Advice on a new tube buffer

[ginetto61]

Again, this board is supposed to be for discussion of new, commercially available, gear that is considered to be a "good value".
I'll try to send you a private message sometime but I'm pretty busy trying to build an amp right now.

Hi ! sorry and message received
Just hope the the thread will not die because i am still interested in a commercial solution.
I wonder if the thread starter or any other member as found anything good
If a really good commercial buffer do exist i would jump on it immediately
So i will be waiting for advice in the background
I have come to the conclusion that i am not quite ready and enough free to take the solder
for now

 

[sqlsavior]

I had an early version of the Yaqin CD3 tube buffer (I think - it had the old-fashioned tube shields with the springs inside for actual EMI shielding with anti-microphonic properties, not the new guards that look like shoulder pads or whatever ). I wanted to try one to tame harsh CDs. While I believe it's possible they could take some of the edge off, the Yaqin really didn't seem to change the sound much - I had it in the tape loop to switch it in and out of circuit. I've since concluded that attempting to tame harsh CDs is best done with a circular file (my father's term for the wastebasket).

As for experimenting with tubes affecting the sound, I think a preamp or a power amp would be more revealing of differences, and would make a bigger difference in the first place than a tube buffer. I have even read of tubes that are just there to look good - nothing goes through them!

 

[ginetto61]

I had an early version of the Yaqin CD3 tube buffer ... I wanted to try one to tame harsh CDs. While I believe it's possible they could take some of the edge off, the Yaqin really didn't seem to change the sound much - I had it in the tape loop to switch it in and out of circuit. I've since concluded that attempting to tame harsh CDs is best done with a circular file (my father's term for the wastebasket).

Hi ! i do not know if distortion can be classified as a kind of harshness ... anyway i had a cd from Oasis "definitely maybe " While the songs were quite excellent the recording level was too high and the sounds distorted IMHO of course
At the point of being painful in my humble system. Then i took it to a friend's house where he had a much nicer system with a tube preamp. And i have to say that sound was way more tolerable ... almost nice
My point is that especially with digital sources tubes can provide something beneficial. What is painful with solid state with tubes becomes tolerable and even nice.
Of course the high distortion was still very evident ... and yet i liked the sound much better.
I do not know why that cd was recorded so loud ... Another friend has a dac that shows when distortion is present in the signal. The distortion red led was almost always on

... As for experimenting with tubes affecting the sound, I think a preamp or a power amp would be more revealing of differences, and would make a bigger difference in the first place than a tube buffer. I have even read of tubes that are just there to look good - nothing goes through them!

personally i like minimalist designs. And tube designs are minimalistic by nature. Some single ended power amp are made out of a single power tube
I do not know why solid state instead is so complex. I know at least one solid state line preamp made out of a single mosfet. It sounds really good. I do not know why SS audio designers instead take the complexity route ... not all ... most of them

 

[dajack761]

I've been over this with you on several previous occasions. Yet, you keep asking the exact same question so I'll try to explain it one more time.

Converting an anode follower circuit (like the FX) to a cathode follower circuit (a buffer) is not that difficult but it involves more than simply connecting the cathode to the output. There are a few other changes involved.

In previous posts I've linked an excellent DIY site that shows a schematic, parts list, tools list and provides extremely detailed, step-by-step instructions on how to build it. It even allows the use of the 12BH7, which you seem to want to try. It could be built in a metal chassis or even, like a breadboard, on a piece of wood using sockets and connectors that don't require soldering. I even provided links to the sockets and connectors.

Here it is again: https://wtfamps.com/muchedumbre-3/

Yes, it involves voltages that are higher than the FX has but that's a good thing. As I discovered when I breadboarded the FX circuit, the low voltages used are a serious limitation. The sound is much better when the tube is operated at "normal" voltages, for which it was designed. What a surprise!

While you're building something, there is no voltage present. After it's built, it will need to be tested but, if you're capable of keeping your fingers on the insulated plastic grips of a multimeter, there is no danger. You take the same risk when you plug a lamp into a wall socket. Presumably, you don't get shocked, which indicates that you're capable of holding the insulated portion of the plug without touching the metal prongs.

After I posted that link you said you would prefer to build a kit rather than build something from scratch. So, I posted a link to a buffer kit designed and sold by a highly respected audio "guru" that runs off the same type of wall wart power supply as the FX. I'm sure it also comes with very detailed instructions. The same designer also offers several other buffer kits.

Here it is again: https://glass-ware.stores.yahoo.net/tubu.html

Yet, you seem to be intent on taking a circuit board that is designed as a preamp and hacking it apart to create a buffer. I've tried to point out downsides and limitations of trying to modify a circuit board. They are not made to be modified. Yet, you persist . . .

There is a recent thread over on DIY Audio in which the poster converts something similar to the FX to a buffer. He uses one of the generic schematics to show the changes. The board pictured doesn't seem to be the same as the FX. I don't know know exactly where it came from. It looks like it may have been sold as a board only, and was never installed in a finished preamp like the FX. Here's a link:

https://www.diyaudio.com/forums/tubes-valves/361957-6j1-buffer-conversion.html?

