[Frihed89]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif I would like to try the Sophia Electric 6SN7 in a Singlepower MPX3 Slam SE but it seems you all do not like them much. Currently I am using a pair of Raytheon 6SN7-GTB as the power tubes and they sound superb driven by a Tungsol 6BL7-GT.

I have never used this setup. Let me see if I have it straight.

You are using a 6BL7GT (450-500V plate) as the input tube (I think the max plate voltage on the input is around 350V) and then you are using the 6SN7GTBs (also designed for around 450-500V) as the 2 output tube and, from other posts, I think I read that you have either bypassed the high-voltage switch for the output tubes, or you never had one.

I am not being at all critical. I have never tried any of the high voltage tubes as inputs because of the lower plate voltage applied to the input.

I have read elsewhere that the high voltage tubes sound good running as outputs at low voltage, but have never heard of anyone running them as inputs.

So, what you are doing is interesting to me, given I also own an MPX3 Slam SE that's been repaired a bit.

 

[Clayton SF]

Quote:

Originally Posted by Seamaster /img/forum/go_quote.gif I got 12au7 adapters in the mail today. Thanks Glenn. They are always well made. Drop in a pair of Mullard CV4003, and let's roll......

Quote:

Originally Posted by Seamaster /img/forum/go_quote.gif Well, 12au7 was wast of money. Anyone pair WA22 with Grado beside me? I did not like my Grado RS-1 with WA22 a bit.

Oh shoot. I just ordered those adapters from Glenn to try out the Mullard ECC82/12AU7 I just ordered from the UK. I should have waited. Then again, the sound shift/difference and/or "feel" may be agreeable to my ears (mind, body & soul).

And honestly, Seamaster, thanks for all of your leg work with all of them thar toobs. It's been very enlightening. I only wish my hearing were as acute as yours.

 

[Seamaster]

Quote:

Originally Posted by Clayton SF /img/forum/go_quote.gif Oh shoot. I just ordered those adapters from Glenn to try out the Mullard ECC82/12AU7 I just ordered from the UK. I should have waited. Then again, the sound shift/difference and/or "feel" may be agreeable to my ears (mind, body & soul). And honestly, Seamaster, thanks for all of your leg work with all of them thar toobs. It's been very enlightening. I only wish my hearing were as acute as yours.

best 12AU7 is nothing special against best 6SN7 with.

I had review on this. Maybe you could email glenn ASAP to cancel order or change to something else. Or you could comfrim my 12au7 finding for me. That make you feel better? Ha ha

 

[Seamaster]

Mullard CV4003 did sound better than Sylvania 6SN7WGTA brown base. But Both Ken Rad VT-231 clear glass and Brimar bettered CV4003. 12AU7 did do bass, but tonally not very balanced (or liner) across the range. Also sound little drier than 6SN7.

 

[Clayton SF]

Quote:

Originally Posted by Seamaster /img/forum/go_quote.gif Mullard CV4003 did sound better than Sylvania 6SN7WGTA brown base. But Both Ken Rad VT-231 clear glass and Brimar bettered CV4003. 12AU7 did do bass, but tonally not very balanced (or liner) across the range. Also sound little drier than 6SN7.

I can't wait to try out those VT-99 I got from Peter in UK. I did get Glenn to make those adapters with red wire--looks ultra- ubercool, and I guess you like VT-99, yes? These were Raytheon JAN CRP 6F8G VT-99.

 

[Seamaster]

I would love to try National Union, but no luck so far. But I am really happy with Raytheon JAN CRP 6F8G VT-99 for right now.

The Mazda 6CG7/6FQ7 bettered the Amperex 6CG7/6FQ7 US made by Philips. Mazda added back lifeness and tube lushness, which at one time I thought going to lose with Amperex in exchange for dynamic and impact. They cured the bass impact problem with EML to a point I would accept and willing to live with. But still less compare with GZ34.

Then I wiped out all remianing Mazda 6CG7/6FQ7 on ebay for later use with my Melody M880. But all the tubes I got does not have shield.

One day Head-Fi member "sachu" ask me opinions on the 6CG7/6FQ7. I told him what I experienced. 5 min later he PM me said found a pair on the ebay. I check the picture he sent. Sure, a NOS pair of UK made Mazda 6CG7/6FQ7 with shield. " that is a home run" I told him. sachu worked out a deal with seller to close the auction just for him at higher price. But stilll he snatch the best tubes. I emailed him: " if you do not like the tubes when you get them, I will buy"

I am worndering shield and unshield make big difference? I am deeply in thought right now......

