questions to HRM users...

[swt]

HI!. i've found that my hrm tends to sound a bit middy, and trace that to the 330pf when boosted with pab and hrm stuff. do you think it's a good choice to raise that cap a bit from 330p to 500 or even 1nf to get more bass on the front end, and then use the trimmers to take some bass out at the output??.
i use a mid boost with a relay whenever i use the pab in the non hrm amps i have, so just checking if that's a good choice in this amp too. thanks for any replies!!

[Bob-I]

HI!. i've found that my hrm tends to sound a bit middy, and trace that to the 330pf when boosted with pab and hrm stuff. do you think it's a good choice to raise that cap a bit from 330p to 500 or even 1nf to get more bass on the front end, and then use the trimmers to take some bass out at the output??.
i use a mid boost with a relay whenever i use the pab in the non hrm amps i have, so just checking if that's a good choice in this amp too. thanks for any replies!!

My HRM's are FAR from muddy. What cathode bypass caps do you have? I use 5uF - 5uF - 5uF then 1uF on the final to take away some of the bass. Then adjust the HRM to give you a nice balanced tone.

[Icetech]

Middy.. not muddy:)

[ampdoc1]

My last build (not a "pure" dumble) did the same thing when the PAB was engaged. I moved the relay connection to switch the 10k bass resistor to ground or open. When engaged (ground connection open) I found the boost volume was too great, and finally installed another resistor between the 10k resistor and ground. I experimented until I found a value that gave the boost the level I wanted. It is much less "middy" + i got the amount of boost I like.

ampdoc

[swt]

thanks for the replies. i'll try that doc. Mesa do it that way too. i'll report back with the final results.