Will the monoblocks be replaced?

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Offline Alonzo

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Reply #15 on: November 02, 2023, 02:19:10 PM
Doc,
Have you considered just being the "design" portion of BH?  You design and build a prototype and sell us the design and BOM?  Cuts out the inventory, storage and shipping but still advances the changes and improvements you see to your product line.  Since you do such a good job on the manuals, if you provide it with the prereq pictures, you can charge an appropriate amount to support your product.

Alonzo
Gameroom:>Mainline to HD820, SR45 to Pipette
>BeePree Kaiju & SII to Altec 19 knockoffs
Office:>BH Stat amp to Koss 95x, T20 SET to JBL 4309s
Den:> MorePlay 845 SET to Altec Valencia's


Offline Doc B.

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Reply #16 on: November 02, 2023, 03:16:15 PM
I appreciate the idea, Alonzo. We're focusing on winding back our work lives these days with an eye on retirement. Probably the best outcome for everyone would be if someone wanted to step in and buy Bottlehead. It's pretty much a turn-key operation with a large and loyal customer base, well developed supplier relationships and a steady profit margin. The only downside is that I am getting old! With some fresh, enthused management Bottlehead could put out a lot of product ideas that we have developed but lack the energy to deliver at the pace we used to.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Online Thermioniclife

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Reply #17 on: November 03, 2023, 07:00:29 AM
Perhaps PB. could fit the bill.

Lee R.


Offline Paul Birkeland

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Reply #18 on: November 03, 2023, 07:39:34 AM
Perhaps PB. could fit the bill.
This is something I have certainly considered, and I have also discussed some possible partnerships to avoid having to take on substantial debt.  We shall see what shakes out...

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Online Thermioniclife

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Reply #19 on: November 03, 2023, 12:21:35 PM
Well I wish all at Bottlehead the best in the future. It would be a shame to see Bottlehead go to some entity that has not been involved in the past and lose the continuity of your ethos. PB has the skill and PJ has invaluable knowledge that took decades to acquire. Just one old man's opinion.
Regards, Lee

Lee R.


Offline 2wo

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Reply #20 on: November 03, 2023, 05:09:21 PM
Maybe you can trade for motorbikes... John

John S.


Offline Vitola B1

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Reply #21 on: March 27, 2024, 01:51:58 PM
Prototype parts are on the way for two separate prototyping projects, one if which will definitely be monoblocks.

Hello Paul, I hope you are well, there is something new with the monoblocks prototypes, how did it seem to you listening to them?



Offline Paul Birkeland

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Reply #22 on: March 27, 2024, 05:51:08 PM
Yes, I had to double check with the boss before really saying a lot. 

Back around 2017, I had a local repair client in Woodinville, WA who had brought me a lot of hopeless projects he had amassed over the years, and one day he showed up with a box of parts and paperwork rather than some broken piece of vintage tube gear.  Apparently he had paid someone else locally a long time ago to develop an amplifier design around the 811A tube, but nothing had really worked out for him and he wanted me to look over what he had.  The design was quite odd and had the 811A cap coupled to the previous stage and zero biased, the output transformer was only 5K, and there wasn't any feedback around the amp.  Having pointed out these initial obvious defects, he asked me to continue the project, and that set me off on a lengthy tangent of designing and building a lot of class A2 amplifiers and learning as much as I could from the few competent designs posted here and there. 

Eventually I did manage to resolve the challenges of working with the 811.  Primarily the massively Rp of the 811A (around 30K) needed a lot of feedback to work into any kind of reasonable output transformer, but global feedback around a single ended amplifier ends up creating an oscillator.  Ultimately the solution was to apply the same methodology that Paul Joppa used in our Seductor EL84 amplifier to deal with this issue, as this avoids global feedback and creates a far more stable amplifier that works into a relatively standard output transformer.  Still, nailing down this circuit was a lot more of a guess and check process compared to a rigorous design, so it took two years of fiddling to finally get the circuit into its final form.   

