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No more Procrastination! (An interesting small valve head story)

Bridgehouse

By Bridgehouse,
in Amps and Cabs

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Twincam Proficient

Twincam

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Posted

Replaced the v1 12ax7 in my pf20t, with a Tung sol 12ax7 reissue, after a few hours, seems to be an improvement in clarity and smoother breakup than the Chinese ruby it replaced. 

My eq is now flat, before I had to slightly cut the bass and boast mids and treble. Gain is about the same, disappointingly! I think I might buy a golden lion or sovtek 12ax7lps for v1 as they have a bit more gain apparently and move the tung sol to v2. 

Now I don't know if tube break in is real but I'm pretty sure after about 4 hours plus the tung sol improved a lot from first use. At first it seemed a bit wooly, it's now opened up. 

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JapanAxe Grand Master

JapanAxe

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19 minutes ago, Twincam said:

Replaced the v1 12ax7 in my pf20t, with a Tung sol 12ax7 reissue, after a few hours, seems to be an improvement in clarity and smoother breakup than the Chinese ruby it replaced. 

My eq is now flat, before I had to slightly cut the bass and boast mids and treble. Gain is about the same, disappointingly! I think I might buy a golden lion or sovtek 12ax7lps for v1 as they have a bit more gain apparently and move the tung sol to v2. 

Now I don't know if tube break in is real but I'm pretty sure after about 4 hours plus the tung sol improved a lot from first use. At first it seemed a bit wooly, it's now opened up. 

Ooh! I bought a Tung Sol 12AX7 recently, got to try that :). There's enough gain there for me as it is, the Gain control mainly changes the character from smooth to furry!

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Misowaki Enthusiast

Misowaki

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On 29/10/2018 at 19:59, JapanAxe said:

Took delivery of the PF-50T and connected it to my Super Twin, then plugged in my '73 P and played along with a classic soul compilation.

Oh. My. God.

Punchy, fat, touch-responsive sound. Smooth and effective tone controls, including a Treble control that actually has a useful effect with flat-wound strings. The Gain knob should actually be labelled 'Fur', as that's what it seems to control (in the best possible way).

This amp is all that I hoped it would be - and no hum, I'm pleased to say.

Here's the rig, and the settings I ended up with:

nOPHF9r.jpg

VsCdS7O.jpg

You turn the bass down?!  What kind of maverick renegade are you?!  

 

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afterimage Community Regular

afterimage

Posted
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On 31/10/2018 at 20:57, Twincam said:

Replaced the v1 12ax7 in my pf20t, with a Tung sol 12ax7 reissue, after a few hours, seems to be an improvement in clarity and smoother breakup than the Chinese ruby it replaced. 

My eq is now flat, before I had to slightly cut the bass and boast mids and treble. Gain is about the same, disappointingly! I think I might buy a golden lion or sovtek 12ax7lps for v1 as they have a bit more gain apparently and move the tung sol to v2. 

Now I don't know if tube break in is real but I'm pretty sure after about 4 hours plus the tung sol improved a lot from first use. At first it seemed a bit wooly, it's now opened up. 

It will do after a few hours use also use the stand by to warm up 

 

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JapanAxe Grand Master

JapanAxe

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I took the precaution of testing the Ruby Tubes that came installed, using my Orange Valve Tester.

  • V1 (12AX7) tested 'worn' so I replaced it with a known good Tung Sol.
  • V2 (12AX7) tested 'good'.
  • V3 (12AU7) tested 'bad' - one of the triodes only scored 1 on Orange's arbitrary scale of 1-15, so I replaced it with a JJ that had a slightly better score. Fortunately the driver arrangement means the triodes do not need to be matched.
  • V4 & V5 (6L6) both tested 'good' with closely matched ratings.

I don't want to be swapping valves too often - the screws are fiddly to replace (and easy to lose), and it takes a fair amount of force to remove the pre-amp valves!

I have a country gig tomorrow night, not a loud band, so an ideal opportunity to see how the amp fares against a drummer and two guitarists. (In case you're interested, it's the Crow Valley Band, and the venue is Middleton Cheney Social Club, Astrop Road, Middleton Cheney, Banbury OX17 2PG - it will cost you £6-£7 to get in.)

