5F6-A builders

[Mars Hall]

I'm interested in knowing what B+ voltages you getting from the PT. Include which rectifier is being used and if possible what voltage the PT is giving the recrifier.

The info will be useful in determining what PT I will use for my Bassman RI conversion. The stock PT puts out higher voltages than what the originals did. The typical RI puts 374v to the rectifier which equates to about 470v-480v B+, with a GZ34 rectifier. My target is 440v. Thank you very much.

[M Fowler]

The specs are 117v/60hZ 650vCT 200mA, 6.3v 3A, 5V 3A

325-0-325

The OT is 4K 4 ohms 50w rating.

I used from www.tubesand more.com PT290DX and OT Bassman reissue for 59 bassman P-TF36485.

325vac rectified 470dc and 465 pin 3 and 460 pin 4 (6L6)

Mark

[Andy Le Blanc]

with cathode bias the opt should be a bit higher 5-6K

[Mars Hall]

The specs are 117v/60hZ 650vCT 200mA, 6.3v 3A, 5V 3A

325-0-325

The OT is 4K 4 ohms 50w rating.

I used from www.tubesand more.com PT290DX and OT Bassman reissue for 59 bassman P-TF36485.

325vac rectified 470dc and 465 pin 3 and 460 pin 4 (6L6)

Mark

Thank you Mark, that PT from AES is one that I've been considering. Those voltages are close to what guys, over at the FDP forum, are getting with the stock PT. Still waiting on my amp to arrive, once I get it, I'll see what I've got and go from there.

Shouldn't the OT provide a 2 ohm load?

[M Fowler]

The 2 ohm verses 4 ohm depends on your speaker ohms and how you wire them series or series parallel. But yes that is one thing you should figure out first. I see no reason with going between 4k to 6k OT in that range and Andy just said the he was thinking the 5k to 6K range but my data has it starting at 4k so (who) knows.

Mark

[Mars Hall]

On the sublect of OT's, I thought I might try this one from Magnetic Components.

http://classictone.net/40-18007.html

Has anyone tried them? What OT do you suggest?

[Jana]

Andy was suggesting impedances for cathode bias, the 5F6a is fixed bias.

[M Fowler]

Thanks Jana, yes it sure is fixed bias.

Mars Hall, the Magnetic Components trannies are good and used by many. I sure enjoy their pricing.

[Mars Hall]

Depending on what the stock PT puts out, looks like I'll go for the Hammond. It's rated at 352v-0-325v at 200ma. I'm defintely gonna give the Magnetic Components OT a try. Thanks everyone for your input. Still, would be interested in seeing more "real world" example PT B+ voltages.

[M Fowler]

You want me to measure my dropping string on my bassman? I can do that.

Here is the 5F6a I built using ebay cabinet, mojo chassis and sourced parts. I didn't want to go with eyelet board and put the filter caps in the large available space inside the chassis rather under a cap cover on top.

Mark

[Mars Hall]

Mark, that's a nice looking build. Is that a Hoffman board? I like working with turrets better than eyelets too. So, what PT are you using and what plate voltage do you have there?

[M Fowler]

Thanks,

Its a tight fit inside that chassis but worked rather well putting the caps on turret strips. The board is from http://turretboards.com/ and the trannies I noted in the above post.

I used from www.tubesand more.com PT290DX and OT Bassman reissue for 59 bassman P-TF36485.

I will take some readings for you right after I button up my Normster Rocket Reverb build I finished this morning, great amp.

[Mars Hall]

Thanks,

Its a tight fit inside that chassis but worked rather well putting the caps on turret strips. The board is from http://turretboards.com/ and the trannies I noted in the above post.

I used from www.tubesand more.com PT290DX and OT Bassman reissue for 59 bassman P-TF36485.

I will take some readings for you right after I button up my Normster Rocket Reverb build I finished this morning, great amp.

Very cool, Thank You! I was looking at the Weber boards, they have a kit that comes with the fiber board, brass grounding buss with the smaller cap board. That's not a bad idea you have there with the caps inside, I may have to rethink that.

Curious, did you use a brass gound buss like Fender or a wire buss ala Marshall?

[M Fowler]

No I did not use a brass plate but probably not a bad idea that you have going with Hoffman stuff. Make your own design and run with it.

Back to the bench.

[Cliff Schecht]

Are those Groove Tubes I see in there?

*Throws up a little in mouth*