The Reference 6SN7 Thread

[bcowen]

Just wanted to share my latest creation - a dual adapter made for strapping pentodes and hexodes (6J7G, CV1581, 6U7G, 6K8G among many others) -> 6SN7

I have not seen much in the way of wooden adapters, but it sure does look nice so thought I would share.

Also, I wanted to express my gratitude to everyone on here that has been so willing to share so much valuable information in regards to the vast world of tubes - you have all done wonders for the learning curve involved. Without that, I am sure I wouldn't have made it even close to this point yet.

Here it is running a pair of RCA 6J7G tubes



And here it is running a pair of Mullard CV1581 tubes


Amp is a Eufonika H5M for anyone wondering.

Love the look of that adapter. Very nice!!

 

[g0ldl10n]

Love the look of that adapter. Very nice!!

Thanks man! Many of the tubes I run in it like the 6J7G barely fit.. if I would have positioned the sockets 1mm closer to each other I don't think they would have fit

I learned a lot building it though, so the next one I build ill keep that in mind.

Think next up will be one for dual single triodes such as the EBC33/VR55 -> 6SN7

I have, and will always be that person that can live with very ugly setups so long as the SQ justifies it (hence the external PS adapter and wire running to a voltage regulator, which surprisingly you actually can't see in those pictures, running a 6336 output tube), but I must say, there is definitely a certain enjoyment and pleasure you get when the setup is looking its best, which I guess I never really realized until now, lol. So I am definitely going to end up building wooden adapters for all the different tubes I have in rotation because of that.

 

[jonathan c]

Thanks man! Many of the tubes I run in it like the 6J7G barely fit.. if I would have positioned the sockets 1mm closer to each other I don't think they would have fit

I learned a lot building it though, so the next one I build ill keep that in mind.

Think next up will be one for dual single triodes such as the EBC33/VR55 -> 6SN7

I have, and will always be that person that can live with very ugly setups so long as the SQ justifies it (hence the external PS adapter and wire running to a voltage regulator, which surprisingly you actually can't see in those pictures, running a 6336 output tube), but I must say, there is definitely a certain enjoyment and pleasure you get when the setup is looking its best, which I guess I never really realized until now, lol. So I am definitely going to end up building wooden adapters for all the different tubes I have in rotation because of that.

Do you line the insides of the adapters to ward off EMI / RFI etc ? …

 

[g0ldl10n]

Do you line the insides of the adapters to ward off EMI / RFI etc ? …

That adapter, I did not but that's a good idea! So far though, thankfully it's super quiet.. think I will do this on the others tho.

 

[jonathan c]

That adapter, I did not but that's a good idea! So far though, thankfully it's super quiet.. think I will do this on the others tho.

I’m not an engineer by trade…just musing also that lining of sorts might protect the inside wood from heat …

 

[LobalWarming]

I’m not an engineer by trade…just musing also that lining of sorts might protect the inside wood from heat …

Heat? Make adapters from thick vacuum tube glass.

 

[TLO]

Just wanted to share my latest creation - a dual adapter made for strapping pentodes and hexodes (6J7G, CV1581, 6U7G, 6K8G among many others) -> 6SN7

I have not seen much in the way of wooden adapters, but it sure does look nice so thought I would share.

Also, I wanted to express my gratitude to everyone on here that has been so willing to share so much valuable information in regards to the vast world of tubes - you have all done wonders for the learning curve involved. Without that, I am sure I wouldn't have made it even close to this point yet.

Here it is running a pair of RCA 6J7G tubes



And here it is running a pair of Mullard CV1581 tubes


Amp is a Eufonika H5M for anyone wondering.

This is what I will call Tube Rolling 2.0...LOL

 

[bcowen]

That adapter, I did not but that's a good idea! So far though, thankfully it's super quiet.. think I will do this on the others tho.

