My Paramount experience

[johnsonad]

So far I

[Paully]

Just on a side note, it sounds like you are into tube rolling, I really have enjoyed my Shuguang 300B-98 tubes.  Even more than the EH, so something to tuck into your bonnet for consideration.  Compared to what you have spent they are cheap so maybe worth a try.

[johnsonad]

So far so good.  The EH 300B Gold Grids didn't work well in my system to my ears, too much treble.  Almost as if they had a 9dB boost on them which prevented me from turning up the volume and thus a loss of bass.  Picked up a pair of TJ300B mesh ST's from DIYHi-Fi supply.  They only have 10 or so hours on them and I'm much happier.  No treble drilling holes in my head.  Smooth sounding, great imaging etc...  Brian is good to work with at DIYHi-Fi (I have no affiliation with them) and he matched them up with a curve tracer after a few hours of burn in.  I can't tell if this made a difference but they sound great with my 19's. 

I still feel that the Paramounts are bass shy but it could be an impedance issue.  It seems that they had more bass at some point but that was before new iron and such.  I'm using 4uF caps for parafeed and I seem to remember PJ saying that changing this value can have some effect on impedance. 

Next project will be rebuilding the crossovers for the 19's which will change things once again.  The parafeed caps can wait as right now I'm pretty happy. 

[johnsonad]

In the end it's all about the personal listening experience and with my Altec Model 19's, the Paramounts couldn't give me everything I had hoped for.  I'm thankfull for the time with these wonderful amps and to the stellar Bottlehead team in support of them.  They will hopefully find a new home shortly.  Thankfully they will not be the last Bottlehead amp in my system

[Paul Joppa]

Just a thought - if you still have the original 3.3uF parafeed caps, you could use them in parallel with your 4uF Russian oil-filled caps to get 7.3uF. Not that that's an optimum value, but it will give you some information on the effect of that capacitor on the bass.

In my experience, the nickel core transformers are as you say much cleaner, but they are also more sensitive to bass overload if driven hard. If the bass is only limited on loud passages, it may be that the 8 watts does not provide enough headroom in your system. Just something to keep in mind as you continue the pursuit!

[johnsonad]

Thanks Paul.  I've got a pair of 5uF Auricaps I may throw in once the soft start boards come out and a pair of 6uF oilers to try also.  I picked up a direct coupled 2a3 amp and the bass is much better than with the 300B Paramounts in the configuration as stated in this thread.  The stock iron is back in the Paramounts and once the new boards are here, will switch it over to 2a3 for comparison with the other amp. 

[Grainger49]

With as many different value capacitors as you have I would attach a pair of alligator clip jumpers to the Parafeed cap on each and roll through some caps in parallel as Paul suggests.  You have a good selection of values to determine if the total value changes the bass characteristics.

I'm guessing the stock 3.3uF are gone.

[johnsonad]

Time for a short update.

The soft start kits are in as is the Magnequest iron,  5uF Auricaps and they are converted for 2A3.  Hopefully the caps follow the path as Steve and others have said; they end as well as they start out.  Spent a couple of hours with them in the system before setting them up for burn in with the new crossovers for the Altecs last night.  Started with the stock GE 5670 (that came with the soft start kits) and Sovetek 2A3 tube complement.  From the beginning I liked the sound more than the 12AT7/300B.  Not sure what the problems were (probably the Russian caps) but the amps as set up before didn

[johnsonad]

I've got enough time on the amps to make a few observations.  The Paramounts are set up for 2A3 using Magnequest iron, 5uF Auricap and the soft start boards (Bottlehead power cords too).  They were burned in 130 hours (had to stop due to the continual earthquakes here in Japan) then put back in the system.  I spent two days with an older pair of Sovtek 2A3's (burn in tubes) and the stock 5670's.  Today I replaced the Sovtek's with a pair of EML mesh plates that have been patiently waiting.  The EML tubes were simply transformative and really show what the Paramounts are capable of.  I

[pro_crip]

I got those eml's waiting too, as well as the mq all nickle upgrade option. I figured I'd burn in the system stock first and then add the soft start, upgraded iron and emls in steps to see what each does to the sound. I've already decided to use pure silver as pathway wiring. Thanks for sharing.


Rich

[Jim R.]

