Recent Posts

11

Kaiju Stereo 300B amp / Kaiju/ Beepre2 Equalizer

« Last post by blackharp on May 08, 2025, 06:21:11 AM »

Is there any way to integrate an equalizer, tone controls or similar into the circuit? If not, is there a cost effective hardware solution? I seem to be missing a bit of lower midrange and/ or fullness I get out of my Fisher and McIntosh amps on certain music. Jazz horns sound great connected to my Altecs. I know this is sacrilege to some. 

Thank you all in advance and as a side note, I just missed another crack sale. 

12

Moreplay Upgrade / Slightly high B+ Voltage?

« Last post by hmbscott on May 07, 2025, 03:23:28 PM »

Just completed my Moreplay Upgrade Kit install and have a slightly high B+ VDC value. I noticed it was rising with time initially but nearly stabilized after 10 minutes.

All voltages measured at 10 minutes after powering on except as noted:

My line voltage: 127.5 VAC
All LED's noted ON
"A" socket heater voltage: 6.28 VDC (measured on PCB at h2 + & -)
"B" socket heater voltage: 6.25 VDC (measured on PCB at h1 + & -)
Terminal 6: 135.9 VDC
Terminal 16: 138.7 VDC
B+ on PCB: 187.4 VDC

B+ with time
Minutes Volts
0 min    181.1VDC
2          185.4
4          186.7
6          187.2
8          187.4
10        187.5

I noted that the heater voltages were very stable between T=0 and 10 min.
Terminals 6 and 16 increased a few volts between T=0 and 10 min.

I'm assuming this is OK, but I thought I would run it past you.

13

Kaiju Stereo 300B amp / Re: Kaiju ground locations

« Last post by Dzrout on May 05, 2025, 08:44:44 AM »

Thank by you sir!

14

Mainline / Re: Mainline ten years in

« Last post by Doc B. on May 05, 2025, 08:34:23 AM »

I think the failure rate was actually a bit less than that. That studio amp had a rather flexible bottom cover, and at least once the failure was due to the bottom getting pushed in against the bottom of the biasing PC board. I remember it clearly because the repair was done in a big hurry in a hotel room at CES sometime in the 2000s. It shorted it out a second time when I set the case on an ottoman whose cushion pushed on the bottom and thus I got to do the repair twice and added a layer of insulating tape at the contact point. Luckily back in those days I brought a rolling tool case full of tools and spare parts to shows. In contrast the last Mainline I had went out on loan often and did many demos without ever breaking.

15

Moreplay Upgrade / Re: A few more kits available

« Last post by Love Rhino on May 04, 2025, 03:04:26 PM »

I was able to sneak into this drop as well, which makes me happy as I missed the last couple.  Shipping was super fast, thank you!

16

Mainline / Re: Mainline ten years in

« Last post by JamieMcC on May 04, 2025, 09:30:07 AM »

Thanks for the info that's great to hear.

I have a Hickok 600a Tube Tester (mind I've not turned it on for probably five years) I will see if I can find any test settings that might be suitable for the 6C45 tubes

17

Mainline / Re: Mainline ten years in

« Last post by Paul Birkeland on May 04, 2025, 04:59:52 AM »

Doc B. did the original build as a studio preamp/headphone amp ages ago, and the only part that failed (every 8-10 years) was the biasing device used for the 6C45.  We changed this for the Mainline somewhat by accident, so this may be a component that needs new tubes every 5-10 years and not much else for many decades. 

18

Kaiju Stereo 300B amp / Re: Kaiju ground locations

« Last post by Paul Birkeland on May 04, 2025, 04:57:50 AM »

The screw near the IEC power entry module, the central star ground point by the rocker switch, the four holes around each 9 pin socket, the holes where the trim pots mount (the metal body of those pots needs to contact the chassis), and the two screw holes by each set of binding posts. 

19

Kaiju Stereo 300B amp / Kaiju ground locations

« Last post by Dzrout on May 04, 2025, 04:51:07 AM »

I got my top plate back from the powder coder. Initial instructions were to only powder coat the top side. But he did both. 

What are the ground locations that I need to ensure are cleaned?

Anything other than the obvious?

20

Mainline / Re: Mainline ten years in

« Last post by JamieMcC on May 04, 2025, 01:39:58 AM »

Hi Paul yes still using the original 6C45 tubes (other than the 12au7) which was rolled simply to try about five years ago. Funny how time flies Its never even entered my thoughts that I'm still running on the original tubes must be thousands of hours on them so far as I have also used my Mainline for preamp duty Infront of a solid state power amp for many years as well as for headphones use .

I have acquired several new pairs of 6C45 tubes as well so looks like I'm easily covered for tubes for the Mainline to the end of my days.

Only thing I do is a bias check  every 6 six months or so if and when I remember.

Any thoughts on preventative maintenance/servicing I should  consider to keep things running smoothly or is it a case of don't mess with things if all working well for the time being?

Cheers