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Message started by Radarek on 12/01/20 at 00:45:26

Title: Heathkit Ua2 mods
Post by Radarek on 12/01/20 at 00:45:26

Hi

Just got a set of nicely preserved set of monos Ua2. Some of parts were upgraded, but no mods were performed to the circuit itself. As am waiting for new set of tubes for it, some ideas were born...Here is my question... as this is EL 84 powered amp... would the Hazen mod be a nice upgraded together with 6p15p tubes?? If yes what else would need to be done with the mod to go through?

Can post schematic if that helps

Thanks

Darius

Title: Re: Heathkit Ua2 mods
Post by hdrider on 12/20/20 at 16:49:19

Radarek- I am not the one to comment on your questions, other than to say I am interested in what the outcome will be. I have a Rachael and do like the EL34 and it sounds very good as it is. But, I really love it with 807's and adaptors. How do the amps sound as is? I remember having a set of McIntosh MC30's that I bought off a customer in the late 80's. Worked fine, looked good but sounded like ''classic'' tube amps. Glorious midrange, low bass was like over cooked pasta and the top end was ok but always sounded to me a little ''phasey''. Keep us posted on your adventure and some photos would be awesome. Happy listening, Chris.

Title: Re: Heathkit Ua2 mods
Post by 4krow on 12/24/20 at 17:09:35

Since the Hazen mod was done to my Rachel, I must point out that these use an EL34 tube rather than an EL84 tube. Having said that, my question would be about the makeup of the tube itself, i.e. an EL34 tube is a triode, but I don't recall if the EL84 tube is also a triode. If not, then the Hazen mod may very well not apply here. It has been awhile since I have been on this site, so forgive me if I have missed something.

Title: Re: Heathkit Ua2 mods
Post by Lon on 12/24/20 at 18:06:57

If I recall correctly the Hazen Grid Mod does not work with the EL84, but does with the tubes Steve supplies the 6P15 type.

Title: Re: Heathkit Ua2 mods
Post by Radarek on 01/20/21 at 00:38:56

Hi

Whole idea was about using 6p15p tubes. Standard Ua2 is working perfectly with them installed...just want to squeeze that extra bit...