Tightening up a 50w

[4styx]

Hi. I'm new here.I didn't build the amp.Everthing is standard lead specs with L/M PPI master.After 3:00 on vol 1 it gets really bloated(too much flubby bass).
I ordered a .0022 coupling cap.Is it worthwhile putting one on the V1a(low Vol) as well?It was also suggested to replace the cap on the presence pot with a .068.
I can't find one that is 400v though.The presence now has a .1uf 400v and doesn't have much of an effect.
Looking forward to some advice from the pros here. Thanks

[neikeel]

Hi. I'm new here.I didn't build the amp.Everthing is standard lead specs with L/M PPI master.After 3:00 on vol 1 it gets really bloated(too much flubby bass).
I ordered a .0022 coupling cap.Is it worthwhile putting one on the V1a(low Vol) as well?It was also suggested to replace the cap on the presence pot with a .68.
I can't find one that is 440v though.The presence now has a .1uf 400v and doesn't have much of an effect.

Need to have a quick peak at the amp innards, never quite know what someone has built as stock. Don't usually think of a proper lead spec 50watter as being flubby...............

Looking forward to some advice from the pros here. Thanks

Can't do that but I do have an idea about what makes a 50watter tick.

What are you after? Decent filter caps (50/50 cans throughout help). Choice of NFB is important, in fact lots of things, including speakers.

Show us what you've got tell us what you want and I am sure someone will be able to help

[4styx]

I was afraid someone was going to ask for pics.I never have much luck with that.Message says my pics are too big. Here's a link to them on facebook.

https://www.facebook.com/album.php?ai...8&l=50290db0f5 Even that does'n't seem to work.Worked for me on TGP though.???http://www.facebook.com/album.php?aid=1 ... 50290db0f5 OK This one works.

[Kramer]

Just go into paint if your using Windows Image -> Stretch Skew and then set a percentage of length and width you want to shrink it. Or, just get an ImageShack account and upload your pictures straight to the internet. It's free and gives you options to link pictures on other websites.

Good luck on your amp!

[syscokid]

One of the very few things that I do know is that the more you tame the volume by using PPIMV, the less effect the Presence Control will make.

[4styx]

I was checking out the Tranny comparison clips that Slystrat put up in his OT thread.The Weber,Heyboer and Mag inc clips all sounded similar to me.But with the MM clip I was hearing everything that I'm not liking about this amp.Big fat,somewhat indistinct,bottom end with a high treble spike on the other end.
I'm not looking forward to swapping out the OT,just yet anyways.Will lowering the B+ subdue this affect at all?
Syscokid, good call on the presence cap.
I'll work on those pics as soon as I have time.Thanks all.

[4styx]

I decided to try some new tubes first(EL-34M GT).Both tubes light up,but am getting no current reading on V4.B+ is 450v on V5,444v on V4.Both tubes light up.
I think I might be in over my head on this one.

[eddie25]

Is it making any noise with the new tubes in? Are you using the 1 ohm resistor to get a current reading?

[4styx]

Yes it hums pretty bad.I'm using a new Bias-rite(dual socket).I'm not a %100 sure the meter is working properly,but the readings follow the socket(V4).At V4 I'm getting a -.018 reading.
450v is pretty high for this curcuit I think.I had to max the bias pot to get 38mv.
I haven't plugged into it yet to see if works as before,kind of leary to turn it on at all.

[HTH]

what sort of volumes are you using the amp at? - if you're running the amp quite low, the PPI-MV pretty much disables the NFB in the amp, hence the amp sounds dirtier, but looser too.

I don't see the attraction of PPI-MVs myself, I think they change the amp's tone drastically. Just put a pre-PI MV like Marshall used on the 2203/2204 amps and be done with it. This always sounds great in the amp's I've used them in (lots).

Alternatively, use the Jose master without the diodes - works great with plexis and keeps the amp sounding fat even at low volume and gain.

[Kapo_Polenton]

My friend, head on over to this post where I was asking how I could tighten/brighten/and crunch up my 50 watt 1987x. My amp is tight enough I'd say.. http://forum.metroamp.com/viewtopic.php?f=16&t=29466" onclick="window.open(this.href);return false;. Mine is tight enough now.. i am just dealing with a bit of the fizzies on the B and E strings but it is getting there.

Couple things: Use this layout for reference: http://forum.metroamp.com/viewtopic.php?f=26&t=15719" onclick="window.open(this.href);return false;

1. V1A plate cap -- .0022
2. Leave the phase inverter coupling caps the way they are .022
3. NFR - 47k. Keeps it tight.
4. I like 500 pf bright cap. Play the amp on 7-8. At ten it is out of the circuit and it fattens up. This one makes a hige diff.
5. V2A bypass cap. .068 will be tighter and more mids. I am rockin out with a 330 right now as it provides a bit more even gain and i feel a bit more girth.
6. Tone stack 56/250.

7* presence cap I have not tried but have heard it does what you describe and that Lynch had a preference for .068.

Anyway, hope it helps.

PS- My plate voltage is roughly the same as yours and that is where I bias my tubes too.

[Kapo_Polenton]

Alternatively, use the Jose master without the diodes - works great with plexis and keeps the amp sounding fat even at low volume and gain.

HTH I agree with you on the PPIMV. I kind of prefer the regular pre PI 2204 type volumes. I always felt they kept the tone tight. Where can I find out more about this Jose master without diodes? Is there a layout or schem? Does it add a tad of gain anywhere?

[Coot Boy]

Alternatively, use the Jose master without the diodes - works great with plexis and keeps the amp sounding fat even at low volume and gain.

Where can I find out more about this Jose master without diodes? Is there a layout or schem? Does it add a tad of gain anywhere?

Haven't tried it myself but here it be.

[Kapo_Polenton]

I suppose HTH is referring to doing this with no diodes or zeners. Just the POT, cap , and resistor.

[Coot Boy]

Oh don't mention it mate.