Amp modders... How do I smooth out the 1-wire mod?

[Vrad]

I've been looking into how to make it less grainy/buzz. Any ideas?

Olaf? Steve(sah5150)?
Here are some gut pics

 

[stratotone]

I just started messing with my plexi clone and the 1-wire mod... have you tried removing some of the cathode bypass caps on the first stages? That would cut gain and buzz/fuzz for sure.

Pete

 

[jerrydyer]

post the signal chain. Theres a million ways to run that one.

 

[Vrad]

I just started messing with my plexi clone and the 1-wire mod... have you tried removing some of the cathode bypass caps on the first stages? That would cut gain and buzz/fuzz for sure.

Pete

No they're still stock mustard caps. I've seen people change the values on them.

 

[Vrad]

post the signal chain. Theres a million ways to run that one.

Uhmm... It's the one wire mod from SDM's site. I used shielded wiring and no push/pull pot.
It's here: http://home.comcast.net/~jbjdav26/1Wiremod.zip
At the moment its
V1A Cathode 2.7k/.68uf
V1B Cathode 2.7k/.68uf
V2A Cathode 810/.68uf

Oh yeah the bypass caps are 2n2 and .022uf

NFB 47k on the 8 ohm tap.

 

[jerrydyer]

drop the 470k to a 68 k and remove one of the 68k. pref on the second gain stage.

 

[Vrad]

drop the 470k to a 68 k and remove one of the 68k. pref on the second gain stage.

Are you talking about the other mixer resistor on the board?

 

[jerrydyer]

the 470 k between the first two gain stages

 

[jerrydyer]

ooops I meant the .68 cap on second gain stage. but I also chnge the 470 k between them to a the 68k . But I also like .1uf instead of the .68 and also a .47 instead of the other . 68

 

[Vrad]

ooops I meant the .68 cap on second gain stage. but I also chnge the 470 k between them to a the 68k . But I also like .1uf instead of the .68 and also a .47 instead of the other . 68

You mean a .1uf on the V1A Cathode and .47uf on the V1B cathode?

 

[Vrad]

Hey Jerry,

I tried what I think you were saying.
V1A 2.7k/.22uf (didn't have a .1uf)
V1B 2.7k/.47uf

I left the 810/.68uf on the V2A for now and didn't touch the 470k resistors yet.

It sounds alot better. Less splattery and messy. Sounds really good with my OD808 as a boost.

 

[Chubtone]

Sounds really good with my OD808 as a boost.

Vlad,
Didn't it sound really good with your OD808 as a boost before you started modding it?

 

[ericsabbath]

Hey Jerry,

I tried what I think you were saying.
V1A 2.7k/.22uf (didn't have a .1uf)
V1B 2.7k/.47uf

I left the 810/.68uf on the V2A for now and didn't touch the 470k resistors yet.

It sounds alot better. Less splattery and messy. Sounds really good with my OD808 as a boost.

22u, 2.2u or .22u (220n)?

I'd go with 1u and then you can leak some treble to the ground after the first stage with a small cap (between 100p and 560p)
it's a very common trick to keep amps smooth and middy
you'll find this in a lot of famous amps
you can also use a higher value and then install a pot or trimpot to fine tune the effectiveness of the cap (like a bite/edge/bright control)
a small high voltage cap linking the plate pins of the phase inverter is useful too (regular value is 47pf, but you can only notice some difference above 120p)

 

[Vrad]

Sounds really good with my OD808 as a boost.

Vlad,
Didn't it sound really good with your OD808 as a boost before you started modding it?

Yeah that amp always sounded good... LOL!
I'm not touching stuff that hasn't already been touched before I got the amp.

 

[Vrad]

Hey Jerry,

I tried what I think you were saying.
V1A 2.7k/.22uf (didn't have a .1uf)
V1B 2.7k/.47uf

I left the 810/.68uf on the V2A for now and didn't touch the 470k resistors yet.

It sounds alot better. Less splattery and messy. Sounds really good with my OD808 as a boost.

22u, 2.2u or .22u (220n)?

I'd go with 1u and then you can leak some treble to the ground after the first stage with a small cap (between 100p and 560p)
it's a very common trick to keep amps smooth and middy
you'll find this in a lot of famous amps
a small high voltage cap linking the plate pins of the phase inverter is useful too (regular value is 47pf, but you can only notice some difference above 120p)

You mean .1uf?

 

[Anonymous]

Hey Jerry,

I tried what I think you were saying.
V1A 2.7k/.22uf (didn't have a .1uf)
V1B 2.7k/.47uf

I left the 810/.68uf on the V2A for now and didn't touch the 470k resistors yet.

It sounds alot better. Less splattery and messy. Sounds really good with my OD808 as a boost.

22u, 2.2u or .22u (220n)?

I'd go with 1u and then you can leak some treble to the ground after the first stage with a small cap (between 100p and 560p)
it's a very common trick to keep amps smooth and middy
you'll find this in a lot of famous amps
a small high voltage cap linking the plate pins of the phase inverter is useful too (regular value is 47pf, but you can only notice some difference above 120p)

You mean .1uf?

He means 1uF and I believe that is what Jerry meant as well...

Steve

 

[ericsabbath]

You mean .1uf?

1u
.1u is 100n and that would be very spikey
are you sure you have .22u instead of 22u?

 

[Vrad]

Hey Jerry,

I tried what I think you were saying.
V1A 2.7k/.22uf (didn't have a .1uf)
V1B 2.7k/.47uf

I left the 810/.68uf on the V2A for now and didn't touch the 470k resistors yet.

It sounds alot better. Less splattery and messy. Sounds really good with my OD808 as a boost.

22u, 2.2u or .22u (220n)?

I'd go with 1u and then you can leak some treble to the ground after the first stage with a small cap (between 100p and 560p)
it's a very common trick to keep amps smooth and middy
you'll find this in a lot of famous amps
a small high voltage cap linking the plate pins of the phase inverter is useful too (regular value is 47pf, but you can only notice some difference above 120p)

You mean .1uf?

He means 1uF and I believe that is what Jerry meant as well...

Steve

So on the V1A, you're saying 2.7k/1uf?

 

[Vrad]

You mean .1uf?

1u
.1u is 100n and that would be very spikey
are you sure you have .22u instead of 22u?

That's what I had.
http://metroamp.com/store/index.php?mai ... cts_id=157

 

[Anonymous]

Hey Jerry,

I tried what I think you were saying.
V1A 2.7k/.22uf (didn't have a .1uf)
V1B 2.7k/.47uf

I left the 810/.68uf on the V2A for now and didn't touch the 470k resistors yet.

It sounds alot better. Less splattery and messy. Sounds really good with my OD808 as a boost.

22u, 2.2u or .22u (220n)?

I'd go with 1u and then you can leak some treble to the ground after the first stage with a small cap (between 100p and 560p)
it's a very common trick to keep amps smooth and middy
you'll find this in a lot of famous amps
a small high voltage cap linking the plate pins of the phase inverter is useful too (regular value is 47pf, but you can only notice some difference above 120p)

You mean .1uf?

He means 1uF and I believe that is what Jerry meant as well...

Steve

So on the V1A, you're saying 2.7k/1uf?

Yes, correct. You could also try a 1.5K/4.7uF V1A and up the grid resistor to 150K

Steve