The problem with this approach is that, even if you successfully alter the circuit, you're still running the tubes at ridiculously low voltages so it will still be compromised.

The two examples I suggested earlier will, undoubtedly, yield better results and they are not difficult to build.

Hi FlaCharlie,
Thanks for reposting the information and links. I’ve been away from the forum for a bit and probably missed some of the original discussion. I’m going to try building the tube buffer preamp kit. The instructions are quite detailed which should be quite helpful. It looks like it will a fun project!

Thanks,
Dwane

 

[FlaCharlie]

Hi FlaCharlie,
Thanks for reposting the information and links. I’ve been away from the forum for a bit and probably missed some of the original discussion. I’m going to try building the tube buffer preamp kit. The instructions are quite detailed which should be quite helpful. It looks like it will a fun project!

Thanks,
Dwane

Hi Dwane,

Are you building one of the GlassWare kits? Can you post a link to the particular version? Broskie is a widely known "tube guru". Totally legit. If you want to build a kit, he's got it covered.

As I've pointed out several times, many of the units and kits that are sold as "buffers" are actually preamps. The GlassWare kits I linked are true buffers. He also sells preamps and other stuff. I have no experience with them since I like to build from scratch using point to point wiring.

Here's a link to my "Boogie Factor 1626" preamp build:
https://www.audiokarma.org/forums/index.php?threads/1626-preamp-build.931276/

Please post updates on your progress.

 

[dajack761]

Hi Dwane,

Are you building one of the GlassWare kits? Can you post a link to the particular version? Broskie is a widely known "tube guru". Totally legit. If you want to build a kit, he's got it covered.

As I've pointed out several times, many of the units and kits that are sold as "buffers" are actually preamps. The GlassWare kits I linked are true buffers. He also sells preamps and other stuff. I have no experience with them since I like to build from scratch using point to point wiring.

Here's a link to my "Boogie Factor 1626" preamp build:
https://www.audiokarma.org/forums/index.php?threads/1626-preamp-build.931276/

Please post updates on your progress.

Hi FlaCharlie,

I’m going to do the Octal Aikido for onesystem
https://glass-ware.stores.yahoo.net/ocaicafo.html

I’ve wanted to try my hand at building a tube preamp and this one, the MuchedumbreBuffer Preamp looks interesting for a winterproject. found here

https://wtfamps.com/muchedumbre-3/

 

[FlaCharlie]

Hi FlaCharlie,

I’m going to do the Octal Aikido for onesystem
https://glass-ware.stores.yahoo.net/ocaicafo.html

I’ve wanted to try my hand at building a tube preamp and this one, the MuchedumbreBuffer Preamp looks interesting for a winterproject. found here
https://wtfamps.com/muchedumbre-3/
https://wtfamps.com/muchedumbre-3/

If you don't need gain buffers like these are the way to go. I wanted the option of having some gain so the preamp I built does have just a bit, but only if you turn it way up.

The GlassWare kit should be a simple project. While the Muchedumbre will be a bit more involved, the step-by-step instructions are superb.

What tubes will you be using in these? The GlassWare seems to offer a wide array of possibilities.

The Muchedumbre seems to be designed around the 12AU7, although they also mention the option of using 12BH7s. I've never used either in a buffer but I really like the 12BH7. I even built a SET amp using them as output tubes.

 

[dajack761]

If you don't need gain buffers like these are the way to go. I wanted the option of having some gain so the preamp I built does have just a bit, but only if you turn it way up.

The GlassWare kit should be a simple project. While the Muchedumbre will be a bit more involved, the step-by-step instructions are superb.

What tubes will you be using in these? The GlassWare seems to offer a wide array of possibilities.

The Muchedumbre seems to be designed around the 12AU7, although they also mention the option of using 12BH7s. I've never used either in a buffer but I really like the 12BH7. I even built a SET amp using them as output tubes.

I guess I’ll be using 6SN7 tungsol for the tube buffer. When I ordered the kit the invoice said they were sold out, but I’ll check again or maybe find it somewhere else. When I get to the preamp, i’ll probably start with 12AU7 and do some tube rolling when I get it working. I’ll try to spread out the projects out over the winter.

 

[FlaCharlie]

I guess I’ll be using 6SN7 tungsol for the tube buffer. When I ordered the kit the invoice said they were sold out, but I’ll check again or maybe find it somewhere else. When I get to the preamp, i’ll probably start with 12AU7 and do some tube rolling when I get it working. I’ll try to spread out the projects out over the winter.

Both of those are buffers, neither one of them has any gain. So not a preamp, technically.

I don't have any experience with new production tubes, and the Tung Sols may be quite decent. Just realize that they are not the same tube as the NOS ones. Someone bought the rights to use the name, that's all. Unfortunately, many people don't realize this.

