[headphonejunkie]

I would like to hear how those bugle boys sound.

 

[Sathimas]

My new tubes arrived yesterday but I don't have a multimeter myself and have to borrow it.
Since I couldn't get one yesterday and today also, they'll have to wait until next week because
I'm going to Egypt for one week

Holidays - I'm coming (with loads of books for university in my luggage

)

 

[headphonejunkie]

I just received my amperex golden globe 12au7's made in great britain yesterday. They sound pretty darn good. They have a lot of air and quite a bit of bass. The bass is nice and clear too. There seems to be more emphasis on midrange but I have to do more listening to be real sure. I like them. I am going to have to pick up a bugle boy now just to hear how nice that sounds. This soha is quite a nice amp. I think I can be happy with this little amp for quite a while. It matches my grado 225's quite well.I was going to build myself a cavelli jones. I am half way there. This amp is so nice I think that that project is going on the back burner for now.

 

[headphonejunkie]

Quote:

Originally Posted by M_Bipartitus /img/forum/go_quote.gif I have ~3 GE 5963 5 stars that are ok. I prefer the RCA cleartop 12AU7A (NOS '64). Now that the amp has gone a week with no problems (and the gf is out of town) I'll be testing the NOS Amprex Buggle Boys, CBS, and Telefunkens at home. Also I've found the noise floor on my computer is a bit high for careful testing, so time to wire up the DVD-A player.

I suppose it does depend on which headphone you are using too. I see you have an rs2. That is probably a very warm phone (never heard one) so the cleartop does not sound too harsh for it. My cleartop with my 225's seems a bit on the harsh side. The cleartop also seems to lack the air my RFT and amperex gold globes have.

 

[headphonejunkie]

I just wanted to say that my amperex gold globes are some nice tubes. they sound similar to the RFT but have more emphasis on mids. I like them. They are my number one tube at the moment. I wanted to try something made by mullard and these do sound nice. Not bad for $24 shipped for two from ebay(unfortunately used).

 

[Sathimas]

I finally managed to listen to my new tubes today

I had one 5963, one 5963 5 Stars and one 6680, all GE.

The 6680 is my absolute Favourite!
Switching beetween 5963 and 6680 is like switching loudness ON (5963) /OFF (6680).

The 6680 is more detailed across the whole frequency range, cymbals AND base guitars are much better.
The strange thing is that there is actually a little less bass but the resolution is better.
Also cymbals are more accurate but not as loud/disturbing as with the 5963.

Sounds very neutral to my ears, while the 5963 is far more "in your face".
I prefer the 5Star over the standard 5963, sounds very similar but the 5 Star has more pleasant heights.

The 5963 was somehow disappointing anyway, I cannot make out any real big difference to the standard RCA 12AU7 Jeff sold me.
A little more detailed, but almost the same sonic characteristics to my ears.

So thank you very much for recommending me the 6680, its perfect for me.
I'll keep the 5 Star GE 5963 as reserve and "loudness button"

Luckily, I can exchange the 5963 and the 6680 without adjusting the voltages, they change only about 0.5Volts when I exchange the tubes.

 

[tomb]

Quote:

Originally Posted by Sathimas /img/forum/go_quote.gif I finally managed to listen to my new tubes today I had one 5963, one 5963 5 Stars and one 6680, all GE. The 6680 is my absolute Favourite! Switching beetween 5963 and 6680 is like switching loudness ON (5963) /OFF (6680). The 6680 is more detailed across the whole frequency range, cymbals AND base guitars are much better. The strange thing is that there is actually a little less bass but the resolution is better. Also cymbals are more accurate but not as loud/disturbing as with the 5963. Sounds very neutral to my ears, while the 5963 is far more "in your face". I prefer the 5Star over the standard 5963, sounds very similar but the 5 Star has more pleasant heights. The 5963 was somehow disappointing anyway, I cannot make out any real big difference to the standard RCA 12AU7 Jeff sold me. A little more detailed, but almost the same sonic characteristics to my ears. So thank you very much for recommending me the 6680, its perfect for me. I'll keep the 5 Star GE 5963 as reserve and "loudness button" Luckily, I can exchange the 5963 and the 6680 without adjusting the voltages, they change only about 0.5Volts when I exchange the tubes.

You have a very optimum selection, which may be why the $4 GE 5963 is not more impressive. However, as for the GE 6680, my sentiments exactly. Glad you like it - it's one of those nice little discoveries one can make in rolling tubes.

You might also try some of the NEW tubes - the JJ 12AU7 and the Electro Harmonix 12AU7 are particularly nice, but beware the EH - it has an unbelievably long break-in. Neither have the sweetness in the highs of the GE 6680, though - it's like connecting a high dollar boutique film cap in the circuit.

 

[Sathimas]

No tomb, you will not tempt me to try any more tubes ... NO!!!!