I used an 18 gauge copper plate on top (mostly for structure) and then added copper tape around the outside (mostly for appearance) on this 6J5 -> 6SN7 adapter. The box itself is black plastic. Don't know if it helped sonically from the noise rejection standpoint 'cause I didn't try it "naked" first.

Original plan was to have the brackets inside the box instead of on top so that only the sockets protruded through the plate, but there wasn't enough vertical clearance inside the box to do that without cramming the wiring into a wad.

 

[ARCXENOS]

I have been looking at vintage testers on ebay for quite a bit, and it seems like in general (correct me if I am wrong) :

- Most of them are labelled for parts (and even just for parts, they cost alot!)
- A good chunk of them requires recalibration and/or have some weird anomaly that requires restoration works
- Missing / Damaged manuals and sheets seem to expected due to age
- Those that claim that they are in good perfect working order cost a good chunk more

I think I have decided to skip the guessing game, and choose to go for a "Buy Once Cry Once" approach.

I am looking at the MaxiPreAmp II now, is that anything wrong I should know about? I've sent an email asking them about ECC32 and 6J5s, hopefully they are compatible with the tester

 

[Mr Trev]

Heat? Make adapters from thick vacuum tube glass.

Pyrex FTW

 

[bcowen]

I have been looking at vintage testers on ebay for quite a bit, and it seems like in general (correct me if I am wrong) :

- Most of them are labelled for parts (and even just for parts, they cost alot!)
- A good chunk of them requires recalibration and/or have some weird anomaly that requires restoration works
- Missing / Damaged manuals and sheets seem to expected due to age
- Those that claim that they are in good perfect working order cost a good chunk more

I think I have decided to skip the guessing game, and choose to go for a "Buy Once Cry Once" approach.

I am looking at the MaxiPreAmp II now, is that anything wrong I should know about? I've sent an email asking them about ECC32 and 6J5s, hopefully they are compatible with the tester

There are a growing number of new testers being made from several different manufacturers. Go back 20 years and your only (somewhat) economical choice was one of the vintage testers. I used to buy/refurb/resell vintage testers on a regular basis, but just haven't had the time (or motivation) to do it for the last several years. I'm a bit biased as I love my old Hickoks, but if I were to start from scratch today I'd (personally) go with a newly manufactured unit. Modern materials, modern tolerances, easy to calibrate, warranty, parts availability if something dies, etc etc. I don't have any direct experience with the Maxi Matcher(s) (assume that's what you're referring to?), but they look to be very nicely made.

From my experience, a few added comments to your bullet points:

- Most of them are labelled for parts (and even just for parts, they cost alot!)

Makes it easy to deny any liability for a non-working unit. "I sold it as parts only, and never claimed it actually worked."

- A good chunk of them requires recalibration and/or have some weird anomaly that requires restoration works

Change that from 'good chunk' to ALL. Unless the tester has already been thoroughly refurbished by someone that knows what they're doing, the capacitors (at bare minimum) are going to be either dead or way out of spec. 25 - 30 years is a good lifetime for a modern electrolytic capacitor, and the electrolytics in these vintage testers are 45+ years old now and had a shorter lifespan to begin with.

- Missing / Damaged manuals and sheets seem to expected due to age

If the tester was produced in good quantity back in the day, chances are good that documentation is available online. BAMA is a great resource and a good place to look to see what's available for any particular vintage tester:

https://bama.edebris.com/

- Those that claim that they are in good perfect working order cost a good chunk more

The operative word here is 'claim.' Probably half of the testers I've purchased that were claimed to be in perfect working order were anything but. The biggest problem here is the parts. Easy enough to find replacement resistors and capacitors and such, but if you have a dead meter, it can get interesting trying to find a suitable replacement. Broken rotary switch? Same thing. Fried transformer? You just got a boat anchor. Not only will you not find a replacement (short of buying another machine as a donor), but I can guarantee you'll have the time of your life getting it installed.

