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A place to discuss member's DIY audio projects & post pictures/schematics. NOTE: There is a limit of 2MB per attachment, and a maximum of 3 attachments per message. If you need to post more than 3 attachments, just add another message.
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New Project - Direct coupled 845 SE amp.

July 12th, 2020, 4:33 pm

Haven't built his yet, but it's next up in the queue...
Image

Roscoe

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 12:44 am

Haven't I seen this at your house before.......minus a few tricks?

Do you still have enough quiet 5842 tubes to do this?

Where are you getting your grid chokes from?

This one's going to be mono-blocks, right?

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 7:57 am

Never saw a 100H choke.

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 8:09 am

Magnequest has a 100H/20mA choke, which I bet is what Roscoe is using.

David

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 8:14 am

A proper boat anchor builder would line up 10 Hammond 193M inductors. 10H 300 mh 63 ohms and a respectable 10.5 lb each.

ray

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 9:57 am

Roscoe Primrose wrote:Haven't built his yet, but it's next up in the queue...
Roscoe

Speaking of projects in the que -- did you ever build the tape-drive pre-amp you talked about? If you did -- how did it work out as compared to the stock electronics?

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 11:04 am

FerdinandII wrote:Haven't I seen this at your house before.......minus a few tricks?

Pretty much. The regulated driver supply is a new twist...

Do you still have enough quiet 5842 tubes to do this?

Yes. I also have >150 8532s, which could also work great with a bit more inductance in the plate choke. Might need to get Dave Slagle to wind me a pair if I go that route.

Where are you getting your grid chokes from?

They're plate chokes, Magenequest. Been in and out of the stereo 845 amp for quite some time...

This one's going to be mono-blocks, right?

Absolutely. I'm getting too old to schlep around a stereo 845 amp any more ;)

Roscoe

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 11:04 am

tomp wrote:Never saw a 100H choke.


But you've heard them ;)

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 11:05 am

ratbagp wrote:A proper boat anchor builder would line up 10 Hammond 193M inductors. 10H 300 mh 63 ohms and a respectable 10.5 lb each.

ray

Nobody's ever accused me of being proper ;)

Re: New Project - Direct coupled 845 SE amp.

July 13th, 2020, 11:06 am

SoundMods wrote:
Roscoe Primrose wrote:Haven't built his yet, but it's next up in the queue...
Roscoe

Speaking of projects in the que -- did you ever build the tape-drive pre-amp you talked about? If you did -- how did it work out as compared to the stock electronics?


Not yet. I did pick up a pair of late 60s Ampex solid state electronics, but haven't done anything with those yet either...

Roscoe
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