 

[Seamaster]

to me when matching gears and tubes, the most difficult are tonal balance and correctness. Midrange quality. Then the relation of the bass/mid bass matching other frequnency. Then treble balance.

 

[pedalhead]

Now that the adapaters have arrived, I've been comparing the Raytheon JAN 6F8G/VT99 with the Shuguang CV181. Clearly, I could have saved myself 300+ bucks. The sound opens up with these 6F8Gs, a little more space, and the bass is definitely harder hitting. Daft Punk's "Discovery" is great for testing bass tightness & impact, and this is definitely the best I have heard it. The 6F8G is less "tubey" sounding, with more of a SS flavour to it, but not so much that I no longer think I'm listening to a tube amp.

Only problem is, one of my Raytheons has some noise which is audible during quiet passages. Nevertheless, depending on how the Mazda's sound (once their adapaters arrive), I may well buy another pair of these 6F8Gs.

Anyway, everyone loves pictures, so here are a few....

Adapters from 2359glenn on ebay

6F8G details

Shuguang CV181 installed

Raytheon 6F8G + adapters installed

closeup

 

[pedalhead]

Update...after some troubleshooting, the noise isn't from a particular tube, as it doesn't follow the tube when I swap channels. I swapped the adapters from one tube to the other and now the noise is only audible beyond listening levels. No idea why, but I'm not complaining. Might be an interference thing, so I'll try shutting everything else down later. One thing I can say in favour of the Shuguangs, they are absolutely silent.

 

[tosehee]

Quote:

Originally Posted by pedalhead /img/forum/go_quote.gif Update...after some troubleshooting, the noise isn't from a particular tube, as it doesn't follow the tube when I swap channels. I swapped the adapters from one tube to the other and now the noise is only audible beyond listening levels. No idea why, but I'm not complaining. Might be an interference thing, so I'll try shutting everything else down later. One thing I can say in favour of the Shuguangs, they are absolutely silent.

Is this noise added "WITH" the adapter or audible without it?

 

[pedalhead]

It's present with the 6F8Gs installed (with adapters of course), but not present with the Shuguangs installed (no adapters obviously).

 

[tosehee]

Quote:

Originally Posted by pedalhead /img/forum/go_quote.gif It's present with the 6F8Gs installed (with adapters of course), but not present with the Shuguangs installed (no adapters obviously).

So, it's safe to say that hum is attributed to this adapter then. Not the fault w/ WA22.

 

[pedalhead]

Quote:

Originally Posted by tosehee /img/forum/go_quote.gif So, it's safe to say that hum is attributed to this adapter then. Not the fault w/ WA22.

Well it's definitely not the amp, as the Shuguangs are totally silent on full volume, but I can't say for sure whether it's the adapters or the Raytheon tubes (which could be more succeptible to noise interferance perhaps). The noise is mainly in the left channel (when I say mainly, I mean it's louder in the left channel, but also audible in the right channel if I whack up the volume). But, when I swap the tubes (including adapters) around, it stays the same...mainly in the left channel. Moving the tubes on to each other's adapters kept the noise in the same channel, but made it quieter in both channels, meaning I have to raise the volume a few steps above listening level in order to hear the noise, even out of the left channel. Don't know why, maybe just needed reseating, although for sure there still is some noise, it is no longer audible at listening level.

If it stays that way, I'm happy, but I'll do some more troubleshooting later on. I presume it's ok to power on this amp with just the adapters and no driver tubes present?

 

[Clayton SF]

Quote:

Originally Posted by pedalhead /img/forum/go_quote.gif Now that the adapaters have arrived, I've been comparing the Raytheon JAN 6F8G/VT99 with the Shuguang CV181. Clearly, I could have saved myself 300+ bucks. ... closeup

Hey pedalhead. Is that red wire on the left 6F8G adapter coming in contact with the EML 5U4G? Could that be the cause of the hum?

 

[pedalhead]

Good thought but the pics are a bit misleading as I made sure the wires were clear of the rectifier. Having said that, the left wire is closer than the right and I haven't tested that as a potential culprit, so thanks and I'll check that out in the morning (working tonight).