HH Scott 299 Phono Channel Left Side Intermittent

[reverend13]

Hi all -- I have a Scott 299 that has been having problems with the left side intermittently going quiet but coming back on. Only occurs on the Phono channel, as I do not have this issue on the Tape channel. No crackles or static when this happens.

• Connection with the speakers are good.
• Used Deoxit on the RCA inputs to clean, and the same problems exist

Given the Tape in works great, could this be a problem tube with the Phono input?

I'm also using a newer Rega RP1 w/performance pack as the TT -- I guess it could be a loose/bad connection there as well?

Thanks in advance!

 

[Patrice B]

Is your amp up to specs? I mean recapped, sockets and switches cleaned, tubes checked? You could try to swap the two phono tubes (12AX7's front left if I'm not mistaken).

edit: ok, tape is working so the tubes should be healthy. Could be the selector switch...

 

[911s55]

Clean your slider switches and pre amp tube sockets. Wiggle your 12ax7 preamp tubes to see if you can isolate the issue, crackle crackle etc. Low volume BTW.

 

[reverend13]

Thanks guys. I'll do some cleaning around the sliders and tube sockets. I have a feeling it might be the preamp tube but will know more once I fire it up again tomorrow.

 

[GordonW]

Also worth a try, to reverse the left and right RCA cables from the turntable into the amp. Might as well rule that out...

Regards,
Gordon.

 

[kvflyer]

Slide switches are notorious for causing that problem. Did you "wiggle" them? Sometimes the Tape Monitor switch (if your version has one) can give you issues.

 

[Diverted]

This was exactly the problem with mine. I was getting intermittent volume out of Channel A in a freshly recapped 299B and tracked it to the monitor switch. Cleaned it up and so far so good, Channel A's back.

 

[derwin424]

i am having a similar problem but with right channel, also phono 1 and 2. The right RCA terminal does not hold the RCA jack in well. Anyone tried replacing the RCA terminals?

 

[Patrice B]

i am having a similar problem but with right channel, also phono 1 and 2. The right RCA terminal does not hold the RCA jack in well. Anyone tried replacing the RCA terminals?

Deoxit in jacks and switches? You could also probably replace the RCA jacks with modern ones but I never had to it on any of my old hifi tube amps.

It’s another story with my musical instruments tube amps 1/4 jacks however…

 

[Dadbar]

I have a 299. Scott used the cheapest quality slide switches on these units. Unless you REALLY need the ability to run 2 turntables, I would advise you to jumper across the slide switches for both channels and just use one of the inputs. Otherwise you will be "Deoxiting" until the cows come home. I would also advise you to remove the phase reversal switch and likewise jumper the rumble and noise filters too.

 

[Wickateer]

Hey reverend13 - did you ever fix this issue? Do you remember what you did? I have a similar issue with the smaller, simpler HH Scott 200. Right channel drops intermittently, only happens in phono (tuner works fine with no drops). I just put in three new matched 12AX7s thinking it might fix the issue but no change. I think I will try cleaning the slide switch from phono to tuner next.

 

[reverend13]

Hi - I did. I’ve also come a long way since I posted this and have resurrected a few non-working HH Scott’s since then thanks to AK’s help.

I’d try swapping the phono tubes currently in there, i.e. put the one currently on the right channel to the left and vice versa. If the same side is still intermittent, could be beyond a tube issue. Maybe the tube pins need to be retentioned, maybe a bad capacitor. Might even be dirty switches where a light spray of Deoxit could help. My first suggestion would be to swap the tubes with one another to see if the problem stays in the right channel or if it moves to the left.

 

[Wickateer]

Thanks for the tips reverend13. I did swap around the pre-amp tubes and then replaced all three. By playing with the Selector switch, I was able to learn that the issue was not in the power tubes, as the right speaker had no issue with the left channel input. Playing with the slide switch from Tuner to Phono, it is clear that is where the issue because when it drops out, I can wiggle the switch to get the right Channel to come back, without sliding all the way to Tuner. Now I need to figure out the best way to clean the switch. I have never taken the faceplate off. Using Deoxit (D5, followed by F5 and lots of switching back and forth) with the facepate on did not do the trick.

 

[reverend13]

I would only use a little deoxit on the switches and F5 on the pots. I think it’s best to take the faceplate off so you can spray inside a hole into the switch cavity with the stir straw. Maybe when spraying from the front with the faceplate on, some of the solution may seep into the switch chamber but it’s uncertain. If you’re uncomfortable doing this, then perhaps take to a tech.