Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on May 18, 2025, 02:46:47 pm

Title: 6BQ7a Valves
Post by: TIMBO on May 18, 2025, 02:46:47 pm
Hey guys,
A mate has about a 100 of these and had put them aside for a reason, unfortunately many years have passed and we're not sure what that was.
We were toying with Robs micro bassman and possibly using them as power valves.


Anyone see a good use for them.
Title: Re: 6BQ7a Valves
Post by: DummyLoad on May 18, 2025, 05:08:09 pm
Back in 2010 I designed an amp that made use of 6BK7, which is similar, slightly higher mu and transconductance. Both 6BQ7 and 6BK7 state design use as cascode amps for VHF. Recollection is I had good luck, amp sounded really good, but I decided not to build it and focused efforts more on conventional builds. IMO, outside of it's intended use, the 6BQ7 might be better suited for HiFi use - Similar mu to 6922/6DJ8/E88CC but with about 1/2 the transconductance.

--Pete   
Title: Re: 6BQ7a Valves
Post by: scstill on May 18, 2025, 05:11:28 pm
I built the "deluxe Micro" with the 12au7 SE in parallel plate
sounds good... https://stillampd.com/silvertone-deluxe-micro-04
Might also be an option for the 6BQ7
Title: Re: 6BQ7a Valves
Post by: TIMBO on May 19, 2025, 01:14:56 am
Thanks guys
Title: Re: 6BQ7a Valves
Post by: kagliostro on May 19, 2025, 01:35:43 am
Yes, the use in place of ecc88 seems affordable

Franco
Title: Re: 6BQ7a Valves
Post by: Merlin on May 19, 2025, 09:47:13 am
Yes, the use in place of ecc88 seems affordable
+1 Basically the same as the 6DJ8/ECC88. Popular for hi-fi
Title: Re: 6BQ7a Valves
Post by: kagliostro on May 20, 2025, 03:57:20 pm
At Diy Italia we are planning an SE with a GU-50 as power tube (with a particular circuitry, not yet established in final way)

As that tube require a strong drive we have plan to use a driver between the preamp and the power tube, this driver is an ecc88 or equivalent tube

Franco