Anyone use SHUGUANG tubes?

[PeanutNore]

Interesting. Mine was branded as Raytheon and came in a Raytheon box, but the plates are the same and the tube has "Yugoslavia" silkscreened on it, so I don't know what else it could be. I bought a Crate Blue Voodoo 120 watt head for $200 a few months ago and the seller included it in the deal. I lucked out, because it also had some Mesa STR-454 6L6GCs in it which are relabeled Winged C's.

[Audiotexan]

Interesting. Mine was branded as Raytheon and came in a Raytheon box, but the plates are the same and the tube has "Yugoslavia" silkscreened on it, so I don't know what else it could be.

Yeah, that's part of why I posted the 1st shot I did, the tubes themselves are actually EI (Nis Yugo) tubes.

A couple of key pointers are: even though they're labelled as being RCA, it's the style of branding label which helps date them, as that's actually 70's-80's RCA styled logo's, and second, we know that Telefunken weren't producing tubes anymore by that point, and third, (and to the best of my knowledge) there are no diamonds on the bottom of any of the real EI variants (at least none that I'm familiar with/personally seen). That's also why I used "diamonds" in quotes, as they're not actual Tele's but came off the same equip.

It's more important to ID tubes by construction (as was previously mentioned in this thread), and IMO you reached a safe conclusion when you assumed them to probably be EI. You might want to check and see if you can see a diamond on the bottom though... as there's always a (albeit slight) chance that it could've been really old stock, that was found and labelled at a later date. Even though I don't recall ever seeing an EI labelled "Raytheon", it wouldn't out of the realm of possibility by any means! In fact, it's almost expected, as rebranding was the norm.

[Chuck H]

Just to add my $.02

Back in the day it was VERY common to see euro tubes rebranded with American company logos. It was less common, but also happened that euro companies would occasionally rebrand for each other. There are guys in the NOS biz that know a lot about who made what for whom and when as well as finite construction details for identification and all era specific. Whew!

I use to get all my golden age preamp tubes as salvage. There was an electronics salvage warehouse in my area that put pulls in boxes roughly labeled for "this to this" tube designations. There was a lot of confusion WRT four digit vs. common US vs. euro tube designations. This actually was a benefit because it meant no one could find anything easily. A forty foot wall stacked with cardboard boxes full of pulled tubes with questionable ID!!! They did have a tube tester on site for culling grossly bad tubes. Other than that it was the cheap price that really made it worth while. I can't begin to guess how many low hour Raytheon, Mullard, RCA, Telefunken, Bugle Boy, and odd other 12ax7 types I purchased for two bucks a piece!!! Of course I had to cull a few because of age. noise or microphonics, but it wasn't half. Even if it had been that would still be four bones per tube to get the same thing guys are paying over fifty bucks a piece for now!!! About twenty bucks at the time I was pulling this off. The snag is that many of the tubes were rebrands or had a lot of the paint rubbed off. I don't really care about that for users so it just put me money ahead for what others were spending a small fortune on. My point?...

In the process I learned a bit about who made what and a whole lot of alternate designations for the same tube types. That's how I know there was so much rebranding going on.

One of my prizes from that era of my life still hasn't been used. A pair of matched Tung Sol 5881's from the golden age in very strong condition. I'm not the type to get all gaga over special tubes but I WILL be listening and hoping to hear a difference when I get to plugging them into something I still have a handful of good preamp tubes too. Most have been used here and there. A couple are old but a couple are still very young (in hours) and sound great. I save them for critical duty like V1 in high gainers where new tubes just can't saddle up.

[Alan0354]

It really pain me to say this. I never believe tube can make that big a difference in the sound. But I was wrong.

I have KMD build and I am experimenting in the Bassman platform. I can switch so the two have the same preamp circuit. My ears must be getting sharper with all the testing in the last few months. I keep hearing a difference. The OD texture are identical as the circuits are the same. But the tonal quality is better. The KMD just have a more open sound and the Bassman have a slight dark horn sound. As I have the A/B input switch to drive one of the two amps and A/B speaker that I can use two different speakers for each amp. I can compare the sound faster and faster. I can just hear the difference between the two amps no matter what speaker I use.