Having delivered 18W 811A SET amps to my local customer, he immediately asked me for something bigger, and I stretched things out with about 60% more B+ and a lot more plate current, and I managed to (just barely) make a pair of 50W 810 SET amps.  With a nice payout from that job, I began to wonder what I could make that would pass muster with Doc B.  I knew he wouldn't go for the plate caps on an 811A, and also the voltages needed to be kept more in the realm of a 300B amp.  Going for power well beyond what a 300B could deliver meant 25+ watts and the list of tubes I could find to accomplish this seemed pretty small, but there was the new production 805A triode that seemed to fit the requirements. 

With a slightly better grasp of circuit optimization and help from PJ, this amp (first picture below) came together in just a couple of months in 2019.  With some custom made Sowter parallel feed iron, these monoblocks were awesome!  I really regret selling them, and their current owner is very happy with them!  This was an amplifier that I wanted to make more of, and it used our Kaiju power transformer and just a large 3K parallel feed output transformer and a manageable 30H plate choke.  Power output was right on at 30W with new production tubes, and slightly more with old stock specimens. 

In the five years that followed form this project, I've built a whole bunch more class A2 single ended amps with this same topology, and PJ has offered a lot of support in nailing down better design techniques.  PJ also served up a massive quadruple parallel 6550 circuit that belted out 50W and is one of the heavier tube amps I've ever had to move! We have ultimately settled on this 30W target on our standard 300B power transformer, and PJ designed up some proprietary iron for this project that is working quite nicely.   

The results of this iteration are shown in the second photo (odd colors chosen help ensure they stay in my listening room).  Power output from new production 805A tubes is 15W at 1% THD, 28W at 5% THD, and 30W at 10% THD.  Power available at 35Hz is only a watt or two lower than these numbers.  Frequency response is -1dB at 16.5Hz and 22.3kHz, and the damping factor is a bit higher than our typical amps at 4.4. 

Sound wise, these amps sound large and fast with ample reserve power and a good ability to remain composed through difficult passages.  The higher damping factor is very rare from a high power SET amp, and this leads to tighter bass and better synergy with a wider variety of speakers. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Paul Joppa

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Reply #23 on: March 27, 2024, 07:03:58 PM
When we listened to these amps recently  (driving the Jaeger speakers), I thought they sounded clean, relaxed, and authoritative at the same time, without losing the warmth of SETs. PB really came up with something special.

Paul Joppa


Offline sl-15

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Reply #24 on: March 27, 2024, 07:19:30 PM
I love the color scheme of the second photo amp. What kind of finish is it? A paint or is it the material itself that has that awesome sparkle green? Well done. So are you eventually offering it as a kit?

Stefan Hampel
Soundsmith Carmen, modded Technics SL-1200mkII, Thorens TD 125 mk2 with SME V, Eros, Extended Foreplay III, BeePre2, Crack, Pioneer Spec 4, Sonus Faber Electa


Online Thermioniclife

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Reply #25 on: March 28, 2024, 04:48:04 AM
Yikes!  ;D

Lee R.


Offline Doc B.

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Reply #26 on: March 28, 2024, 05:51:13 AM
A little background on this- you longer time customers know that we used to do a lot of audio shows with high end speaker manufacturers, demoing Tape Project tapes with our electronics in their rooms. I would often be asked if we had an amp that would be suitable power-wise for their speakers. And I would love to have our stuff used in studios where it could be an effective tool for the engineer who needs to be able to crank up the levels for some work. Unfortunately for the show environment and also for the studio environment - where the type of speakers these high end manufacturers were making were used - there had to be a lot of headroom. And so with those speakers an 8 watt 300B amp would not cut it when the levels went really high. More than once it was suggested that around 30 to 50 watts would be adequate.

 Making a tube amp in that power range is easy. Making one that sounds the way I wanted it to sound is very difficult. And so we had a string of designs over the years that just didn't quite cut it sonically, or ended up so expensive to make that we would never be able to sell them. We've been keeping this project on the QT for a long time. The big 6550 amp was really nice but too huge and expensive. I was not in love with the original 811A build, but the project that PB built in 2019 got my attention and I thought it was worth pursuing. There are a lot more tedious details that lengthened the timeline like Covid slowing things down and it taking for f***ing ever to get output iron samples. 

