Something BIG is coming on Black Friday

[Paul Joppa]

Incidentally, the level controls are linear, not logarithmic - turning them down more than about 20dB would get twitchy, but for modest adjustments they are easier to adjust.

 

[Gerry E.]

They are level trims for each channel...

Could they be used as channel balance trim pots?

Also, if you are not concerned about noise level, would A/C heated filaments sound better?

Thanks!

Gerry   

 

[Paul Birkeland]

Could they be used as channel balance trim pots?

That is indeed their intended purpose.

Also, if you are not concerned about noise level, would A/C heated filaments sound better?

I am always quite skeptical about this.  We can say that the filament voltage regulation will remove filament voltage fluctuations if your line voltage wanders.

 

[Paul Joppa]

... would A/C heated filaments sound better?...

Only one way to find out - "...just listen!" as Bullwinkle says  :^)

We retain the hum pot, which if properly centered allows you to cancel noise or distortion generated in the DC supply. Jac at EML advocates this. You can find out if it's worthwhile in the same way.

 

[fullheadofnothing]

.

 

[kgoss]

Beautiful layout. I'm looking forward to building one this spring!

 

[ebag4]

Very nice.  Spacious layout, can't wait to get mine!

Best,
Ed

 

[Hank Murrow]

Finally a look at the underside: and assuming it is PB's work: "Congratulations!"

Cheers from Eugene, Hank

 

[Doc B]

Actually that is PBs build of PJs initial layout, and Josh sits in during the manual build and contributes a fair amount of good counsel on making the layout easily understood and built. It's a group effort. I walk in every few hours and ask if it's done yet.

 

[Natural Sound]

Well you should all be very proud. That's a very nice amplifier. One of the things I really like is that the filaments are AC heated. Which I believe sound better. Then there is an option to use a regulated DC supply if your system calls for that approach. Very nice indeed.

 

[sl-15]

That indeed is a very nice layout. Great work and congratulations to another kit. Could you tell me what the resistors are for that connect the speaker output to ground? Thanks.

 

[mcandmar]

Nice layout, love the symmetry. I assume the OT-5's the largest output transformers to date?

 

[Doc B]

That indeed is a very nice layout. Great work and congratulations to another kit. Could you tell me what the resistors are for that connect the speaker output to ground? Thanks.

That's something I suggested we experiment with a few years ago and liked. It's a balanced speaker output. Seems to tighten up the bass a bit in some situations.

Nice layout, love the symmetry. I assume the OT-5's the largest output transformers to date?

Yes. They new plate chokes and OTs add quite a bit of bass power handing compared to previous models.

 

[drewh1]

They are level trims for each channel.  They can easily be bypassed, or one could pretty easily install input transformers and change the input jacks to XLR's, but there are so many situations where you want 12-20dB of padding at the input of an amplifier that we have insisted on including them with the stock amp.

Are there any issues with bypassing the trims?  I am not using a pre-amp so likely do not need to pad.  Does it change the input impedence?

thanks

 

[Paul Birkeland]

Are there any issues with bypassing the trims?  I am not using a pre-amp so likely do not need to pad.  Does it change the input impedence?

You can turn them all the way up, which is as effective as bypassing them.