Late to the party - looking for info on older Foreplay, Seduction and Afterglow

[mas]

Hi all, I just became a bottlehead this week. I purchased a used set of products estimated to be about ten years old: original Foreplay, Seduction and Afterglow.   They all have the C4S upgrade, and the Afterglow has some custom modifications.

After finding and fixing a bad solder joint in the Foreplay, everything is up and running, and sounding great! Wow, not much usable volume on the foreplay, though. And the bass on the Afterlow isn't that strong with my Klipsch Forte.

Anyways, I'm sure this has all been gone through, and the old archives have lots of information. I would like to get a copy of the manuals, and copies of the valve magazines, and wondered if these are still available. I'm sure I'll have some other questions after living with these for a bit, but will save those for another post after reviewing the info that is available.

[Grainger49]

You have experienced the infamous Foreplay Hair Trigger Syndrome.  It is well documented and extremely easy to fix.

Depending on how much of the FP volume control you use you insert a resistor to pad down the volume you do use.

The stock volume pots are 100k ohms.  If all sources are too loud you put the padding resistor between the selector switches and the volume pots where there is now a wire.  To cut the volume in half insert a 100k ohm resistor. 

If you want to pad the phono and CD inputs differently, my Seduction doesn't need padding, you put a resistor in series with the input you want to pad.  For instance, you could put 100k in series with the CD inputs.  That is, between the input RCA jack center lead and the selector switch.  You might want to pad the Seduction input a little, put a 33k ohm between the Seduction input RCA jack center lead and the selector switch. 

Do your Afterglows have upgraded iron?  If not the MagneQuest iron will improve the bass.  At the same time you will need to upgrade, increase the value of, your parafeed caps in them.

I  hope this helps some.

[Paul Birkeland]

The Afterglow came with TFA-204's IIRC, so iron shouldn't be an issue.  If the amps are 10+ years old, and have seen regular use, it might be a good idea to get the tubes checked out. The 12AU7's and 12AT7's are more than likely OK, but I would wonder about the 2A3's...  As both circuits are directly coupled, it is quite important to make sure the tubes are working properly.

[mas]

Per the previous owner, the TJ Mesh 300B 2.5V have about 200 hours. The driver tubes are 5965's with high hours.    Yea, maybe a fresh tube set all the way around would make sense. Experience has taught that it is good to have spares!

[Grainger49]

I should have added that I don't know the Afterglows.

[Air]

Hello Mas and welcome to the club. concerning the TJ Meshplate 300B 2.5V tubes. 200 hours on these tubes is just break-in mileage (think Honda Accord with 5K miles). A premium tube to be sure. -Chuck

[Paul Birkeland]

Per the previous owner, the TJ Mesh 300B 2.5V have about 200 hours. The driver tubes are 5965's with high hours.    Yea, maybe a fresh tube set all the way around would make sense. Experience has taught that it is good to have spares!

Hmm, I would indeed get a fresh set of 5965's and a cheapo pair of 12AU7's for the Foreplay.  Heck, a pair of Sovtek 2A3's probably wouldn't hurt anything either as a reference.  What I would do if I had your gear is:

1.  Get a NOS pair of 5965's, and a new pair of Sovtek 2A3's.  
2.  Run one amplifier with the tubes you have now, and measure the voltage across the cathode resistor on the 2A3 (it will be attached to the center of the hum pot under the amplifier).
3.  Replace the 5965 and repeat the voltage measurement.
4.  Replace the 2A3 (and using the new 5965) repeat the voltage measurement
5.  Go back to the old 5965 and use the Sovtek 2A3 and perform the measurement again

If you post those numbers here, we can give you some assessment of the condition of the tubes in your gear without a massive investment in new tubes.  

[Paul Joppa]

There were several slight variations on the Afterglow, and you say yours has been modified as well, so when you are ready to look into it we'll have a bunch of questions - things like is the driver paralleled (or even did it have the Tucker regulator board), which power transformer, which cathode resistor value, etc.

Because this was series feed (before Bottlehead got seriously into parallel feed) it has the TFA-204, and CB mentioned. That transformer still has the best midrange and highs of any I know, but bass is not its strongest suit. Depending on the operating conditions, it may be possible to improve it somewhat. Incidentally, using the 2.5v 300B you should get a very long life from the power tube.

[mas]

Thanks for all the responses. 

I've made two changes that have helped. Of course I made the two changes at the same time so I don't know which one helped the most.
I swapped out the foreplay tubes for some tubes I had on hand - unbranded made in Germany.  I also switched the 5965's from one amp to the other, having read only one half of the dual triode is used.  The bass impact has improved greatly. Less distortion too.

I have ordered some fresh JAN Philips 6922's  for the seduction, and some Sylvania 12au7's  for the Foreplay, and will also order the Sovtek 2A3's and 12v7's shortly.  I'll report back after they arrive. 

Are the installation manuals available for these units?

[Grainger49]

Easy to check.  Put the original tubes back in the FP.  Then swap the 5956s again.  But do these one at a time.

Seems to me when Bottlehead uses 1/2 of a dual triode they might wire the other amp to use the other half.  That way you get double mileage out of the tubes.  But I read that they had once used both halves in parallel.  That is cool!

If neither of these swaps brings back the weak bass, the tubes just needed reseating.

You should email, better yet call, the Queen at Bottlehead to check on the manuals.

[mas]

Thanks for all the replies.  I also heard from Eileen, and she is sending the manuals.

The sets are settling in nicely. They had been sitting in someone's basement, and I know the connections were dirty/corroded. I think most of the improvement has come from cleaning the connections and reseating all the tubes. I also replaced the sovtek 6922's with some Philips jan 6922 and the foreplay 12au7's with some baldwin sylvania 12au7's.   Some garbling type of distortion has completely disappeared, and bass impact is greatly improved. I've ordered the sovtek 2a3's and some fresh 12av7's.

Would it be ok to use Caig deoxit D5 in the tube sockets? I'm sure it's ok on the rca's but I'm not sure what the higher voltages will do. Actually, I used some Turomat TC-2 contact enhancer in the rca connections.

Honestly, the sound is unbelievably good, better than I can remember in my room.  I played an OJC reissue of Bags meets Wes! last night, and the "you are there" clarity of the guitar and vibes was exceptional.

[Grainger49]

Deoxit is fine. It is just messy.  The best way to apply it is using the brush bottle or the needle bottle.  That way there is a minimum of it getting where it is not needed.  After applying reseat the tubes several times to clean off any oxidation that is being loosened by the Deoxit.