 

[Isaacc7]

Just wanted to share my latest creation - a dual adapter made for strapping pentodes and hexodes (6J7G, CV1581, 6U7G, 6K8G among many others) -> 6SN7

I have not seen much in the way of wooden adapters, but it sure does look nice so thought I would share.

Also, I wanted to express my gratitude to everyone on here that has been so willing to share so much valuable information in regards to the vast world of tubes - you have all done wonders for the learning curve involved. Without that, I am sure I wouldn't have made it even close to this point yet.

Here it is running a pair of RCA 6J7G tubes



And here it is running a pair of Mullard CV1581 tubes


Amp is a Eufonika H5M for anyone wondering.

Fun Fact, the 7c5 is just a 6j7 internally wired as a triode. Even though the 6c5 is (pretty much) the same as a 6j5 it keeps all the extra elements off the 6j7. I love the sound of the Cossor 6c5g but I’m not a fan of the price, especially since I need 4 at a time. I have started to explore the world of triode strapped pentodes myself. Since I use external supplies for the heaters I have been able to get 12v, 4v, and even 20v tubes. Just got in some MOV KTZ41 to use in the same adapters as the 8d2. I’m posting over in the 6j5 thread as I start trying them out.

 

[leftside]

I thoroughly recommend getting a modern tester. Especially if you have quite a few tubes. I just wish I'd have purchased both of mine earlier. Both have paid for themselves now.

 

[g0ldl10n]

There are a growing number of new testers being made from several different manufacturers. Go back 20 years and your only (somewhat) economical choice was one of the vintage testers. I used to buy/refurb/resell vintage testers on a regular basis, but just haven't had the time (or motivation) to do it for the last several years. I'm a bit biased as I love my old Hickoks, but if I were to start from scratch today I'd (personally) go with a newly manufactured unit. Modern materials, modern tolerances, easy to calibrate, warranty, parts availability if something dies, etc etc. I don't have any direct experience with the Maxi Matcher(s) (assume that's what you're referring to?), but they look to be very nicely made.

From my experience, a few added comments to your bullet points:

- Most of them are labelled for parts (and even just for parts, they cost alot!)

Makes it easy to deny any liability for a non-working unit. "I sold it as parts only, and never claimed it actually worked."

- A good chunk of them requires recalibration and/or have some weird anomaly that requires restoration works

Change that from 'good chunk' to ALL. Unless the tester has already been thoroughly refurbished by someone that knows what they're doing, the capacitors (at bare minimum) are going to be either dead or way out of spec. 25 - 30 years is a good lifetime for a modern electrolytic capacitor, and the electrolytics in these vintage testers are 45+ years old now and had a shorter lifespan to begin with.

- Missing / Damaged manuals and sheets seem to expected due to age

If the tester was produced in good quantity back in the day, chances are good that documentation is available online. BAMA is a great resource and a good place to look to see what's available for any particular vintage tester:

https://bama.edebris.com/

- Those that claim that they are in good perfect working order cost a good chunk more

The operative word here is 'claim.' Probably half of the testers I've purchased that were claimed to be in perfect working order were anything but. The biggest problem here is the parts. Easy enough to find replacement resistors and capacitors and such, but if you have a dead meter, it can get interesting trying to find a suitable replacement. Broken rotary switch? Same thing. Fried transformer? You just got a boat anchor. Not only will you not find a replacement (short of buying another machine as a donor), but I can guarantee you'll have the time of your life getting it installed.

Hey man, great info - got a question about the life span of caps in a vintage unit that was never used. If one came across a vintage tester that was actually "NOS", would those caps still need replaced?

 

[bcowen]

Hey man, great info - got a question about the life span of caps in a vintage unit that was never used. If one came across a vintage tester that was actually "NOS", would those caps still need replaced?

Quite likely. It's the loss of the electrolyte fluid (drying up, evaporating, leaking, etc) that normally causes their demise, and that process occurs regardless of usage.