I started switching the power tubes of the Bassman, nothing change. So I took the 3 JJ 12AX7 preamp tubes from the KMD and switch with the Sunghang from the Bassman.................The sound switched!!!. Now the KMD sounds darker and horn like, the Bassman brighter and more open. The sound just switched!!!

The texture did not change, just the tonal quality. It is very obvious and unambiguous. The JJ definitely sounded better. Next, I am going to switch back one by one and see which one is the key.

You guys have any opinion?


EDIT:

I changed the tube one by one. I was expecting the 3rd stage makes the biggest difference as it is saturated, then the 2nd stage and 1st stage should not make any difference.

WRONG!!!

The first stage made 70% of the difference.

But bare in mind my ears are not the sharpest and consistent in the world, but that's how I perceive now.

[loudthud]

How do the gain and bandwidth of the two tubes compare? Are you using a grid stopper? What value?

[PeanutNore]

I ended up with 2 shuguang tubes from pulling them out of the 2 VHT special 6 amps I've owned, and set aside because I was told they were crap. They definitely sounded harsh and brittle in that amp which is a very simple champ type circuit. On a suggestion I tried them in the lead channel of my 6505+ combo where they serve as the last 4 (of 6) gain stages before the tone stack. Huge difference. So much more clarity than the JJs I had in there before.

[Alan0354]

How do the gain and bandwidth of th etwo tubes compare? Are you using a grid stopper? What value?

No, it's a simple stage with 100K plate resistor, 1.5K cathode and 10uF cathode bypass. Then follow with a cathode follower with 100K cathode resistor. Nothing special. Remember this is the first stage, the output is only a few volts.

[Alan0354]

I ended up with 2 shuguang tubes from pulling them out of the 2 VHT special 6 amps I've owned, and set aside because I was told they were crap. They definitely sounded harsh and brittle in that amp which is a very simple champ type circuit. On a suggestion I tried them in the lead channel of my 6505+ combo where they serve as the last 4 (of 6) gain stages before the tone stack. Huge difference. So much more clarity than the JJs I had in there before.

It is darker for me. The more important it's the horn sound that is not good.

[Alan0354]

I have a question, is raising the plate voltage making the 12AX7 sounds brighter? Or am I hearing things? I changed the RC resistors of the +B and make the plate voltage goes at least 30V higher, particular the first tube from 180V to 245V, seems the sound is brighter.

[frus]

I have a question, is raising the plate voltage making the 12AX7 sounds brighter?

sure!

[Chuck H]

Yes, raising the voltage makes a tube brighter. And improves LF. And tightens ALL frequencies produced, to a point... Remember that if you improve gain (in any area or frequency) in a cascade circuit you have a penalty to pay down the road. Better LF in the early stages means there's more LF being overdriven in successive stages. That isn't necessarily a good thing. WRT cascade circuits I tend to prefer higher Vp even on early stages than most, but I also graduate LF pass filtration front toward back in the signal chain. This makes for ample gain while maintaining good note separation IMHE. YMMV.

Many cascade amps have moderate to low-ish Vp on the early stages. This makes for a more midrange heavy character and keeps things "predictable". Phooey!!! Note definition is lost and you end up with the same saturated "blender on frappe" tone as all the rest. Don't be afraid to use a higher Vp on early stages and moderate LF to compensate. Better note separation and overall player control is the reward.

[Alan0354]

Yes, raising the voltage makes a tube brighter. And improves LF. And tightens ALL frequencies produced, to a point... Remember that if you improve gain (in any area or frequency) in a cascade circuit you have a penalty to pay down the road. Better LF in the early stages means there's more LF being overdriven in successive stages. That isn't necessarily a good thing. WRT cascade circuits I tend to prefer higher Vp even on early stages than most, but I also graduate LF pass filtration front toward back in the signal chain. This makes for ample gain while maintaining good note separation IMHE. YMMV.

