Bottlehead releases an 805A monoblock amp kit

[BmWr75]

Is it just me or do the OPTs look small for a an amp with this power output?

Bottlehead Paradyne 805A Monoblock Amplifier Kit

Thirty-five watts of single-ended authority. Our finest design yet. Fifteen years of development have gone into this design, and you can tell. Built around the legendary 805A transmitting tube, Paradyne is the most powerful amplifier kit we have ever offered. At 35 watts per channel, delivered...

bottlehead.com

 

[vinylkid58]

Neat!

jeff

 

[Ken Boyd]

Look more like the chokes used on my amps.

 

[gadget73]

For single ended, yea they look small at that power level. Looks about right for push-pull.

 

[Selmerdave]

Aren't most Bottlehead OPTs parallel-feed and doesn't that reduce the required size?

 

[gadget73]

If it is, that would get rid of the DC problem and allow a smaller transformer for sure. To do that I guess you'd have to use a large plate choke to feed in the DC, and a cap to couple the AC over to the transformer? Only other way I know to do that is a resistor from B+ with the transformer coupled via a cap but that would waste a ton of power in the resistor.

 

[BmWr75]

Aren't most Bottlehead OPTs parallel-feed and doesn't that reduce the required size?

Don’t know. The only Bottlehead amp I’ve ever built was the OTL Crack headphone amp.

 

[zackthedog]

Probably parafeed.

 

[Duke58]

When I was still working at the national lab, I didn't dare access the Bottlehead website from work. Names such as "SEX and Crack" set off alarms from the computer support people.

Finally bought one of their preamp kits and wasn't happy that they didn't include the Bottlehead logo, I was supposed to pay for it.

But, it was a good start for getting into tube amps.

 

[Dave_in_Va.]

I think that amp looks really nice.
Are vintage good testing 805A tubes super expensive?

 

[zackthedog]

I think that amp looks really nice.
Are vintage good testing 805A tubes super expensive?

You'd be buying modern ones because they're made without the plate cap. Either way, vintage or modern, they're about the same as a new-made or vintage 845 or 211, depending on the brand.

 

[kward]

Very nice but ouch the price... Nevertheless, I'm encouraged the new owners are offering new high quality products.

 

[audiowize]

Yes, the output iron is a plate choke and a separate output transformer. The operating point of the 805A and the circuit design allow a far lower output transformer primary impedance than you'd typically find on an 805A amp, which also reduces the size requirement of the iron.

Saturation starts to happen at 31W/35Hz, so bigger iron didn't seem necessary.

 

[audiowize]

I think that amp looks really nice.
Are vintage good testing 805A tubes super expensive?

You can substitute vintage 838 tubes in place of the 805A. These are functionally identical in the Paradyne.

 

[BmWr75]

You can substitute vintage 838 tubes in place of the 805A. These are functionally identical in the Paradyne.

Just curious, what is you association with Bottlehead? Only ask because of your knowledge level about the new amp.

 

[lgdavis]

Is it just me or do the OPTs look small for a an amp with this power output?

Bottlehead Paradyne 805A Monoblock Amplifier Kit

Thirty-five watts of single-ended authority. Our finest design yet. Fifteen years of development have gone into this design, and you can tell. Built around the legendary 805A transmitting tube, Paradyne is the most powerful amplifier kit we have ever offered. At 35 watts per channel, delivered...

bottlehead.com

For $5,300 ?
UN-believable.

 

[Ken Boyd]

That doesn't seem unreasonable to me not for a pair of mono blocks.

And 35 watts SE that is quite powerful, many SE amp are usually very low powered amps.

 

[Ken Boyd]

I just wish they had covered the choke.

 

[Paul Joppa]

Just curious, what is you association with Bottlehead? Only ask because of your knowledge level about the new amp.

"audiowize" is my colleague, Paul Birkeland - and the principle designer of the Paradyne. :^)

Is it just me or do the OPTs look small for a an amp with this power output?

Bottlehead Paradyne 805A Monoblock Amplifier Kit

Thirty-five watts of single-ended authority. Our finest design yet. Fifteen years of development have gone into this design, and you can tell. Built around the legendary 805A transmitting tube, Paradyne is the most powerful amplifier kit we have ever offered. At 35 watts per channel, delivered...

bottlehead.com

You are right, they do look too small. But the 805A in the picture obscures part of the OPT, and the choke is hidden under the chassis plate,

I designed the plate choke and output transformer. Both are built on 2" stacks of EI-125 laminations (3.75" wide by 3.125" tall) and each weighs 6 pounds, so 12 pounds per monoblock.

 

[BmWr75]

"audiowize" is my colleague, Paul Birkeland - and the principle designer of the Paradyne. :^)

You are right, they do look too small. But the 805A in the picture obscures part of the OPT, and the choke is hidden under the chassis plate,

I designed the plate choke and output transformer. Both are built on 2" stacks of EI-125 laminations (3.75" wide by 3.125" tall) and each weighs 6 pounds, so 12 pounds per monoblock.

Thank you for chiming in Paul and Paul.