Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: emerson909 on March 15, 2025, 05:21:35 pm

Title: Marshall JCM 2000 TSL 60 to JCM800 2204
Post by: emerson909 on March 15, 2025, 05:21:35 pm

Here’s some details of my latest project, I got a TSL 60 and converted to a 2204 using Merlin’s universal PCB’s. Big thank you to Merlin for making the designs available and all the info on your website! The chassis looks a bit like Swiss cheese after removing all the TSL nonsense but other than that it’s been a straightforward conversion, sounds awesome!

Title: Re: Marhsall JCM 2000 TSL 60 to JCM800
Post by: emerson909 on March 15, 2025, 05:22:52 pm

Pictures

Title: Re: Marshall JCM 2000 TSL 60 to JCM800 2204
Post by: emerson909 on March 15, 2025, 05:29:06 pm

PSU Board

Title: Re: Marshall JCM 2000 TSL 60 to JCM800 2204
Post by: emerson909 on March 18, 2025, 07:10:52 am

oops, spotted my first mistake, I'd overlooked the voltage divider values for the heater elevation, consequently I've had around 120V.

Will change R604 to 270K which should give me 50V, will also swap out the 100V rated C604 incase I've cooked it

Title: Re: Marshall JCM 2000 TSL 60 to JCM800 2204
Post by: Willabe on March 18, 2025, 09:10:33 am

On your voltage divider, your wasting some heater current.

I'd change the 33K R to 100K, don't go higher than that. Then readjust the other R. Merlin writes 30 dcv to 60 dcv is common, Kevin O'Connor likes 70 dcv to 80 dcv.

Read this from Merlin on heater supplies, go down to heater elevation;

https://www.valvewizard.co.uk/heater.html (https://www.valvewizard.co.uk/heater.html)