New Octal Build

[fusionbear]

Still waiting for my chassis. But, I made a drawing of it and have a proposed layout. What think ye? Any concerns? The PT and Choke are Hammond.

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0751_zps1io2dps4.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0753_zpscnpbzkxe.jpg[/img]

The brass plate is just to help me align the controls... I am going to use those knobs...

[RWood]

What's it based on? Your own design?
Always curious about what's coming out of LaHabra next.

Edit: Never mind...Just saw your earlier post on Express type Octal.

[Stevem]

I have found that sometimes, not allways, but the new manufacture Sovtek octal's can sound like crap when pushed to clipping,much like Sovtek made output tubes in general when pushed hard!
I would say to at least dump the Bucks into a NOS octal for the PI section.

I would think about not using a multi section can filter like that silver one also so you can get the filter node grounding in a better way for minimal 120 hz hum and if need be make it easyer to fine tune the uf value for the first gain stage power supply feed.

Will the output stage be cathode biased?

[fusionbear]

I have found that sometimes, not allways, but the new manufacture Sovtek octal's can sound like crap when pushed to clipping,much like Sovtek made output tubes in general when pushed hard!
I would say to at least dump the Bucks into a NOS octal for the PI section.

I would think about not using a multi section can filter like that silver one also so you can get the filter node grounding in a better way for minimal 120 hz hum and if need be make it easyer to fine tune the uf value for the first gain stage power supply feed.

Will the output stage be cathode biased?

I have some nos Tungsol's for the pre's. I have NOS Mullard EL34's and some NOS Sylvania 6L6's to play with. I probably will not use the multi can cap for the preamp filtes. I have some nice USA Made Axial caps I have been saving that I most likely will use. Definitely Cathode biased.

[V2]

perhaps consider rotating the PT or the OT (even though they are on opposite sides of the chassis).

Which Hammond PT model is this?

[fusionbear]

Here is the progress I made yesterday and today. Punched, drilled and painted yesterday, started assembling today:

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0759_zpsky9cquqq.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0760_zpsk2htkufw.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0771_zpsrfiyvtpx.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0777_zpsgb9gpvuy.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0778_zpsb7wknqqv.jpg[/img]

[TUBEDUDE]

Nice clean build! Are those custom made turret strips? I hope to hear some sound clips when you are finished.

[fusionbear]

Nice clean build! Are those custom made turret strips? I hope to hear some sound clips when you are finished.

They are generic ones. I bought them here:

https://www.tubesandmore.com/products/P-HTUR-STRIP-23

https://www.tubesandmore.com/products/P-HTUR-STRIP-12

If it sounds good, I will post a clip, definitely.....

[V2]

I like the heavy-duty cathode R mounted to the chassis for heat dissipation. Costs more, but worth it! Nice touch, Carl.

[dorrisant]

I just used those same turret strips in a Hoso 56 build... Love 'em!!

Nice looking build!!!

Tony

[fusionbear]

A little more progress...

On the home stretch now, but I won't get to work on it next until Thursday or Friday...

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0785_zpsbdxx0ovf.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0786_zps4oxc5fmn.jpg[/img]

[V2]

What do you use as sleeves for your component leads? Heat shrink, spare jackets from your wire, or something else?

[fusionbear]

What do you use as sleeves for your component leads? Heat shrink, spare jackets from your wire, or something else?

I buy teflon insulation. It comes in different colors and different gauges. 22, 20, 18, etc... I use Black and Clear.

I buy it at my local shop: Ford Electronics in Fullerton, CA. But, it should be available at all the usual places like Mouser, Digi-Key, etc...

[fusionbear]

Well, my schedule changed and I finished the amp this evening. I only had to modify one resistor in the B+ string to get it where I wanted it. The amp sounds better than I would have imagined and is quiet as a church mouse, well, unless, you have it maxed out... Also, I went back and forth between my NOS Mullard EL34's and Sylvania 6L6GC's. The Sylvania's won. They just sounded fuller, richer. The Mullard's were a little thinner sounding than the Sylvania's. I will let the amp settle a little bit before making a clip. Now, I have to sell some stuff to afford a head box... The chassis is a JTM45 type, so I am not sure which one I will get. Also, I would like some reco's on what tolex, maybe even tweed?

Here is Samson!

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0809_zpstpcdyvre.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0804_zpsvsq0jmco.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0795_zpsjochhqud.jpg[/img]

I ended up changing the gain knob to the smaller size. Obviously, the MV is a PPIMV. Lar/MAR Style.

The tone stack is from Merlin's Preamp book, page 240 first edition. James tone stack with mid-shift. No standby switch.... (I hate those things....)

[Structo]

Real nice Carl!