The "Bordello Red" GSG build and questions

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Re: The "Bordello Red" GSG build and questions

Postby Geek » Sat Apr 19, 2014 8:51 pm

Beautiful! (love)
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Re: The "Bordello Red" GSG build and questions

Postby AlexLTDLX » Sat Apr 19, 2014 9:17 pm

Ah... and now, the first issue crops up. I wasn't playing any music and turned the volume knob down. I heard a bassy, feedback-y thump out of the left speaker. Lightly tapping on the chassis also transmits out the left speaker. Maybe I've just been lucky, but I've never experienced this before. Is it normal for these tubes? Or is this tube microphonic? In my experience, a microphonic tube would ring out a tone...

EDIT: I powered down and switched output tubes (left and right); no difference. By violating the number one rule - tapping on the tubes (ok, lightly and on the bases only - that's the worst I could bring myself to do), it turns out to be the 6SL7. In the process of this murderous tapping, it suddenly stopped. Interesting it was only on the left side.

Thoughts?

BTW - sounding more and more awesome... I may not do any mods to this thing.
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Re: The "Bordello Red" GSG build and questions

Postby AlexLTDLX » Mon Apr 21, 2014 5:42 pm

I ordered a replacement 6SL7GT today. I went with a Sylvania NOS tube.

I thought you guys might want to see the underside in an 8x10 chassis. I didn't use the barrier strips - no room and additional points for weirdness to get introduced. I like to use "the whole buffalo," so the wiring is from the power transformer leads. My only concession to esoteric wiring is the input wires. After years of exhaustive research, those twisted white and gray wires are the best sounding I've ever heard. I got a little stash some decades ago from an uncle who worked at a place called Sierra Research (aerospace). It's teflon-coated silver stranded wire. I also went with 6112 OPTs because that way, we could use the whole primary winding. The specs say the 6112s have a little more bottom end than the 6115s. The sound is phenomenal. It's got that lovely SET magic, but not quite as delicate as the 2a3 I've heard. But it does have much bigger cajones than the 2a3. It's less colored than the 300b amps I've heard.

Here's the underside:
Image

And a few more finishing touches. I've found that #214 o-rings are a very nice complement to the sockets - they prevent any chance of stray paperclips or anything else from working their way into a bad place, and give everything a nice touch; and the feet are 3/8" circles punched out of an old mousepad and attached with contact cement. The jury's still out on whether I'm done, or I will do a dark wood scroll work on the front:

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Re: The "Bordello Red" GSG build and questions

Postby WA4SWJ » Tue Apr 22, 2014 6:00 am

Alex,

That is a great looking GSG. I love the colors. Nice work indeed!
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Re: The "Bordello Red" GSG build and questions

Postby Shannon Parks » Tue Apr 22, 2014 9:08 am

It's amazing how tubes open up after an hour or two. (wine)

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Re: The "Bordello Red" GSG build and questions

Postby AlexLTDLX » Tue Apr 22, 2014 10:18 pm

You know, I don't really have a lot of experience pulling 50+ year old NOS tubes out of crumbling boxes and plugging them in. The other amp has (relatively) much newer tubes. It's pretty mind blowing to think that these things have been sitting around for over half a century and you could just plug them in and they work. I guess that's why I'm not too miffed that the 6sl7gt is bad. I just ordered up another NOS one - this one is a Sylvania.

This amp just sounds fantastic. You did a great job Shannon. Kudos to you. We will "tube roll" a bit, but I'm not really pressed to mod the thing at all.

And thanks for the kind words, Ed, Gregg and zman. Hopefully there's some useful info for others in here, and it's not just all self aggrandizement :$
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Re: The "Bordello Red" GSG build and questions

Postby WA4SWJ » Wed Apr 23, 2014 5:59 am

You know, sometime back I built an amp using 832A dual tetrode tubes. They came in military style boxes that were sealed in 1945. Pulled them out, plugged them in and they worked fantastic. It is amazing how that happens. They had not seen the light of day for 65 years at the time.
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Re: The "Bordello Red" GSG build and questions

Postby AlexLTDLX » Wed Apr 23, 2014 8:55 pm

It is amazing. My Sylvania 6sl7 showed up today. What a difference. First of all, there much more gain now. Secondly, it's even quieter than before. Thirdly, it's got more "sweetness" and "bounce" - if that makes any sense. A lot more. The old tube must've been weak (I'm thinking it wasn't NOS, but used).
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Re: The "Bordello Red" GSG build and questions

Postby Shannon Parks » Thu Apr 24, 2014 8:19 am

AlexLTDLX wrote:It is amazing. My Sylvania 6sl7 showed up today. What a difference. First of all, there much more gain now. Secondly, it's even quieter than before. Thirdly, it's got more "sweetness" and "bounce" - if that makes any sense. A lot more. The old tube must've been weak (I'm thinking it wasn't NOS, but used).


