyBoy
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Re: Topic on tubes

Post by HorseyBoy »

Image

Love these original (rebranded) Silvertone tubes (from a 1482 for sale on Reverb): some made in the USA, some in Holland.
One of these days I'm going to get me some Australian-made Phillips and Mullard tubes, just for the sake of national pride. Both had factories here back in the good old days.
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