Mainline version history question

[Rossputin]

Hello all,

I assume that version 1.1 of the main line is some kind of upgrade or update over the original.

First question: is that correct or was the first one called 1.1?

Second: If it is correct, is there a place where I can see what the changes were between the original and the 1.1?

Finally: What's your opinion about the relative value of the two if I am looking to buy a preowned one?

Thanks in advance for any help!

 

[Paul Birkeland]

The 1.1 update allowed us to substitute the separate 120V and 240V power transformers with one part that could be wired for those voltages and several others.  We also slightly tweaked the power supply PC board and took the opportunity to update those build photos to reflect using leaded capacitors rather than the older snap-in caps. 

Otherwise the rest of the build is the same.

 

[Rossputin]

Thanks, Paul, that's VERY interesting.

If I buy one of the originals I will listen for a good amount of time before considering any mods and I know you've said on the forum in the past that the Mainline really isn't a product that wants/needs many mods or upgrades but my question for you is: if you had version 1.0 with no upgrades what, if anything, would you update/upgrade?

Thanks again!
Ross in Denver
(Crack/Speedball owner right now, probably moving to Mainline as I get some high-end headphones)

 

[Paul Birkeland]

You could swap out the 10uF parallel feed caps for some 20uF V-cap ODAMs.

 

[Rossputin]

OK, and is it obvious in the manual or elsewhere which are those caps that you're saying I can upgrade? Or possible for you to post a picture with the specific cap circled?

 

[Rossputin]

Hi Paul,

Looks like V-Cap ODAM come in 18uf and 22uf.

Which would you use, and are there other caps that you think are nearly as good but a lot less expensive?

Thanks again!

 

[Paul Birkeland]

Not particularly.  If you're going through the trouble and upgrading about the only parts in the amp that can be swapped out, go big!

 

[Rossputin]

I like that philosophy. Can you help me make sure I'm looking at the right parts to swap? Are they the big 10uf Dayton film caps just forward of the OT-3 transformers on each side? And should I go with 18uf or 22uf in V-Cap? Are V-Cap that much better than the various Mundorf lines? I REALLY appreciate your input, Paul!

By the way, I talked about Bottlehead products on my radio show today!

 

[Paul Birkeland]

Either 18uF or 22uF, whichever suits your fancy.  Yes, they replace the 10uF caps.

The Mundorfs that would make sense for the circuit are oddly shaped and aren't likely to fit all that well.

 

[Rossputin]

Hey Paul, I haven't checked the physical dimensions yet as far as fitting in the Mainline but other than that what do you think of these? (They're 50% off right now...much cheaper than ODAM at the moment.)
https://www.v-cap.com/oil-capacitors.php

 

[Paul Birkeland]

The voltage rating is insufficient.

 

[Rossputin]

gotcha...what's minimum voltage rating we need?

 

[Thermioniclife]

250v or higher.

 

[Rossputin]

OK, one more cap question: Opinion of Clarity Cap CMR (I know they're large) vs VCap ODAM?

 

[Paul Birkeland]

Way too big to fit the space.

 

[Rossputin]

You talked me into it, Paul...My VCap ODAMs arrive today. I went with 18uf because I found them MUCH cheaper than the 22uf, and there's no 20uf. Hope that's gonna be fine.

Do you know if the 6C15P tube is a drop-in replacement for the 6C45PI? I like using tubes from the year I was born and I don't think the 6C45 was made in the 1960s. I'm having a hell of a hard time finding out if there's a nearly identical replacement that was made in the 60s. This 6C15P seems like the only possibility but I just can't find out much about it.

 

[Paul Birkeland]

When this last came up, I don't believe I was able to find much in the way of a datasheet, but I believe they will work.

 

[Rossputin]

how much risk do I have if I put one in and it's not actually a perfect substitute? I have a feeling it's more risk than I'd want to take.

 

[Paul Birkeland]

The Mainline is current regulated, so catastrophic damage is generally unlikely.  If the pinout is the same but the tube isn't electrically the same, the most likely negative result would be bad sound.

 

[Rossputin]

Paul, this is how you know it's gone too far:

Last night I had a dream that you said (in a posting on this board) that the transformer in the Mainline could/should be upgraded so I woke up this morning thinking I needed to go research potential replacements. And I was kinda excited about the prospect.

What does that say about me?

And why did you say to upgrade the transformer?