Aaron,

Congrats!  Sounds like a lovely combination you are running there.  Did you try those ericsson/siemens 2c51s yet?  My guess is that they will take things up yet another notch.

Best to you and everybody else in Japan who is dealing with this diaster.

-- Jim

[johnsonad]

Hi Jim,

If you find an extra pair of those tubes, let me know!  They seem pretty slim pickings.  I haven't rolled the drivers yet as I'm trying to get a sonic feel for the amps first.  There has been so much change in the system lately it's hard to pinpoint what's making the improvements.  I am putting in an order for different plate chokes and intend to increase the parafeed caps to 10uF.  After the amps have burned in I'll start to roll tubes and post the results. 

We are doing our best here in Japan.  Other than the blackouts, Yokosuka is doing okay.

Regards,

Aaron

[johnsonad]

Tube rolling.  I love and hate it.  So many flavors but which to choose?  Like an aged wine, they do improve with break in (air) and I've been a tube-ohlic rolling before given them proper break in.  The best sounding to my ears and taste so far are the stock GE 5670 that came with the soft start kits and happen to be the only pair with more than 8 hours or so on them (100+).  They may not excel in the low end but they have a way with the top end that the others so far haven't touched.  It would be nice to have a burn in rig for this tube as my patience seems to be limited and I hate to waste hours of the EML mesh plates life with break in.  The plan so far is when the new plate chokes and caps get installed I'll rotate drivers every day until they all get rotated through with a pair of Sovtek's.  So far the list includes:
1. GE 5670
   A. 5670W (79)
   B. 5670W (88)
   C. 5670 5 Star (unk)
2. Bendix 6385
3. WE 396a (5 or to play with, can't figure out their date codes)
4. JW WE 396a
5. Tung Sol 2C51
6. Raytheon 5670 (mil spec)
7. RCA Command 5670 (60's, double and triple mica)
8. 6N3P-DR
9. 6N3P-EV
10. CBS 5670 (bulk pack tubes, not the greatest build quality)

The WE's in my stash have not worked out so well thus far.  A couple are used tubes and I found one that wouldn't bias.  Paul believes it was a weak tube.  The older tubes I've tried so far need time to bias up right. I'm going to try leaving them in the tester to warm up some before trying them in the amps.  Tube dampers on the driver have made an audible difference with some tubes.  Most of mine are double mica without extra support rods. 

Also on the plate is a pair of Triad C7-X chokes for the power supply.  Though they may only make a small difference if any, they are a cheap upgrade and easy enough to reverse.

More to follow

Aaron

[dw]

I also have the soft start up and running. Ran the Sovtek 2a3s for about a day and then put in a pair of EML mesh plates.
I have about 7 hours on the EMLs and they sound quite good, I think better than the Sovteks. Seems like more detail in the music.

One time when I powered up the EMLs, one channel was much softer and thinner than the other. I powered down, waited the 20 minutes,
and replaced the EMLs with the Sovteks. Powering up all was good. Powered down, waited 20 minutes, and put the EMLs back, this time switched
between the amps. Powered up and all was fine. I don't know if this was a tube socket contact issue, or what. The last 4 or 5 power cycles on the amp have
been fine.

I'm using 105db LaScalas and the first click on the foreplay III is medium loud and the second click is my-wife-asks-me-to-turn-it-down loud.
Time to put the voltage divider on the input that folks here helped me with back in.

I have a pot as a voltage divider now. It's one that Grainger or Caucasian Backplate recommended. I also used PJ's paper on noise.
As I get the pot set right, is it worth replacing it with high quality fixed resistors?

Thanks,
Dave

[johnsonad]

Hi Dave,

I've found that the EML's change some with break in though I'm not sure if this is the parafeed caps finishing up or something else in the system.  The EML's have greater bass at this point and can sound very realistic, almost scary at times depending on who is singing.  They are one of the better investments I've made in the Paramounts and they have made one of the largest differences almost akin to opening up a valve fully and allowing everything to come through.  Small changes are more apparent with the EML's.  Highly recommended do those who are on the fence or looking to upgrade their 2A3 tubes.

I'm not running a Bottlehead preamp and am unable to give you a good answer to your question if it was directed at me. 

Regards,

Aaron