Search found 7 matches

by Red3
Sat Jun 06, 2020 6:16 am
Forum: Mark Series
Topic: Mark III with a Variac
Replies: 1
Views: 27

Mark III with a Variac

Has anyone run their Mark with a Variac? Or would that be bad?
by Red3
Fri Dec 27, 2019 8:11 pm
Forum: Mark Series
Topic: Mark III power tube break up - doesn't seem possible
Replies: 24
Views: 2210

Re: Mark III power tube break up - doesn't seem possible

I'm not the one that can give you all the tech insights, but yes you're right it seems the Mark series weren't designed for power tube break up. Biasing warmer might help. I know my amp tech put a bias adjustment pot in ( I think he replaced R117 or R102 with a pot), Mesa biases them very cold. Once...
by Red3
Sat Nov 09, 2019 6:42 am
Forum: Mark Series
Topic: Mark III Simul Redplating on two adjacent power tubes sockets (6L6 and EL34)
Replies: 3
Views: 757

Mark III Simul Redplating on two adjacent power tubes sockets (6L6 and EL34)

Mark III Red Stripe, Simulclass is redplating on two adjacent power tube sockets (6L6 and EL34). I've tried swopping out tubes same result. The plate current on these tubes runs very high (80ma). The other side (6L6, EL34) the bias is steady and in spec. Any thoughts would be great, thanks.
by Red3
Sat May 25, 2019 9:47 pm
Forum: Mark Series
Topic: Mark III Mods: R1 to R2/R3 Bass & Treble reduction & Increased Dynamic Response.
Replies: 0
Views: 1078

Mark III Mods: R1 to R2/R3 Bass & Treble reduction & Increased Dynamic Response.

This is an excerpt of a post on the "Mesa Boogie Mark lll Owners" FB Group, (amp tech based in Switzerland regarding his Purple stripe combo): I modified it a bit, less sharp trebly-ness as most blue stripe amps are, replaced all electrolytes just because they were 30years+ of age......nothing fancy...
by Red3
Sat May 25, 2019 9:43 pm
Forum: Boogie Board News & Announcements
Topic: This Forum is Awesome.
Replies: 0
Views: 1402

This Forum is Awesome.

Great Forum everyone. So glad I found this.

I'm running an '87 Mark III Red Stripe Simulclass hardwood Imbuya combo (EV12s, plus a 1xEV12s extension cab).
by Red3
Thu May 16, 2019 5:08 am
Forum: Mark Series
Topic: Mark IIC/C+ and III Power Section 1.5K Resistor Placement
Replies: 11
Views: 3166

Re: Mark IIC/C+ and III Power Section 1.5K Resistor Placement

I had already done a III+ mod with everything else identical to a IIC+, but left this 1.5K resistor stock until I made this discovery this week. I changed its placement in the power circuit of my III+ to be the same as the IIC+ this morning and noticed a massive change in sound! As in the amp is br...