All the Sylvania small signal tubes I've tested seem to have a little more transconductance than typical (RCA) datasheet specs. Probably was started in the marketing department to differentiate from GE and RCA. Since everyone had a tube tester it was evident. Kind of a Chrysler-Chevy-Ford thing between the tube companies, I bet.

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Re: The "Bordello Red" GSG build and questions

Postby AlexLTDLX » Sat Apr 26, 2014 9:53 pm

Ok. I know I said I wasn't gonna mess with it. I swore I wasn't going to mess with it. It sounded a good deal better than the Dynaco. Once I replaced the bum tube with the black plate Sylvania, everything was fantastic. It was smooth and there was nothing wrong with the sound. The midrange was phenomenal, the bass awesome and the highs crystal clear and highly defined. Heck, it could even handle Mahler's Symphony #8 without turning into a mushy mess (the Dynaco has a little trouble with that one - which says something considering it's got over 10 times the power of the GSG).

But one thing bothered me. To me, SET amps are supposed to have a detail and "sweetness" that requires one to pick up one's jaw off the floor. The kind of thing where you forget you're listening to recorded music and a catch a glimpse of one of the speakers in reminded shock. That wasn't totally there. And the soundstage was great, but I thought it could do better.

So I decided to pull out the Mundorfs and put in the caps from the Bill of Materials. They look like orange drops, but I'm too lazy to look up what they are for certain right now. I had the caps swapped in about two minutes - I didn't even pull the tubes. I just laid the thing back on a folded up towel and had my way with it.

Here's the results (thus far):

Out of all the reviews I've read, this one describes Mundorf Supremes perfectly:
http://www.laventure.net/tourist/caps.htm

They gave them an "A" rating - below "AA" and "AAA." But still better than most (the list goes down to "F"). They describe them thusly:

"It is rich, detailed, and full-bodied, though a bit softer sounding than the Duelund VSF. Relatively free of glare."
"Properly placed, they can mitigate the hardness of a digital front end."

But do not confuse that "softness" with lack of treble. Tito Puente's "Take Five" will sizzle your ears off with these. The best way to "technically" describe them is as if someone pulled back the upper mids a little bit. Vocals lose their "edge," and just become buttery smooth. They sound great, just with no edge. And this probably leads to the sense of a compressed soundstage.

Now I also used to play in bands in my younger days, so even though I've taken great care to preserve my hearing in the last decade or so, some damage has been done. I find I like that "edge." And I associate that edge with the SETs I've heard.

The Bordello Red travels from playing through the big 3 ways on one side of the house to my bedroom in the evenings, where it plays through some aesthetically gorgeous, but completely mediocre mini Teac speakers (with lightly modded crossovers - I can't leave anything alone).

First impressions of the B.O.M. "Orange Drops:"

It's a little a hard to give a completely honest assessment on the mini Teacs. At first they sounded kind of flat and crappy. I was used to the smoothness of the Mundorfs. After a little time, things started to fall into place. First, they "opened up" - that edge that I've been referring to made it's appearance, then the highs. Last to fall in was the bottom end. Somewhere about halfway through this process I found myself looking at the speaker.

Tomorrow I'll bring the Bordello to the big speakers and see what happens. I guess I'm not done quite yet...
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Re: The "Bordello Red" GSG build and questions

Postby Geek » Sat Apr 26, 2014 10:44 pm

Opinions are nice, but remember all that matters is the sound to YOUR ears ;)
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Re: The "Bordello Red" GSG build and questions

Postby AlexLTDLX » Sun Apr 27, 2014 3:16 pm

I agree; sort of. I do intend to use this thing for work on occasion - it will be sitting here at the desk in the editing suite after all. I'll probably run the odd project through it just to give another "opinion." I'm rather used to different audio devices/speakers from a professional perspective - everything from those spaceship Tannoys to Genelecs to Auratones (awfultones) to Fostex 6301b's (actually becoming my favorites as I age - I used to love Genelecs, now they sound like someone beating a (very expensive) trashcan lid.) But all of my personally-owned professional audio monitoring gear is at least modified by yours truly. For what it's worth, I don't work in music - I work in TV and Film. Tomorrow I'll be in a studio with Tannoys (the non-spaceship variety), for example.

