12ay7 PI?

[bhsbhswarp]

for giggles I put a 12ay7 in the phase inverter slot.Wow,really liked the crisp tones I was getting on my DC 3.Does using a 12ay7 in V6 hurt the amp at all??Did some checking and seems to be a better choice then a AT7.12ay7 specs pretty close to a 12ax7 other then the gain factor of course.

 

[bhsbhswarp]

I think I've answered my own question here.The 12ay7 is like installing a 12at7.It's looses just a little output,but retains the highs and bass better then the non-musical 12at7.It also gives the amp a less gritty/fizzy distortion.All the techs I've spoken with say it makes a fine driver tube in place of a 12ax7,it just doesn't breakup as raspy as a 12ax7.It seems to smooth it out just a little more musical kind of clip when driven hard. :mrgreen:

 

[BobR]

I would try both(12AT7 and 12AY7). See which works best. Of all the places to try the "less than musical" 12AT7 the PI is a good one.Bob

 

[bhsbhswarp]

Iwas running a 12at7 in the PI and liked it fine.The 12ay7 is just better in tone for me.Seems to have a better range of treble and bass.The amp still has plenty of volume on tap.

 

[BobR]

Iwas running a 12at7 in the PI and liked it fine.The 12ay7 is just better in tone for me.Seems to have a better range of treble and bass.The amp still has plenty of volume on tap.

Could be the balance of the triodes or the other parameters of the tube that react differently when subbed for a position optimised for a 12AX7. Could be the tube type itself-or both. I havent experimented with the DC-3's PI -yet. I do have a full compliment of old stock 12AX7's in it though. Raytheons,RCA,Sylvania at the moment.

Ive got so many old stock tubes its almost a challenge to figure out what to try next. Often I'll try 4-5 of each brand,let alone tube type in a position. Out of the 20-30 different brands of old stock tubes that becomes a luxury problem ,no doubt, but daunting! I'll have to pull out my 12AT7's and 12AY7's and do some tube rolling in the PI. : > ) Bob

 

[bhsbhswarp]

Iwas running a 12at7 in the PI and liked it fine.The 12ay7 is just better in tone for me.Seems to have a better range of treble and bass.The amp still has plenty of volume on tap.

Could be the balance of the triodes or the other parameters of the tube that react differently when subbed for a position optimised for a 12AX7. Could be the tube type itself-or both. I havent experimented with the DC-3's PI -yet. I do have a full compliment of old stock 12AX7's in it though. Raytheons,RCA,Sylvania at the moment.

Ive got so many old stock tubes its almost a challenge to figure out what to try next. Often I'll try 4-5 of each brand,let alone tube type in a position. Out of the 20-30 different brands of old stock tubes that becomes a luxury problem ,no doubt, but daunting! I'll have to pull out my 12AT7's and 12AY7's and do some tube rolling in the PI. : > ) Bob

I'll be looking forward to your thoughts Bob.

 

[scottcrud]

I will have to try that, the 12AT7 in the pi of my Boogies has long been a secret weapon of mine. I tried a 12AU7 and did not like it at all. Guess I need to order a 12AY7.

 

[BobR]

Iwas running a 12at7 in the PI and liked it fine.The 12ay7 is just better in tone for me.Seems to have a better range of treble and bass.The amp still has plenty of volume on tap.

Could be the balance of the triodes or the other parameters of the tube that react differently when subbed for a position optimised for a 12AX7. Could be the tube type itself-or both. I havent experimented with the DC-3's PI -yet. I do have a full compliment of old stock 12AX7's in it though. Raytheons,RCA,Sylvania at the moment.

Ive got so many old stock tubes its almost a challenge to figure out what to try next. Often I'll try 4-5 of each brand,let alone tube type in a position. Out of the 20-30 different brands of old stock tubes that becomes a luxury problem ,no doubt, but daunting! I'll have to pull out my 12AT7's and 12AY7's and do some tube rolling in the PI. : > ) Bob

I'll be looking forward to your thoughts Bob.

So I tried a Sylvania black plate JAN 12AT7 in my DC-3 today. It seems clearer -less midrangey. Not sure about this yet as I only tried one-more testing is needed. Bob

 

[bhsbhswarp]

after further noodle's,the lower gain tubes work out real well for home use,but the 12ax7 is were it's at when it comes to the full band thing.IMO of course.I think for recording it would also be better to have the lower gain for less noise.I've also realized that different 12ax's make big differences too.

 

[BobR]

after further noodle's,the lower gain tubes work out real well for home use,but the 12ax7 is were it's at when it comes to the full band thing.IMO of course.I think for recording it would also be better to have the lower gain for less noise.I've also realized that different 12ax's make big differences too.

Yeah Iva amassed about 1000 old stock 12AX7's,12At7's,5751's,etc. Kind of an addiction really. lol! Im 1/2 cork-sniffer. I use old stock 12AX7's and new production power tubes. On a side note-I just bought a lot of 40 Sovtek EL84M's off ebay for 92$. I'll see how good a deal that was when they get here. : > ) Bob

 

[gibsonboogie]

I bought a DC3 (orig) a few months ago and I started using an EH 12AY7 in the PI about a month ago. It sounds excellent. I was not too crazy about that tube in other positions or in other amps, but it seems to complement the other tubes I have in that DC (a mix of MB, JJ and Mullard 12ax7). It reduced my output volume by a very slight, almost unnoticeable amount, but can still drive the EL84 output tubes past the breakup point.

It's worth a shot if someone is looking for a different, slightly less driven sound. I would not consider this an effective volume mod. On a separate note, and I am considering starting a new thread for this, but I replaced the EL84's with JJ EL844's. This did produce a noticeable drop in volume, but not a tremendous drop.