Jeff Rowland Model 1 info

Hi everybody,

does anybody know if there's any (electrical) difference between the first and second series of the Jeff Rowland Model 1? In general, is there a difference between the black face units and the silver face ones? Thanks.

The later Generation has more watts, when I remember right 90W compared to 75W.

There is no difference between black and silver faceplates, it was only a option for personal taste.

But both are switchable to Mono, then they are excellent,
so buy 2 of them, when you want to go that route.
Wow, I didn't know there were two series. Is there any way to tell which version I have?

It's a long story how the amp came to me, but I basically didn't know much about it beforehand. Actually, I still don't, so any info you may have that isn't on the JRDG website would be appreciated. The reviews I read were all favorable, but none of them tested the amp out in bridged mode. One did make mention of a claim that unlike most amps, there is little or no sonic detriment involved when bridging this particular amp. Any truth to this?

Thanks in advance.
Just a quick addendum. I do remember an email exchange with Rich Maez (sorry if I mispelled his name) where he mentioned that the first series hummed audibly if you used the single ended inputs without shorting the balanced ones. Since I have not experienced this humming, is it safe to a assume that my amp is from the latter series? old post but no follow ups...I'm considering a Model 1 if anyone is still 'listening'...
I just bought a model 1 on AudioGoN and will report here as to how it works out. My plan is to eventually get a second one and run the pair bridged.
Early on in my listening to the Rowland Model One - but WOW! Air and detail to spare and smoother and much better bass on my speakers than my proceed amp 3 (not bad either though). Using a heavily modified Kenwood Kt-7500 tuner as my main source (see This is the best component in my system and plays very well via the Rowland.
Personnaly I had two differents Jeff Rowland Model 1 amp before. I'm not absolutly sure but there could be 3 or 4 differents versions of this amp.

The first one is the one shown on the original advert on Jeff Rowland's website (the black and white picture). You can recognize it because it has only 2 small black caps between the 2 big ones. I've never seen this version in second hand and maybe Jeff never sold it like this (it could be a prototype version).

The second version (also the first Model 1 I've bought) was a little bit different than the first version because here you could find 3 small black caps between the 2 big ones.
This version was running really hot, you could not put your hand on it more that 5 seconds before you get burned. Most of V2 can't be turned to mono (even if the switch is there). About the sound... it was just pure even (no joke), an extremly warm and full sounding amp. I sold it and it was a mistake. This amp can be found with a serial before 1300 (something like this).

The third version of the Model 1 is just a different amp (serial over 1300). You can recognize it because it has 2 small grey Philps caps between the 2 big ones. It is more powerful than V2 and it really turns off when you turn it off (sound just cut, on the V2 it degrease slowly and stay on at a really low level all the time). But the V3 is just the shadow of the V2 for me. The sound is much much more common... nothing really special there. The amp doesn't run hot anymore, you can put your hand on it all the time, it's fine. No more warm sound, no more large power impression... just a classic sound from a classic amp. I had this amp after the V2... and I sold it without regret.

About the V4... well I'm not really sure it's a real version. The last units of the model 1 use a red circuit board like the Model 2 and 6, and not green like the previous versions. Hard to say if this is the only difference with the previous one...

That's all I know !! : )
This is really interesting! I have one M1 that is around SN 1450 and runs pretty hot - but can keep my hand on it when running. I have another that is around SN 1250 and runs much hotter and I can barely keep my hand on it. They are both running in bridged mono config. You have me wondering if the lower SN amp is actually running in bridged mono, though? I must say that the system sounds pretty stinking good though! I guess I should pop the tops on these and see if I recognize any of the internals you described.