Heh, SLO/5150/5150-III comparo

[Lake Placid Blues]

Re: Heh, SLO/5150/5150-III comparo

but not the right transformers. The deYoung transformers are really key to that SLO vibe.

I think that is a key point. If one examines the schematics of the SLO and most other high gain amps based on the SLO they are essentially Marshall 2203 JCM800 pre-amps with an extra preamp tube added, adding two more gain stages. The Rectifiers are like the SLO in that way as well. (Mesa Mks and Bogner XTCs are are very different, being based on Black Face Fender preamp design.) So what makes a SLO different?

It may be in large part the transformers and power supply. The SLO power supply, transformers, and power amp design details and those of the Rectifiers and others are obviously very different. SLOs do appear different from most in preamp function, if you do the calculations, in that they do not over do it at any one one point along gain chain in the pre-amp. It's the accumulated gain of the whole chain, not just squashing v1B or V2 extra hard.

[dystrust]

Re: Heh, SLO/5150/5150-III comparo

I think that is a key point. If one examines the schematics of the SLO and most other high gain amps based on the SLO they are essentially Marshall 2203 JCM800 pre-amps with an extra preamp tube added, adding two more gain stages. The Rectifiers are like the SLO in that way as well. (Mesa Mks and Bogner XTCs are are very different, being based on Black Face Fender preamp design.) So what makes a SLO different?

It may be in large part the transformers and power supply. The SLO power supply, transformers, and power amp design details and those of the Rectifiers and others are obviously very different. SLOs do appear different from most in preamp function, if you do the calculations, in that they do not over do it at any one one point along gain chain in the pre-amp. It's the accumulated gain of the whole chain, not just squashing v1B or V2 extra hard.

The point about accumulated gain is right-on. The Soldano preamp gradually clips several stages instead of one or two which is why it has so much gain yet retains clarity. Of the other similar amps I thought the Recto series came closest to this tone/vibe, though the power amp response is pretty different. If the Soldano has a depth knob, you can tune it to sound more Recto-ish, but you can't really go the other way. Gain/clarity is where the 5150 series loses most in comparison IMO. They have far more gain and compression than necessary, and suffer from very poor clarity at least when compared to a Soldano.

I'm kind of curious about the origins of your JCM800 preamp comparison as I'd always heard that the SLO was derived from a Blackface Bassman.

[Lake Placid Blues]

Re: Heh, SLO/5150/5150-III comparo

I'm kind of curious about the origins of your JCM800 preamp comparison as I'd always heard that the SLO was derived from a Blackface Bassman.

Unless the schematics I have are way wrong it is the case. Just remove the extra tube and the clean channel by pass, and its the JCM800 (2203/2204) or very close to it. The tone stack and its location in the circuit are also very similar. The tone Stack on a BF is early in the signal path. The Bogner XTC shows a strong Black Face influence.

[GilmourD]

Re: Heh, SLO/5150/5150-III comparo

The point about accumulated gain is right-on. The Soldano preamp gradually clips several stages instead of one or two which is why it has so much gain yet retains clarity. Of the other similar amps I thought the Recto series came closest to this tone/vibe, though the power amp response is pretty different. If the Soldano has a depth knob, you can tune it to sound more Recto-ish, but you can't really go the other way. Gain/clarity is where the 5150 series loses most in comparison IMO. They have far more gain and compression than necessary, and suffer from very poor clarity at least when compared to a Soldano.

I'm kind of curious about the origins of your JCM800 preamp comparison as I'd always heard that the SLO was derived from a Blackface Bassman.

Unless the schematics I have are way wrong it is the case. Just remove the extra tube and the clean channel by pass, and its the JCM800 (2203/2204) or very close to it. The tone stack and its location in the circuit are also very similar. The tone Stack on a BF is early in the signal path. The Bogner XTC shows a strong Black Face influence.

If it has a cathode follower then it would be based on a Marshall which was based on a '59 Tweed Bassman.

[Lake Placid Blues]

Re: Heh, SLO/5150/5150-III comparo

If it has a cathode follower then it would be based on a Marshall which was based on a '59 Tweed Bassman.

Indeed it does.

[SirJackdeFuzz]

Re: Heh, SLO/5150/5150-III comparo

Is there any GOOD You Tube clips of a SLO ?

I just want to hear this gain with clarity thing.

Thanks

[Lake Placid Blues]

Re: Heh, SLO/5150/5150-III comparo

Is there any GOOD You Tube clips of a SLO ?

I just want to hear this gain with clarity thing.

Thanks

Here's one of my favorites:

https://www.youtube.com/watch?v=G1jpQu6qR1E