New To Me Paramounts

[brucef]

Just purchased a used pair of Paramount 300B amps. Hooked them up and there  does not seem to be any issues with them. Couple of questions: what is the potentiometer for on each amp? And it seems like my current system with the Paramounts sounds kind of harsh and fatiguing. I have a Quickie pre hooked to the Paramounts that I have had for several years that I have used with no issues. Speakers are a pair of diy speakers at around 96db efficiency. They are single full range drivers in a ported cabinet. Prior to the Paramounts I was running a 1965 Fisher X-100 integrated that has been rebuilt. That Fisher setup sounds very very good. So, I am wondering if perhaps the Quickie is a bad match for the Paramounts or perhaps tubes?? The 300B tubes are Electro Harmonix and there is not a name on the 5670 tubes. I believe the Paramounts are stock builds. Looking for suggestions before I start spending money trying to smooth out the sound of these mono blocks.

[kgoss]

If they are stock, the potentiometer on each amp is used along with a meter to adjust the DHT hum of the 300B to the lowest value.

[Paul Birkeland]

I would post photos of the top and bottom of the Paramounts, as there are some mods that may need to be undone. 

How fresh are the batteries on the Quickie?

My experience with vintage Fisher gear is that when you pile up 12AX7s, the high frequencies soften considerably.  If you happen to have full range drivers that have rising response, the soft high frequency response of the Fisher may counteract the rising response of the speakers. 

It's a lot of speculation without more details.  Dead/dying tubes will also sound really harsh, but I wouldn't be running off to buy new ones until you test the ones you have.

[brucef]

Thanks for the responses. I will try new batteries in the Quickie to see if that helps. I am assuming that the Quickie should play well with the Paramounts. Here are some pictures of the amps. I am not really familiar with the 300B tube. Can it be tested ona standard tube tester. This is all new to me. Thanks

[brucef]

More pics

[brucef]

more pics

[brucef]

More pictures

[brucef]

Checked the batteries in the Quickie. The 9 volt batteries test at just under 8 volts and the D batteries test at just under 1.3 volts. Good enough or change?

[oguinn]

I work off this thread, where PJ calls the D cells "tired" at 1.2 volts and has the 9 volts operating between 24-36v.

https://bottlehead.com/smf/index.php?topic=5241.msg50532#msg50532

[brucef]

Thanks for the battery info. Another question I thought of is how long do those mono blocks need to warm up?

[Paul Birkeland]

Everything looks bone stock and well built on the amps, so that's a good start.   The amps will take about 30 minutes to warm up.

[brucef]

Thanks. Good to know the amps are stock. How do I test the 300B tubes? I do have a couple of tube testers, but I did not see any info in the charts to test 300b tubes.

[Doc B.]

If they pull the correct voltage in the amps they are testing good. This is just as good a test as using a tube tester.

[brucef]

Thanks Doc. But I have no idea where to begin to test the voltage. I did find info that said to set the tester for the specs of a 2A3 tube, but set the filament voltage on 5 volts. Doing it that way the 300b's tested in the good range and the 5670 tubes tested strong. I listened again last night and to me, they sound thin, harsh and not much low end. Either something is amiss or it is just the nature of th amps?? This is my first experience with 300b amps. Or I am wondering if the Quickie pre is a bad match with the Paramounts. I have always used the Quickie with a ss amp and that combination was very good. After listening for a while I shut things down and hooked the Fisher back up to the same speakers etc, and it blew the Paramount Quickie combo away. Unfortunately I just recently sold a couple of pre amps and don't have anything else on hand to try with the Paramounts at this time. Sigh. Nor sure were to go from here. Any help is greatly appreciated. Thanks Bruce

[Paul Birkeland]

Did the seller not include the manual? 

Have you left them on for several hours to get them warmed up?