I'm listening to the Red playing through the big speakers with the Orange Drops (they actually are, I looked at them today - 715p's).

I'm definitely forming an impression; I'll share it a little later on.
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Re: The "Bordello Red" GSG build and questions

Postby AlexLTDLX » Mon Apr 28, 2014 8:51 pm

An interesting thing happened on the way to the forum today...

I was playing music through the Bordello today while uploading some huge files, and my 9 year was reading her kindle on the carpet. Out of the blue, she looked up at me and said, "Daddy, the music sounds better."

She was right. A lot better. The Orange Drops are still in it, and the music went from bright and "glaring" to "Oh my god that's amazing" over a relatively short span of time. And then I heard things I've never heard before on recordings I've critically listened to for years - like fingers on the keys of the Hammond in "Lazy Bones" or a bit of scat during the fade out of "Didn't He Ramble." These were not barely perceptible, either. They were quite clear. I've just never heard them before. I've had this album since about 1997.

So here's a question - did the caps "burn in?" Why is "burn in" ALWAYS reported as an improvement? Why does the sound never get worse? Is it a real thing, or psychological? (let's not get in to "perception is reality...") And finally, anybody else "cap roll" in their GSG?
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Re: The "Bordello Red" GSG build and questions

Postby Geek » Tue Apr 29, 2014 12:08 am

Possibly.

Caps do "burn in" and so do tubes.
(actually, a plethora of items do. Technically even verifiable on test equipment)

The fact an untrained ear caught it is a testament to your combination [:)
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Re: The "Bordello Red" GSG build and questions

Postby 20to20 » Tue Apr 29, 2014 9:52 am

AlexLTDLX wrote:
So here's a question - did the caps "burn in?" Why is "burn in" ALWAYS reported as an improvement? Why does the sound never get worse? Is it a real thing, or psychological? (let's not get in to "perception is reality...")


Ya, I don't subscribe to the theory that perception is reality, either. So why IS burn-in always described as an improvement? A question for the oracles.. Or for discussion 'round the bar table that would go nowhere.

This is a fun hobby for sure. It gives a technically minded person something to be creative with. It's full of drama and extremes at times, which is usually a humbling experience. Like a tightrope walk on a windy day.

We might be able to find some clues leading to something of an answer actually in your posts. Working inTV and film you should have some meaningful insight into drama and superlatives that will be helpful.

After you changed the tube you described the amp with the Mundorfs as,
everything was fantastic. It was smooth and there was nothing wrong with the sound. The midrange was phenomenal, the bass awesome and the highs crystal clear and highly defined. Heck, it could even handle Mahler's Symphony #8 without turning into a mushy mess


Smooth, phenominal, awsome, crystal clear and highly defined sounds like a 10/10 to me.

But you didn't yet hear what you were looking for,
a detail and "sweetness" that requires one to pick up one's jaw off the floor.


So you swapped in the OD's and heard,

... they sounded kind of flat and crappy. I was used to the smoothness of the Mundorfs.

After a little time, things started to fall into place. First, they "opened up" - that edge that I've been referring to made it's appearance, then the highs. Last to fall in was the bottom end. Somewhere about halfway through this process I found myself looking at the speaker.


Then in the next description of the sound as the burn-in progressed you said,
The Orange Drops are still in it, and the music went from bright and "glaring"
to "Oh my god that's amazing" over a relatively short span of time.


So it went from flat and crappy, to, you were looking at the speaker in wonderment as the they opened up, to, bright and glaring, and then to, "Oh my god that's amazing."

Your first descriptions basically attributed the quality of the sound from the amp entirely to the Mundorf coupling caps. This kind of focus on one component as the make it or break it magic part happens all the time.

Great paint job!

Bartender!... More drama and superlatives for these gents. And I'll have a XX, grande, por favor.

20
Last edited by 20to20 on Tue Apr 29, 2014 11:32 am, edited 1 time in total.
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