The DIY'rs Cookbook

[johnjen]

Yeah these Westinghouse 6L6GC's are different in shape and size from any other I have seen as well.
At first I thought they weren't the right tubes, until I saw their markings.

But, ya know, them pesky Germans, tend to do things just a bit different than most others and these 6L6's are a prime example.

JJ

 

[johnjen]

So we've been chasing the mysterious and tenuous gremlins that lurked, unseen inside the Purp-Amp.
And as of tonight they seem tamed and put to bed, perhaps permanently so.

The magic seemed to be related to matching operating points of various kinds and nailing certain amounts of voltage and current in key places.
Like tuning an engine, when all parameters are dialed in, it just purrs right along.

Both channels measure 0.000mvac s/n which equates to -120dB
The rattle and very low freq noise has receded, remarkably so.

The SQ has taken a decided and major step up and needs more settling in time, as per usual.
The DHT Gudness has stepped up it's game and there is definitely much more there, there…

And there are a few more tweaks that are slated to be made, especially if these latest changes yield even greater results than we expected.

It certainly is a welcome 'mutha may I' step up or 2 or 16384740637630.4876

JJ

 

[johnjen]

So I've put my tube projects on a brief pause of late.
Poking fingers inside live tube circuits is not for the average DIY'r and ones full attention needs to be focused on all those pesky details.
Like that pointy piece of metal, right there ––> which has 300+volts of hand tingling excitement should it be nudged even slightly,.
This certainly suggests caution should be observed when there are 'distractions' aplenty, just waiting to 'surprise' you.

And project developments have continued in the background with some rather unique and nifty designs nearly ready to build as prototypes.

And I can feel that itch to start poking around inside the amps innerds, begin to grow.
Kinda like 'damn the torpedo's, power that puppy up and poke away'…

JJ

 

[johnjen]

Now I did it…!

I fussed with the circuitry of the Purp-Amp and then added a full dose of secret sauce to the entire amp, all in one Swelled Foop.

And um, it still needs moar time to settle in/out/down/up er sumpt'n.

But this iteration has my head danc'n on my shoulders and me singing along, with full engagement with the lyrics.
And nuances galore are being served up with penaché as it continues to focus in and reveal that there is more there, there.

Just like I like…

JJ

 

[johnjen]

The secret sauce has been simmering quite nicely for 2 days now and the extreme bottom end (sub 20Hz and up) is comming back, a very good sign.
It's to the point I can feel the drum heads continue to vibrate well after they have been struck.

And the mids have yet to blossom into their peak.
But that usually follows after the extreme bottom end comes into focus and everything tightens up.

JJ

 

[johnjen]

Progress report on the Purp-Amp.

The mids are not spectacular, nor is the bottom end nor top end.
This, to some, might seem like things have gone sideways and the overall SQ has taken a step backwards.
Sorta M'eh like.

Au Contraire…

In this case, not spectacular, means that nothing is sticking out, shouting "Hey, Look At ME!!!!
And that the SQ is deceptively simple and is seemingly nuth'n to write home about…

Except that the soundstage is VERY reflective of the venue in which it was recorded, regardless of type of venue.
There is a sense of precision to each 'voice', in 4d space, while being able to hear into the harmonic structure and the playing technique(s) being recorded and played back.
And the more I listen the deeper the degree of depth of inner (and outer) detail becomes.

It IS deceptive in that at first listen nuth'n seems note worthy , but then I notice that a particular 'voice' was different than I remember, and it has more there, there.
Then other 'voices' follow suit so that the overall character of each track reflects, that there IS more there, there.

After a while, yet again, I'm back into realizing I'm hearing my music as if anew, again.
Sorta like the niftyness of this SQ sneaks up on me and then smacks me upside my head.

And what with me being a fan of the very bottom end, the improvement and coupling from the sub-sonic to all of the rest of audio bandwidth, is surprising me, as it becomes 'more attached' to every 'voice', regardless of its nature, which is raising the bar, and in most gratifying ways.

Yeah the Purp-Amp is blossoming quite nicely I'd say, and doing so with SDSG (SuperDuperSuperGlue) only needing to be used sparingly.

JJ

 

[johnjen]

The latest changes I made to the Purp-Amp was to start using CBS (Hytron) 6BQ7A tubes.

This has resulted is a significant step up in SQ, especially I5 (Intelligibility), where lots of those subtle nuanced inner details reside.
In short, again, there is refinement to the entire soundstage and to every 'voice' therein.

And I also have a set of Brimar tubes from England inbound, so a shootout is slated in the near future.
And since the 6BQ7 tube was originally designed for use in a TV as a VHF amplifier, it never 'caught on' as an audio tube, which is great as the price for these tubes remains 'reasonable', in distinction to crazy stupid expensive.

