[martyo]

Thanks Larry!

[Mr Peabody]

Greyhound was nice enough to send me a few sets of 6CG7 tubes to try and I thought I'd share some results.  I rolled tubes in the preamp.

I have AVA FET preamp & 400R driving Revel F52's and a T+A CD Player.

Tung Sols; I did not like them, overly warm, very rolled off with soft bass response.

Mazda; were pretty good, excelled in high frequencies that I thought tonally accurate, grain free and easy to listen to while being extended.  This tube gave me the impression of being very fast, meaning you could hear between strikes of fast drums and between notes of guitars very well.  Seemed to me although not lacking in bass the bass line was sometimes buried.

RCA Black Plates; These were very nice, extended highs, full bass that remained defined a natural warm midrange with good presence.

Sylvania Gray Plates; A hard choice of favorite between these and the RCA-BP but in the end I preferred the Sylvania.  The Sylvania is a very dynamic sounding tube, good presence in the midrange, the bass hits good yet very controlled.  The high end is decent but not as foward as the RCA. 

[avahifi]

I picked up a couple of 9-pin to 8-pin adapter sockets so we could play with 6SN7 tubes in our tube and hybrid preamps and DACs.  They were direct from China and only cost about $15 each.  You have to run with the covers off of course as 6SN7 tubes are much taller, even without the added height of the adapter sockets.

However there is one catch.  The adapters are wired assuming that pin 9 is wired as useful for some 9-pin tubes as a heater supply tap.  Our audio boards do not use the connection to pin 9 so as is, no heater supply for 6SN7 tubes with the adapter right out of the box.

There is a pretty easy to do work around if you are handy with a solder pencil.  All you need is a short jumper wire from pin 9 to pin 5 of the tube sockets.  This can be done on the top side of the mother board wrapped neatly around the base of the tube socket and tucked in so hardly visible.

Then you can try new or old 6SN7 tubes all you want.  We think new production EH6SN7 tubes work pretty well, and an old set of used GE6SN7 tubes even are better yet.

If you are not up to the necessary tube socket wiring work, return your AVA preamp to us and we will do it free of charge for you, except for shipping cost.

Best regards,

Frank Van Alstine

[Mr Peabody]

Unless the 6N7 was quite a bit better than 6CG7 I don't think I'd like the top off look

This is actually the first tube rolling I've done and not sure I would have tried it if the tubes weren't lended to me.  It was a good experience though.

Any idea what drives the cost of tubes?  Rarity, performance etc.?  I shouldn't keep saying anything but the Sylvania were really good and look to be one of the cheapest options.

[dminches]

You don't need to run it with the top off if you modify the cover:

[stephennic]

Hi Greyhound fan and others,

Which do you prefer sonically the RCA clear tops or RCA black/greay plate? What are there sonic traits?

Cheers

Steve.

[mrlittlejeans]

I ordered a pair of RCA clear tops and a pair of Tung-Sols which should be here in the next week or so.  Both will be used in a T8+ preamp over the next few weeks.  I'll post my impressions once the tubes have broken in and I've had a chance to listen to them a bit.

[Mr Peabody]

I hope the Tung Sol and RCA aren't going in the same preamp at the same time, I found them to be quite different from one another.  In my gear I personally did not like the Tung Sol, I can't think of a single thing I liked about them.

I've only heard the RCA Black and I found them to be a full sound with extended highs and ample bass, good detail overall.

[mrlittlejeans]

heh.  No.  They won't be in the T8 at the same time. 

[stephennic]

This thread is titled 6CG7 tube reviews.....nothing about 12AT7 clear tops.  Back on topic:

The 6CG7 black plate US MADE Raytheon is a very hard tube to find, most Raytheons are the Japanese version.  I like the Ray B.P. put them back in the Ultra preamp this week and the one thing they do in my system is move the sound plane to the front of the speakers, not quite as extended on the top end, but a detailed clear sound with zero fatigue.  I like the depth of the clear tops, but the clarity of the Raytheons.

Hi all,

What do the japanese version of the Raytheons 6cg7 sound like?, the ones you like the most are they the american version?.

Cheers

Steve.

[SP2002]

Hi all,

This is my first post on this forum and it is a call for help. I just got a pair of RCA 6CG7s to replace the 6N1Ps in my T8 and I want to scream! The 6CG7s simply will not go in to the tube sockets. The pins line up with the socket holes, they match perfectly with the pins on the 6N1Ps. I keep pushing, straight down and side to side. It's almost as if the individual pins are too fat for the individual sockets. I'm afraid of breaking the circuit board as I watch it bending. I'm not deep in to this hobby but I've replaced tubes before and I never saw anything like this. Is there some sort of trick to this thing?

Thanks

[martyo]

Hi all,

This is my first post on this forum and it is a call for help. I just got a pair of RCA 6CG7s to replace the 6N1Ps in my T8 and I want to scream! The 6CG7s simply will not go in to the tube sockets. The pins line up with the socket holes, they match perfectly with the pins on the 6N1Ps. I keep pushing, straight down and side to side. It's almost as if the individual pins are too fat for the individual sockets. I'm afraid of breaking the circuit board as I watch it bending. I'm not deep in to this hobby but I've replaced tubes before and I never saw anything like this. Is there some sort of trick to this thing?

Thanks

Welcome. I have a T8 and at one time rolled some RCA cleartops and they fit fine. I would suspect the tubes. Everything has a tolerance and if the +/- of the diameters, the Od of the pins and the Id of the socket, was exceeded, could be that is the issue. I'd check the pin diameters with some calipers. Good luck.

[avahifi]

The tube sockets we generally use do have a very tight fit on purpose to make sure there are great long term contacts with the tube pins.

Usually we simply just wiggle the tube slightly from side to side while pushing it down into place.  This is hardest to do here when the sockets are first used.  With each replacement, it will get easier.  If we have a particularly difficult fit, we use a shot of Caig Labs Deoxit D5 spray into the socket to lubricate it a bit.

Frank

[SP2002]

Thanks for the suggestions guys. Looks like I'll try the deoxit route. And THANK YOU Frank for great products!

[dminches]

You may also want to get some socket savers which will help straighten out the pins.

[trebejo]

I use the tube-pulling task as an opportunity to meditate.

Patience will be required.

A steady hand will be required.

Heat some water, fill the teapot and put some leaves in there to brew.

Breathe deep. Now exhale. Now go to the tube unit. Now gently pull the tube, and slowly, steadily increase the pulling strength and oscillation. The oscillation should max out at about a degree or so.

After some time, you'll feel the tube start to make progress. Continue to pull with the same strength and oscillation until the tube comes out.

Now pour the tea and smile at your tube.

Now go back to the tube unit and start to work on the next tube...

btw where is the audiophile tube-pulling device that consists of two platforms that separate themselves very slowly thus ensuring that the tensile strain on all pins does not exceed 0.001% THD and costs $3,000? Frank, the AVA tube-puller could be the big break you've been waiting for!

[SP2002]

THANKS TO ALL for the helpful suggestions. Success at last! Time to sit back and listen. THANKS AGAIN!