Soldano SLO Gain Vs. Hot Rod Gain

Mesa\Kramer

New member
For those who have owned or have had some playing time with both.
Do both have similar gain structure?

The reason I ask is that I recently got a Jet City 50 (Which is a Soldano designed HR 50 made over seas).

The amount of gain on tap from the Jet City is considerably more than my SLO.

The Normal channel alone on the JC with the gain on 3-4 is as much as the normal channel on my SLO set at max.

Maybe there is something wrong with my SLO or the HR series is designed with more gain?
 

maynardo

New member
Chinesse preamp tubes are gainier than most, try the ones from the JC in the SLO.

Funny thing is that in fact the JC preamp circuit has slightly less gain than the Soldano HR (the voltage divider after the second stage is different). With that said, the gain pot in the JCs and HRs are 1Megs and that does give you more gain than the 500k of the SLO, but difference should not be that big really
 

Racerxrated

Well-known member
To me the SLO has the same amount of gain as my old HR100. I've had 2 SLOs..one from 2002 and one from 2012 and both seemed identical...I ran both the SLO and HR the same though. Gain at 6-7 and boost mids with an eq pedal..
 

lespaul6

Well-known member
Ive had a few SLO's as well... when I had the hot rod 100 and 50 I thought the clean channel got dirty quicker and the dirty channel got dirty later than the SLO.
 

Jack Luminous

Active member
Maybe something's wrong with your SLO. Mine has an ungodly amount of gain on the lead channel. I cannot fathom anyone needing more. I play death-metal with gain at 1:30 approximately (with high-output humbuck). It turns to total unusable mayhem at about 3:00...
 

sahlomonic

Well-known member
The gain pots are a different value on your Jet City than the SLO (Hot Rod is different as well). I modded my JCA50H and 100H to have the same component values as an SLO. Made a big difference, especially in how usable the gain pots became.
 

bwgintegra

Well-known member
maynardo":1fivtt0s said:
Chinesse preamp tubes are gainier than most, try the ones from the JC in the SLO.

Funny thing is that in fact the JC preamp circuit has slightly less gain than the Soldano HR (the voltage divider after the second stage is different). With that said, the gain pot in the JCs and HRs are 1Megs and that does give you more gain than the 500k of the SLO, but difference should not be that big really

I did some mods to my JC50H, what resistor is different in the voltage divider after the second stage. From the schematics I have of both I didn't see any differences.
 

bwgintegra

Well-known member
Here is what mine looks like after the mods, the depth mod is a must. This thing really sounds good, $350 for the amp and $50 in parts.

The bottom picture are parts that I removed and replaced

5623FF12-B305-42C0-9416-336316D19823.jpg

21C32E39-6C2C-4313-8C99-EBCC318C9331.jpg

5623FF12-B305-42C0-9416-336316D19823.jpg

B8D8A6DA-330A-4F59-9617-7C2A0123DE09.jpg
 

FourT6and2

Well-known member
midnightlaundry":1x96f21i said:
Are those 716P caps?

Looks like it. Soldano has never used 716p caps in the SLO though. They've historically been the Philips MKT variety, but now Vishay MKT368 series, since Philips no longer makes the MKT.
 

maynardo

New member
bwgintegra":2hp1ej01 said:
maynardo":2hp1ej01 said:
Chinesse preamp tubes are gainier than most, try the ones from the JC in the SLO.

Funny thing is that in fact the JC preamp circuit has slightly less gain than the Soldano HR (the voltage divider after the second stage is different). With that said, the gain pot in the JCs and HRs are 1Megs and that does give you more gain than the 500k of the SLO, but difference should not be that big really

I did some mods to my JC50H, what resistor is different in the voltage divider after the second stage. From the schematics I have of both I didn't see any differences.

The schematics are wrong, the voltage divider has load of 470k, not 1M. Unless they chanched at some point, I mean they've been making these amps for like 5 years now, I guess at some point they could've gone to the original.
 

FourT6and2

Well-known member
bwgintegra":1yyq326n said:
The entire preamp section is Vishay MKT368's.

Oh weird. Vishay MKT caps typically have the writing on the top, not the side. I think that's why it looks like 716.

DSCF3891.jpg
 

bwgintegra

Well-known member
FourT6and2":2clwqfun said:
bwgintegra":2clwqfun said:
The entire preamp section is Vishay MKT368's.

Oh weird. Vishay MKT caps typically have the writing on the top, not the side. I think that's why it looks like 716.

DSCF3891.jpg

If you look at the preamp section the writing in on the top. It's not as dark as the ones you pictured but if you closely you can see it.
 

midnightlaundry

Well-known member
Those are polyester. Cool then! I redid the tones caps on my JCA5012C with 228P polyesters. It sounds good.

My Deliverance has 228P's. So it's in good company.
 

FourT6and2

Well-known member
bwgintegra":30qyglu2 said:
If you look at the preamp section the writing in on the top. It's not as dark as the ones you pictured but if you closely you can see it.

How did the amp's tone change with the cap change? I built my SLO clone with 716p caps. That was before I realized I should have gone with the MKTs and I'm curious to hear if the difference is that noticeable.
 

bwgintegra

Well-known member
FourT6and2":3mvrfb6a said:
bwgintegra":3mvrfb6a said:
If you look at the preamp section the writing in on the top. It's not as dark as the ones you pictured but if you closely you can see it.

How did the amp's tone change with the cap change? I built my SLO clone with 716p caps. That was before I realized I should have gone with the MKTs and I'm curious to hear if the difference is that noticeable.

After changes the amp sounded a lot smoother, not such a harsh top end. The biggest difference I noticed was the feel of the amp while playing, the response was there and could feel the difference under the fingers. The depth control also contributed to allowing to add a great punchy bottom end that was lacking in the stock amp.

To the original post, with the gain at noon it's more than enough. I have never owned a real SLO but did have a SLO clone and with the mods I did I set them up pretty much the same.

Re-guarding the mods I did, I was never trying to copy the exact SLO circuit or components. I was basically trying to improve the overall tone and sound of the JCA50. Below are a list of the components I changed, everything was ordered from Mouser.
E291AE8A-3907-4A21-ABBB-AF93DC69F8B5.jpg
 
Top