JJ

 

[gefski]

The latest changes I made to the Purp-Amp was to start using CBS (Hytron) 6BQ7A tubes.

This has resulted is a significant step up in SQ, especially I5 (Intelligibility), where lots of those subtle nuanced inner details reside.
In short, again, there is refinement to the entire soundstage and to every 'voice' therein.

And I also have a set of Brimar tubes from England inbound, so a shootout is slated in the near future.
And since the 6BQ7 tube was originally designed for use in a TV as a VHF amplifier, it never 'caught on' as an audio tube, which is great as the price for these tubes remains 'reasonable', in distinction to crazy stupid expensive.

JJ

Are you buying from Langrex UK? They have a bazillion tubes and other components, decent pricing.

 

[johnjen]

Nah, ebay.
But I'll look them up and add them to my ever growing collection of sources of tubes etc.

Just because "to much is never enough"… hahahahahah

Thanks for the suggestion!

JJ

 

[gefski]

Nah, ebay.
But I'll look them up and add them to my ever growing collection of sources of tubes etc.

Just because "to much is never enough"… hahahahahah

Thanks for the suggestion!

JJ

They have a “store” on eBay in addition to their direct sales.

 

[johnjen]

Ah yes.
I'll keep an eye out for them.

Thanks JJ

 

[johnjen]

Ok so the Brimar 6BQ7's showed up.
I cleaned the pins on one of them and replaced the Hytron (CBS) tube and turned on the Purp-Amp and let it settle in for ≈ 15 minutes before donning my J-mods.

Um, er, well, it's like this see, um, I wasn't prepared for what happened, not only next but for the rest of the evening of listening…

Wholey BatSchiit them'r some impressive tuubz…

There is MOAR there, there, everywhere.
and that was only after about 5 minutes,
and then it started to open, expand, focus up and down, top to bottom, which continued for the next 10+ hrs.

In short not only has the amp 'hit a lick', this tube combination has kicked the bar so far up that I can't wait to hear ALL of what it's going to 'bring to the paaarteé' in 1-200hrs.
Every single sonic/acoustical attribute that I have ever described and use to determine 'Better', and more, has risen to new heights, as in this is the best SQ not only this amp has ever delivered, but is also 'better' than I have ever heard, with but one exception, and that was 46 years ago.

The bass has additional refinement, inner detail and 'texture', the mids are standout/in/up glorious, the top end has a degree of refinement and inner detail that is sublime.
But it's the totality that is truly stunning.

The entire soundstage has deepened as it has moved in closer and further back, at the same time, and is much more stable thru time (not just a stable 3d image, but the sonic images, as they progress thru time (4d), is more stable and 'real' as well).

This is one BIG step closer to the goal of achieving a CNST (Central Nervous System Tap) where I'm not just listening to the music, rather I'm immersed within the music as it seemingly surrounds me and I find myself in the middle of the sound field.
IOW it's not just 'out there', it's also 'in here' where I am.

And if this 'settling in' continues in the same way that previous 'upgrades' have done, with this immediately apparent increase in SQ, then I would suspect there is significantly more to come.

I'm not sure what that means, or what and how it will manifest, but I aim to find out.

JJ

 

[johnjen]

And thanks to the tuube wizardry of @bcowen I have found 2 more sets of 6BQ7A tuubz to compare to these 'stock' Brimar's.
One set made by Brimar is Cossors which are 'hand picked' (aka Tweako) examples of the Brimars.
And the 2nd set are Mullard's made in 1960 in Great Britain and have the BVA (British Valve Association) logo on them as do the Cossors.

Thus far these 'stock' Brimar's are outstanding examples of these tuubz and the SQ results are stellar by any and all measure.
I keep hearing not only nuances but entire instruments that were 'buried' in the music.
They can now be heard, focused upon and followed as the song plays, where as before there were hints now and then that they even there.

Case in point is The Who's track Eminence Front on their It's Hard album.
The bass player has a really nice sound that contributes a nice contrast as the track unfolds.

JJ

 

[bcowen]

So I've put my tube projects on a brief pause of late.
Poking fingers inside live tube circuits is not for the average DIY'r and ones full attention needs to be focused on all those pesky details.
Like that pointy piece of metal, right there ––> which has 300+volts of hand tingling excitement should it be nudged even slightly,.
This certainly suggests caution should be observed when there are 'distractions' aplenty, just waiting to 'surprise' you.
JJ

LOL! I learned early-on in my DIY audio life that the best way to discharge a 1500 uF, 450v cap is NOT using your body as the resistor to ground....

 

[johnjen]

This is akin the 'Mr Science Show' where he has 'Jimmy' (not his real name) hold 'those' 2 wires, followed closely there after by a staccato vibratory yelp for help.

I just thought I'd throw in a complimentary example of methods to discharge a power supply cap, with similar 'learn by doing' results…
hahahahahahahahahahahaa

JJ