FF to a few weeks ago. Peebs said he had some prototypes that were pretty much like a finished product would be and he would bring them over for a listen. He was bringing PJ along. I asked Matt to come by so he could meet the guys and we could share his Pipette/Subette small speaker setup along with listening to the big amps on my personal Jagers, which were going home with PJ. The small speakers were quite impressive, particularly with the new subwoofer. That's for another thread.

The next setup was BeePre2/new amps/Jagers driven by a mac mini playing tidal files via a USB to AES converter thru a Nagra 7 as DAC. As much as I was disappointed with my interactions with Nagra staff several years ago, I do think their stuff sounds phenomenally good and the Nagra 7 is quite a great sounding piece of gear.

OK, preamble aside. The sound of Jagers with these new amps was IT. IT being the sound I have been looking for for maybe 30 years. IT has the deep listening resolution, sonic hologram localization kind of thing going on that SETs do in spades. And IT has super tight punchy bass that SET seldom has - even better than our other amps. Top end is lovely, extended and sweet. Vocals are very real sounding. Piano has the dynamics to sound real. Everyone in the room was pretty spellbound.

And then I realized that the Jagers were going away! Just when we had an amp that made them sound the best they ever sounded, something I think could stand up in a mastering room. I do have another pair at home for my own use, but we have had to stop production due to issues with supply and our past cabinet maker seemingly losing interest. So where we are at the moment is moving ahead with the big amps (I'm thinking Category5 for the name, in the Pacific Rim tradition of Jager and Kaiju), and Matt and I are in the midst of working up a new, slightly updated version of the Jagers.

When this all comes together it will likely be expensive. But in terms of the sonic result it might be the best deal we've offered. More to come as projects continue...

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Paul Birkeland

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Reply #27 on: March 28, 2024, 04:51:09 PM
The green finish is a powder coating finish called fractured illusion apple, then the sides, front, and back are a caramel color.  This year I am doing a lot of projects themed in dessert color palettes.  A kit version of this would be squeezed onto a 10"x16" chassis plate which is the same size as the Kaiju and BeePre, though the option to go finished is certainly also possible.

There are other sizes and form factors in a finished product that we can explore which are a complete pain in the butt to offer as a kit, hence the possibility of two products. 
« Last Edit: March 28, 2024, 04:52:45 PM by Paul Birkeland »

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline sl-15

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Reply #28 on: March 29, 2024, 04:43:26 AM
This sounds all very interesting. I would be very excited about a Category 5. Good luck with this new project.

Stefan Hampel
Soundsmith Carmen, modded Technics SL-1200mkII, Thorens TD 125 mk2 with SME V, Eros, Extended Foreplay III, BeePre2, Crack, Pioneer Spec 4, Sonus Faber Electa


Offline Vitola B1

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Reply #29 on: March 29, 2024, 11:48:40 AM
The green finish is a powder coating finish called fractured illusion apple, then the sides, front, and back are a caramel color.  This year I am doing a lot of projects themed in dessert color palettes.  A kit version of this would be squeezed onto a 10"x16" chassis plate which is the same size as the Kike and Beeper, though the option to go finished is certainly also possible.

There are other sizes and form factors in a finished product that we can explore which are a complete pain in the butt to offer as a kit, hence the possibility of two products.

Hello Paul, thank you for the generous response, it is very pleasant to know the history of this project that is so loved by everyone, without a doubt the journey of this wonderful amplifier is admirable. Please, if possible, you can offer a version as a KIT, it would be great, since the full version is great but more expensive.

The prototype looks incredible, also the information in the newspapers and magazines on the wall.

Thanks to the entire bottlehead team for their work, Paul thanks for persevering as well as applying all the engineering for this job and thank PJ for his help in overcoming those challenges.
« Last Edit: March 29, 2024, 11:51:03 AM by Vitola B1 »