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afterimage Community Regular

afterimage

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The PF-50T's tubes are all from Ruby Tubes. There's a a pair of 6L6GC-MSTR power tubes and three nine-pin preamp tubes - two 12AX7s, with one for preamp and gain in V1, and the other handling EQ and amp drive in V2, and a 12AU7 in V3 that functions as a phase splitter for the power amp section. The PF-20T uses a similar all-tube setup, but with two 12AX7's and a pair of 6V6 power amp tubes. All the tube sockets are ceramic, and tube retainers are provided for the power tubes, with shields for the preamp bottles. 

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JapanAxe Grand Master

JapanAxe

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26 minutes ago, afterimage said:

The PF-50T's tubes are all from Ruby Tubes. There's a a pair of 6L6GC-MSTR power tubes and three nine-pin preamp tubes - two 12AX7s, with one for preamp and gain in V1, and the other handling EQ and amp drive in V2, and a 12AU7 in V3 that functions as a phase splitter for the power amp section. The PF-20T uses a similar all-tube setup, but with two 12AX7's and a pair of 6V6 power amp tubes. All the tube sockets are ceramic, and tube retainers are provided for the power tubes, with shields for the preamp bottles. 

Correct. I have found that ceramic valve sockets can be very tight to get the valves in and out of!

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pbasspecial Mentor

pbasspecial

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Posted

Yes. Maybe. YMMV, etc

The past is the past and there is only the now.  It all depends on what you want it to do.  I love the look and feel of classic cars (especially a Mercedes 280SE) but I wouldn't have one as my everyday car.  This will give you a close approximation of the look and sound of the old classic amps but with modern reliability.  Plus at just over £400 new with warranty you can't go wrong.  However, If you want to spend £2,000 on a 50 year old amp that will get easily damaged in transit and you will struggle to get parts for, knock yourself out. I would love an old B15 but it would never leave the house.  Which would be a crime I'm not willing to commit.

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Beer of the Bass Mentor

Beer of the Bass

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38 minutes ago, Pea Turgh said:

I’d just been reading about B15’s & B12’s, then thought of this thread.

Sorry if this has already been covered, but wattage aside, are these new valve heads recreations, reimaginations or just looky likeys  of those old 60’s beasts?

It's probably best to think of them as modern small valve heads, with elements of various older Ampegs informing the design.  The midrange EQ circuit is closer to some of their larger amps, and the power amps are designed quite differently to the B15n.  So while they sound recognisably "Ampeg", they're not recreating any specific vintage model. 

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Pea Turgh Veteran

Pea Turgh

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Just out of interest really - I was reading opinions on how the old ones were the best sounding bass amps ever made, and wondered how close the new ones came to that accolade.

I’m not thinking of buying a new one, and I definitely couldn’t justify owning/maintaining an old one.  I’ll carry on with my little pf350 for the foreseeable as I’m only doing pub gigs and weddings 😁

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JapanAxe Grand Master

JapanAxe

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Posted
5 hours ago, Pea Turgh said:

Just out of interest really - I was reading opinions on how the old ones were the best sounding bass amps ever made, and wondered how close the new ones came to that accolade.

I’m not thinking of buying a new one, and I definitely couldn’t justify owning/maintaining an old one.  I’ll carry on with my little pf350 for the foreseeable as I’m only doing pub gigs and weddings 😁

 

@disssa has reviewed both the PF-50T and the PF-20T on his excellent website. You will need Google translate unless you have very good German.

Spoiler - he reckons the PF-20T sounds more like a B15 than the other one.

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Beedster Grand Master

Beedster

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13 hours ago, JapanAxe said:

@disssa has reviewed both the PF-50T and the PF-20T on his excellent website. You will need Google translate unless you have very good German.

Spoiler - he reckons the PF-20T sounds more like a B15 than the other one.

Damn, wish I hadn't read that, now I want a PF-20T as well :) Having said that, given the variability between tubes, could the differences in the tests be down to the individual units as much as between models? It's also not unusual for two heads that sound very different through one particular cab to sound far more similar when both played through another or vice versa. OK, I'm simply trying to explain to myself why I don't need a PF-20T folks, so help me out :)

Re the tone generally, whilst I'm no expert, having previously owned a beautiful B-15, and given I've been looking for that same tone in something less expensive, I'd certainly say the PF-50T is closer than any other amp I've owned. It makes me smile from the first note, and the only other amp that did that was the B-15. 

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