I spent far enough money for now, next step will be another amp, if there will be another step.

Or maybe Diamond Buffers for the SOHA.
But until today nobody told my what kind of improvement they'll bring.

 

[headphonejunkie]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif You have a very optimum selection, which may be why the $4 GE 5963 is not more impressive. However, as for the GE 6680, my sentiments exactly. Glad you like it - it's one of those nice little discoveries one can make in rolling tubes. You might also try some of the NEW tubes - the JJ 12AU7 and the Electro Harmonix 12AU7 are particularly nice, but beware the EH - it has an unbelievably long break-in. Neither have the sweetness in the highs of the GE 6680, though - it's like connecting a high dollar boutique film cap in the circuit.

I like the EH but don't care for the JJ. Of course, these differences in many cases are not great but the JJ just sounds cheap.I would have to listen to it again to see exactly what it was I didn't like about it.

 

[tomb]

Quote:

Originally Posted by Sathimas /img/forum/go_quote.gif No tomb, you will not tempt me to try any more tubes ... NO!!!! I spent far enough money for now, next step will be another amp, if there will be another step. Or maybe Diamond Buffers for the SOHA. But until today nobody told my what kind of improvement they'll bring.

Well, maybe you're right - the GE 6680 is the greatest find, IMHO, and now you have it.

Quote:

Originally Posted by headphonejunkie I like the EH but don't care for the JJ. Of course, these differences in many cases are not great but the JJ just sounds cheap.I would have to listen to it again to see exactly what it was I didn't like about it.

Yeah, you're definitely right - the EH is actually much better, but the JJ is pretty reliable right from the start and it has a pretty good response. Both are very easy to find, being new production, which is the main reason I mentioned them. The EH is probably my favorite new tube. Sathimas compares the GE 5963 to a Loudness switch, but the EH 12AU7 is way and above the most powerful 12AU7 I've tried.

 

[headphonejunkie]

Quote:

Originally Posted by Sathimas /img/forum/go_quote.gif No tomb, you will not tempt me to try any more tubes ... NO!!!! I spent far enough money for now, next step will be another amp, if there will be another step. Or maybe Diamond Buffers for the SOHA. But until today nobody told my what kind of improvement they'll bring.

I think I have 8 tubes now. It is addicting.

 

[Sathimas]

I have 4 atm - and I'll keep only two of'em.

For the next months I'll spend more money on "software" again.
Some of my favourite bands are about to relaese new albums.

But maybe someone here could tell me about the diamond buffers?

 

[headphonejunkie]

Go to headwize.com and look up diamond buffers in the DIY section.There also are going to be JISBOS buffers too. I am thinking of building the JISBOS buffers.

 

[tomb]

discrete buffer: jisbos (air wired)
This is the link, as Headphonejunkie says. However, if I'm not mistaken, these will be the only buffers. Steinchen actually did four different kinds at one point:
1. MOSFET buffer
2. Diamond buffer
3. Jisbos buffer plug-in (double decker boards)
4. Jisbos air-wired (above).

If I remember correctly, the MOSFET buffer was never stable and was abandoned. The Diamond Buffer (DB) had a DC servo to control offset, but every time the offset was dialed out, there was very little left over to bias the buffer. The Jisbos buffer plug-in was designed to plug directly into the opamp position on the SOHA board. It required two boards stacked on top of each other to do this. However, I think Steinchen finally decided that these were way too difficult both from an SMD standpoint and because of poor structural stability.

The Jisbos air-wired are completely through-hole and have been successfully built by other people. The Jisbos is an original buffer design from Amb, but Steinchen has made the implementation specific for the SOHA. He also remarked that they were the best-sounding, anyway.

 

[tomb]

MORE: I guess we should add that the real weakness in the SOHA design is the opamp output stage. Most, if not all, opamps were not designed to drive a load directly - at least not one like some of the headphones we use. This is similar to the development that the original Millett Hybrid went through. Originally, the Millett was provided with a monolithic buffer output stage - the BUF634's. Later, Amb made a small conversion that allowed the OPA551 to work in the same way as the BUF634's, thereby increasing the relative current available. The same could be achieved by stacking the BUF634's, but that was more expensive.

Later however, Steinchen (no coincidence that he's doing it for the SOHA) developed the famous Millett Hybrid Diamond Buffer boards, which gave the Millett unparalleled sound quality capability. His work formed much of the basis of the Millett MAX design, and his website remains today as an invaluable reference for biasing a DB and for his excellent reviews of the different output transistors that may be used. His website is directly referenced for the DB's from the MAX website:
http://www.diamondstar.de/dDB_overview.html

As mentioned above, Amb actually designed the Jisbos circuit. However, as with the Millett, Steinchen recognized that the greatest improvement that could be made to the SOHA would be to add a discrete buffer. If his previous work is any indication, the Jisbos buffers will put the SOHA into a new level of sound quality and will be in much demand.