Many cascade amps have moderate to low-ish Vp on the early stages. This makes for a more midrange heavy character and keeps things "predictable". Phooey!!! Note definition is lost and you end up with the same saturated "blender on frappe" tone as all the rest. Don't be afraid to use a higher Vp on early stages and moderate LF to compensate. Better note separation and overall player control is the reward.

What is WRT?

After I found the Shungang to be darker and horn sounding, I decided to raise the voltage of the first stage and see. I have to test it tomorrow at higher volume, Even at low volume, it definitely sounds brighter and less horn sounding. It is still darker than the JJ from switching the first tube back and fore. I am hoping to get rid of the horn sound, a little brighter or darker can be compensated by the treble and mid control.

Yes, I like the higher voltage better.

[Audiotexan]

What is WRT?

With regard to.

[Audiotexan]

Awesome post man! Thank you!
Learned more that I didn't know/think about!
You've raised interesting points which set the mind in motion!

Yes, raising the voltage makes a tube brighter. And improves LF. And tightens ALL frequencies produced, to a point... Remember that if you improve gain (in any area or frequency) in a cascade circuit you have a penalty to pay down the road.

So, in essence, it raises bandwidth across the board? Does it do so evenly? Or do you find that it favors one end of the spectrum over the other (assuming that's of course somewhat tube dependant...but I mean as a whole/generally speaking)?
(I generally think of transistors as linear, and tubes aren't necessarily, and that's where I get fuzzy. Educate me as needed of course!)

Better LF in the early stages means there's more LF being overdriven in successive stages. That isn't necessarily a good thing. WRT cascade circuits I tend to prefer higher Vp even on early stages than most, but I also graduate LF pass filtration front toward back in the signal chain.

When you say graduate, I think moving upward. However, with the idea that "That isn't necessarily a good thing", that seems to imply to me that you'd want to limit it getting out of control as the stages progress [front (1st stage) to back (eg: 3rd stage) of signal chain].
So I was assuming that you're attenuating it downward (meaning less LF or less HF tailored to taste so it doesn't get mushy or obnoxiously bright). Am I following? Or did I misunderstand?

This makes for ample gain while maintaining good note separation IMHE. YMMV.

From what I can gather thus far (general preference-wise), I'm probably in the same/similar camp as you sonically. So again, thanks for putting an additional idea to consider in my future testing phases!! I've always tried to test different tubes (while keeping gain parameters on the tubes/amps equal) but never thought about the bandwidth of the circuit thanks to plate voltage differences between amps! That should add another way for me to be able to sort tube preferences to amps I'd imagine. (read as: amp predisposition to tube via Vp as an additional screening/sorting parameter)

Many cascade amps have moderate to low-ish Vp on the early stages. This makes for a more midrange heavy character and keeps things "predictable". Phooey!!! Note definition is lost and you end up with the same saturated "blender on frappe" tone as all the rest. Don't be afraid to use a higher Vp on early stages and moderate LF to compensate. Better note separation and overall player control is the reward.

Do you find a stage limit? (3-stage/4-stage/etc)
Or is there a preferred 'management' method while culling frequencies back between each stage? (eg: a flat 5-10% at each stage, or just a formula relative to the gain of each stage? eg: 20% gain stage = 20% culling)

I like/agree with your idea of keeping the max from the start, and then removing as needed to maintain 'riding the edge' (I guess somewhat along the same principles that you hold in high regard with Ken Fischer.)
Regards,
AT

[Diablo]

I recently bought some Shuguang EL34-B tubes from Weber to use in a couple of amps. They don't sell matched tubes, so I bought extra and matched them up myself in the amps. They weren't greatly mismatched across the lot of 5 either. In the past, the tube pins came with extra solder blobs that needed filing to fit the sockets. The latest batch have pins that fit the sockets right out of the box. Shuguang must be responding to customer complaints, and that's a good thing. Weber is a good source for the tubes, as their prices are reasonable - $9.25 each, and they ship quickly.
https://taweber.powweb.com/store/tubeord.htm