NOS 6SN7s can get expensive, I'm sure. The big dealer near me, which has a warehouse with many millions of tubes, lists "generic" 6SN7s for $20. I'm not sure which brands fall into that category but I assume they are NOS. They also have a long list of various brands of 6SN7s in their "NOS Audio" category which are, as expected, not cheap.

But here's a trick if you want cheap NOS . . . use 12SN7s instead. Exact same tube but with a 12.6v heater. The kit you linked lists them as one of the tubes it can use. That same big dealer lists NOS 12SN7s for $5 each! Those new production Tung Sol 6SN7s cost about 5x more.

https://vacuumtubes.net/Prices 12A to 29LE3.htm

 

[dajack761]

Both of those are buffers, neither one of them has any gain. So not a preamp, technically.

I don't have any experience with new production tubes, and the Tung Sols may be quite decent. Just realize that they are not the same tube as the NOS ones. Someone bought the rights to use the name, that's all. Unfortunately, many people don't realize this.

NOS 6SN7s can get expensive, I'm sure. The big dealer near me, which has a warehouse with many millions of tubes, lists "generic" 6SN7s for $20. I'm not sure which brands fall into that category but I assume they are NOS. They also have a long list of various brands of 6SN7s in their "NOS Audio" category which are, as expected, not cheap.

But here's a trick if you want cheap NOS . . . use 12SN7s instead. Exact same tube but with a 12.6v heater. The kit you linked lists them as one of the tubes it can use. That same big dealer lists NOS 12SN7s for $5 each! Those new production Tung Sol 6SN7s cost about 5x more.

https://vacuumtubes.net/Prices 12A to 29LE3.htm

technically, no gain = buffer. Got it.

I didn’t realize that someone bought the naming rights to tungsol. I’ll keep an i out for the NOS just in case. I’ll have to grab a couple of the 12SN7s too and save few bucks in the process. Thanks for the info and the link FlaCharlie!

 

[FlaCharlie]

technically, no gain = buffer. Got it.

I didn’t realize that someone bought the naming rights to tungsol. I’ll keep an i out for the NOS just in case. I’ll have to grab a couple of the 12SN7s too and save few bucks in the process. Thanks for the info and the link FlaCharlie!

Not only Tung Sol. There are also current production tubes branded Mullard, Genelex Gold Lion, Telefunken, and perhaps others.

It's always a good idea to check the prices of the big dealers, like the one I linked. I've found plenty of good deals on eBay too. As always, if you take your time and shop around you'll get a better idea of what's reasonable and what's crazy.

There are a lot of "boutique" dealers out there whose prices are ridiculous. They are marketing geniuses though, just read the poetic descriptions of the tubes they offer. Funny how the "best sounding" and most exotic brands / versions just happen to be whatever they have in stock at the time. The more hype, the less chance that you're going to get a reasonable deal.

Nothing wrong with strong testing used tubes, either.

These days, I mostly buy types that are not commonly used in commercial audio equipment. The 1626, which I used in the preamp I built is a good example. That's one of the advantages of building stuff, you can take advantage of tubes that use different heater voltages, like the 12SN7, or use sockets that are not as common, like loctals.

The loctal base version of the 6SN7, the 7N7, sells for $10 NOS, for example. Loctals, regardless of how they're branded, were all made by Sylvania. The same Sylvania tube with the more common octal base (6SN7) is much more expensive.

 

[hyunh]

I want to build preamp tube 5654, is there a simple normal working schematic with 240v or 300v for that, thank before.

 

[FlaCharlie]

I want to build preamp tube 5654, is there a simple normal working schematic with 240v or 300v for that, thank before.

The 5654 is often used in the little Chinese FX preamps that are the subject of this thread:

FX Audio 6j1 tube preamp - a $31 wonder

I've been spellbound by the tiny FX for several weeks now. If you follow the TPA3116 thread you know I'm not the only one who has fallen for this pint sized beauty. There's so much buzz in the other thread after pairing it with the class d Volt+D I thought it deserved a thread of it's own. The...

audiokarma.org

One of my complaints about the FX is that they run the tubes at voltages that are much lower than normal. I tried them at higher voltage and they sounded much better. So you’re on the right track. I posted two schematics in that thread.

What type of amp are you using? Tube or Class D / SS?

Another issue is that the 5654 (and the other tubes used in the FX and others) are not very well suited for use with Class D and SS amps. And even if you have a tube amp there are better choices.

I’ve been developing a very simple DIY preamp that addresses all of the limitations of the FX and similar commercial offerings. It will be inexpensive and extremely easy to build. You could even build it breadboard style without any soldered connections.

I’ll be posting details on the Tube forum in a day or two.

 

[Oasis8]

Mate has a Yaqin CD3 tube buffer, I changed the input and output caps to Mundorf Supreme Silver/Gold and added drain resistors for him, I also changed the RCA sockets, he has RCA Red Base 5692 tubes in it.