AudiogoN Forums: Preamps w/HT BYPASS that works when preamp is OFF.

Preamps w/HT BYPASS that works when preamp is OFF.

I have spent quite a bit of time researching this issue here and on other fora. I have been looking for a thread that lists the stereo preamplifiers that have home theater (or "cinema," as some manufacturers call it) bypass that works while the preamp is turned off. I think this list would be very helpful to those who have hybrid systems, which seems to be the majority of audiophiles.

I will start the list with those that I know operate this way, either through personal use or through research on the internet. Please feel free to add to the list, but please limit your contributions to the preamps that meet the criteria above. I will break down the list into two parts: Preamps that have XLR HT bypass input and preamps that have RCA HT bypass input only. Please indicate next to the model listed whether it is tube or solid state, fully-balanced or not.

PREAMPS WITH XLR HT BYPASS INPUTS:
Cary SLP-05 (tube, fully-balanced)
Cary SLP-2002 (tube, fully-balanced)
Modwright LS 36.5 (tube, fully-balanced)

PREAMPS WITH RCA HT BYPASS INPUTS:
Supratek Chenin (tube)
Supratek Chardonnay (tube)
Rogue Perseus (tube)
Gill Audio Alana (tube) [HT Bypass available by request]
Aesthetix Janus (tube, fully balanced)
Aesthetix Calypso (tube, fully balanced)

If you know through personal experience that any of this information is incorrect, please feel free to suggest corrections.

Asindc (Threads | Answers | This Thread)

11-18-09

Responses (1-23 of 23)

Click title to read one, or click date to read all below it.

11-18-09 Cary slp98 has ht bypass when the unit is off. it must be s ... Macdadtexas

11-18-09: Asindc
Macdadtexas,

I believe it is only the F1 version of the Cary SLP-98 that has HT bypass, but I agree that it should be added to the list. ADDITION:

PREAMPS WITH RCA HT BYPASS INPUTS:
Cary SLP-98, F1 version (tube)
Asindc (Threads | Answers | This Thread)

11-18-09: Asindc
CORRECTION:

PREAMPS WITH RCA HT BYPASS INPUTS:
Modwright LS 36.5 (tube, fully-balanced)

I had previously listed this in the XLR category. Its HT bypass is single-ended only.
Asindc (Threads | Answers | This Thread)

11-18-09 What good is it unless the unit defaults to the ht bypass wh ... Kennyt

11-18-09 The dodd battery powered preamp ht bypass works when the uni ... Audiofankj

11-18-09: Asindc
Kennyt:

I know that the Carys' HT bypass works when the unit is powered off. They default to HT bypass automatically. I cannot speak for the others on this list.

The benefits of "powered off" HT bypass:

1) Saves on tube life if it is a tube pre. Not a big difference, but a difference nonetheless.

2) Saves on electricity. Same idea as #1.

3) Saves on heat. Same idea as #1 and #2.

4) Prevents possible ground loop hum from being introduced into HT system by having it interact with the preamp while it is on. I have experienced this before.

5) The security of knowing that the preamp is not processing the HT signal at all. Some might prefer that, but I do not.
Asindc (Threads | Answers | This Thread)

11-18-09: Asindc
ADDITION:

PREAMPS WITH RCA HT BYPASS INPUTS:
Dodd Battery Powered Preamp
Asindc (Threads | Answers | This Thread)

11-18-09: Asindc
Kennyt:

I will add another reason for wanting to leave the preamp off. The only reason I have a hybrid system is because I don't have the space for separate systems (I would imagine that is the primary reason why most do not). I prefer to think of them as two separate systems occupying the same room, with the only thing in common between them is the utilization of the amp(s) and speakers. In addition to the reasons stated above, I see no reason why I should have to turn on the preamp to bypass it, especially when it is not necessary.
Asindc (Threads | Answers | This Thread)

11-18-09 The tad 150 signature has rca ht bypass - work with the prea ... Bdgregory

11-18-09: Asindc
Updated list:

PREAMPS WITH XLR HT BYPASS INPUTS:
Cary SLP-05 (tube, fully-balanced)
Cary SLP-2002 (tube, fully-balanced)

PREAMPS WITH RCA HT BYPASS INPUTS:
Modwright LS 36.5 (tube, fully-balanced)
Supratek Chenin (tube)
Supratek Chardonnay (tube)
Rogue Perseus (tube)
Gill Audio Alana (tube) [HT Bypass available by request]
Aesthetix Janus (tube, fully balanced)
Aesthetix Calypso (tube, fully balanced)
Cary SLP-98, F1 version (tube)
Dodd Battery Powered Preamp
TAD 150 Signature
Asindc (Threads | Answers | This Thread)

11-19-09 The vac standard preamp le i had had ht passthrough and work ... Hevac1

11-19-09 Don't most folks keep their pre on all the time, i do. unles ... Drjoe

11-20-09 tube pre, yes. ss pre, no . Bdgregory

11-20-09: Asindc
Drjoe:

Some people turned off their equipment when not in use, so it seems pointless to have to turn the preamp on just to bypass it. I do understand why some choose to leave their preamps and amps on all the time, but I have a relatively small space that gets too hot to leave my equipment on. And as Bdgregory noted, there seems to be no benefit to leaving a SS preamp on.
Asindc (Threads | Answers | This Thread)

11-20-09 well what i wrote is exactly the opposite of what i meant. i ... Bdgregory

11-20-09: Asindc
Bdgregory,

I understand your point, though I will point out that some don't want to leave tube preamps on because of tube life issues, while others do because they stay "warmed-up" that way.
Asindc (Threads | Answers | This Thread)

11-20-09 "can't see how tube gear does it unless it is just a st ... Ait

11-20-09 Sorry guys, i was thinking ss preamp but didn't say so. i le ... Drjoe

04-25-10 Quick comment on the aesthetic calypso - i've spoken to aest ... Srosenberg

04-30-10 I'm the one (maybe even the only one) who's done the ht bypa ... Dbld

07-26-10 Lector zoe. single ended tube pre, does ht bypass when off. ... Keshiri

07-27-10 Sony ta-p9000es ss, rca (5.1 bypass!) Kr4

07-28-10 Some audio valve eclipse/eklipse's. Madfloyd