Crack;Bottlehead OTL
Feb 18, 2021 at 9:20 PM Post #10,666 of 12,335
Funny you mention that, I'm actually building out an EL84-based amp (like the pendant) right now. We'll see how it turns out.

Just checked EL84, it's a pentode.

I think I read that triodes generally have better linearity than pentodes, have you considered triodes like 2A3 or 300B? Or what makes you choose EL84 for your future amp? Is it because there are more EL84 variants you can choose from? Just curious.:)
 
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Feb 18, 2021 at 10:06 PM Post #10,667 of 12,335
Just checked EL84, it's a pentode.

I think I read that triodes generally have better linearity than pentodes, have you considered triodes like 2A3 or 300B? Or what makes you choose EL84 for your future amp? Is it because there are more EL84 variants you can choose from? Just curious.:)

Good question! I had a really bad experience building a 45-based headphone amp last year based around the tubelab SE circuit. I just couldn't get working well enough for headphone use. It was very noisy, and no matter how I tweaked it, I couldn't get the hum to go away. It seems like everyone else is using that circuit for speakers, not headphones, so maybe that's my fault.

Anyway, people seem to really love EL84 amplifiers like the pendant, so I wanted to see for myself! I also know someone who built the same amp recently and he said it sounds wonderful. Also... a lot of the parts I had leftover from the 45 amp are compatible with the EL84 including my output transformers... So the cost of starting over is minimal.
 
Feb 19, 2021 at 2:53 AM Post #10,669 of 12,335
Good question! I had a really bad experience building a 45-based headphone amp last year based around the tubelab SE circuit. I just couldn't get working well enough for headphone use. It was very noisy, and no matter how I tweaked it, I couldn't get the hum to go away. It seems like everyone else is using that circuit for speakers, not headphones, so maybe that's my fault.

Anyway, people seem to really love EL84 amplifiers like the pendant, so I wanted to see for myself! I also know someone who built the same amp recently and he said it sounds wonderful. Also... a lot of the parts I had leftover from the 45 amp are compatible with the EL84 including my output transformers... So the cost of starting over is minimal.


Cool, I do see good reports on EL84 and its amps like the pendant. It seems to have a nice warm tune. I wish you best of luck building a wonderful sounding EL84 amp. :)
 
Feb 19, 2021 at 2:59 AM Post #10,670 of 12,335
I know nothing about the pendant amp, but I do know that EL84s can be wired to work as a triode. You give up a lot of power, but gain, I’ll call it “musicality”, which is a good trade off for a headphone amp.


That's true, triode-strapped pentodes can sound very good, I think the "musicality" comes from its enhanced linearity. :)
 
Feb 19, 2021 at 11:57 AM Post #10,671 of 12,335
I know nothing about the pendant amp, but I do know that EL84s can be wired to work as a triode. You give up a lot of power, but gain, I’ll call it “musicality”, which is a good trade off for a headphone amp.

That's true, triode-strapped pentodes can sound very good, I think the "musicality" comes from its enhanced linearity.

I'm pretty sure Ampsandsound amps are all triode strapped. It looks like a pentode/triode switch isn't that hard to implement. I'll give both modes a try. Thanks for the suggestion!
 
Feb 20, 2021 at 7:01 PM Post #10,672 of 12,335
Proud crack and SB owner here, wanna ask wheres the best place to get your hands on some munsdorf caps and which one I should be buying for the crack?

Also if any crackatwoa owners here and shed some light on whether it's a noticeable upgrade from the crack plus sb? I find very little review and impressions of the crackatwoa hence the ask . Cheers

Here is a posting that I've had my eye on. I cannot comment on the quality of the cap.

https://www.ebay.com/itm/PAIR-TWO-M...apacitor-Cap-100uf-100-uf-350VDC/312264038976

Sorry it took me so long to reply.
 
Feb 20, 2021 at 7:04 PM Post #10,673 of 12,335
Who has paired both the Bendix 6080 and Tung Sol 5998 with their Crack?

Which did you prefer and why?

I have a Bendix 6080 incoming, and also considering to get a 5998 pair eventually.

I prefer the 5998/421A coke bottle style tubes to the 6080 style. They are a bit brighter, but when paired with a quality input tube that can balance them a bit I find the combo to have more soundstage and clarity than trying to brighten a 6080 tube.
 
Feb 20, 2021 at 7:08 PM Post #10,674 of 12,335
Feb 20, 2021 at 8:27 PM Post #10,676 of 12,335
So whats some quality input tubes you recommend to pair with the 5998?

You want tubes with good, lush tone. High end would be the amperex welded 12au7 45 degree getter. Mid would be a Siemens chrome 12au7. There are several 6sn7 that work, such as a Ken rad.
 
Feb 20, 2021 at 9:26 PM Post #10,677 of 12,335
You want tubes with good, lush tone. High end would be the amperex welded 12au7 45 degree getter. Mid would be a Siemens chrome 12au7. There are several 6sn7 that work, such as a Ken rad.
Here are a few 12au7-type tubes, with a TS 5998, that have thrilled me in the BHC (and in the Woo WA3): Amperex PQ 7316, Brimar CV4003, Lansdale 12AU7.
 
Feb 20, 2021 at 11:34 PM Post #10,678 of 12,335
Here are a few 12au7-type tubes, with a TS 5998, that have thrilled me in the BHC (and in the Woo WA3): Amperex PQ 7316, Brimar CV4003, Lansdale 12AU7.

Never heard the Lansdale 12AU7, but when folks were into the Frankenstein frenzy 1 or 2 years ago I bought a genuine Lansdale 7N7 in NOS condition:dt880smile:, you know, with the yellow CBRZ Lansdale stencil shining on the glass.

I bought this tube because I initially thought it might sound like 6SN7W, because this tube shares a lot of structural commonalities with 6SN7W - they both have long glass bottle with heavy chrome top, they both have a robust extra supporting rod between the 2 plates, and the plates themselves are quite similar. But, :unamused: to my disappointment the Lansdale Frankenstein sounds nowhere like the 6SN7W, not even close. I won't say the Lansdale 7N7 Frankie a bad sounding tube, actually it's still a good sounding tube, it's just a completely different flavor. Maybe one day I shall sell it to those Lyr 3 folks, the Lansdale Frankie is still one of their favorite tubes on Lyr3 ...LOL :stuck_out_tongue_winking_eye:
 
Feb 21, 2021 at 12:25 AM Post #10,679 of 12,335
Alrighty. I have officially been defeated by the crackatwoa. I don’t think I’m going to be able to get this kit working. I’ll see what options I have from Bottlehead.

Edit: hey, I’m a 1000+ headfier now!
 
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Feb 21, 2021 at 12:48 AM Post #10,680 of 12,335
Congrats, 500 more posts to go, to become a Headphoneus Supremus :dt880smile:. Me too a 1000+ member...but I think I'll join the Headphoneus Supremus club much later as I'm quite slow in posting.

Get some good resistance and voltage measurements on your cracka2a, and ask Paul & Paul on the BHC forum, they are normally super helpful in building the BH kits.
 

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