Though for years I have known about Mike "Magnequest" rediscovery of parallel-feed output transformers (his OPTs are the rage in Japan) which are the central modality of Doc Bottlehead's business, I have not experienced its unique aural matrix until now…sort of.

A long while ago I requested some amps from Doc Bottlehead with no response, and Mike seemed to be too busy to send me any of these unique output transformers with their matching plate chokes.

Six months ago Jim Dowdy Lama started to rave about his own custom made parallel feed amplifiers so I started to dialogue again with Mike, and asked him to create some custom OPTs for the KR PX-25…and I am still waiting and hope to have them in July/August.

My goal was to create an edge-shredding parallel-feed amp…a completely non-commercial meta-gizmo of gigantic coolosity.

In the meantime I discovered that Art Dudley, Chief Cheese of Listener, had built a pair of the Doc Bottlehead amps and was willing to send them to me…while I waited.


I am not going to bother telling you how scary this product is because you wont believe the cost of the kit for making two of these 2A3 amps. Check the Doc Bottlehead site yourself.

The performance you will get out of building these amps…which are without doubt is the best value in tubedom…is mind blowing…relative to the price.

Something completely unique is happening with this ancient output transformer concept in a modern format…which is why I will investigate it more seriously.

Trust me…there are some very sophisticated ideas implemented here, like active plate loading for the volt amp/driver stage.

Is this amp the most refined 2A3 amp I have ever heard? Not by a long shot, but they cost less than most pairs of silver interconnects…if you know what I mean. Do these amps have their own unique personality? What amplifier doesn't?

Can I think of a better "first" kit? NO!


In my upcoming idea I will tell the full story about Mike's magnificent obsessions.

He has reviewed an "magnetic coupling concept" that was developed when the Model A was considered a "hot" car. It is a simple idea of separating the "DC/loading" from the "AC transforming" into two separate magnetic device, rather than combining them in one SET OPT, (which is now normal) so that the OPT doesn't need an air gap..which creates a series of performance compromises in all SET OPTs. When you buy Mike's parallel-feed OPTs you get twins: a relatively tiny OPT transformer which handles just the AC, and a matching air-gapped plate choke for loading the output tube. You also need a fairly large capacitor (4 mfd) for blocking the DC from the AC transformer.

Does this modern implementation of a very ancient idea translate into a unique aural matrix? Do bears hug in the woods?


Go to www.audioasylum.com and click on the Doc Bottlehead bulletin board, (on the front page) and check out the support you get for using this product. This is the righteous way to deal with the public.



Doc Bottlehead is performing an important service by creating such high cost/performance ratio SET amps. YOU MUST INVESTIGATE THEM.

On the other hand there are some exotic ideas I have about Mike's miraculous gizmos that I feel compelled to explore…and much more will come soon.

What about a parallel-feed optimal aural matrix created with PX-25 on tweeter/midrange, and parallel-feed 300B on woofers…with no crossovers? Has anyone every created this before? Dear Lord, Why was I chosen to go where no audiomaniac has gone before?


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